Coal gangue pile yard leachate source area identification method and system

Abstract

The application discloses a coal gangue yard leachate source area identification method and system, candidate source area units are divided by combining basic information of the coal gangue yard and dynamic response information in a plurality of historical natural rainfall events; a candidate seepage path network is established by using repeatedly occurring response transmission relations among the candidate source area units, seepage migration nodes and leachate collection nodes, and coding time conditions are determined according to actual response characteristics of different paths; coding pulse infiltration sequences with distinguishable time interval orders are generated for different preliminary source areas, and time interval orders coded in continuous nodes are recovered and node response sequence relations are checked; finally, the path network is updated by using review results of the candidate seepage paths, and the range of the preliminary source area is reversely adjusted and re-coding review is implemented, so that the leachate core source area with actual hydraulic transmission evidence is obtained, and the accuracy of leachate source area identification in a complex non-homogeneous coal gangue yard is improved.

Description

Technical Field

[0001] This invention relates to the field of pollution identification technology in mining stockpiles, and in particular to a method and system for identifying leachate source areas in coal gangue stockpiles. Background Technology

[0002] Coal gangue is a solid waste generated during coal mining, washing, and processing. Due to the large amount of coal gangue produced, some coal mines have adopted open-air centralized stockpiling for disposal during long-term production, resulting in coal gangue stockpiles that are large in area, have a long storage period, and are uneven in internal composition.

[0003] Coal gangue dumps, under long-term operation and the influence of the natural environment, typically develop complex surface and internal structures. Their surfaces may contain scour channels, settlement pits, through cracks, locations of overburden damage, vehicle-trapped areas, and localized water accumulation zones. Internally, they may contain coarse-grained water-conducting zones formed by coal gangue of varying particle sizes, fine-grained water-permeable layers, historical stratification interfaces, compaction difference interfaces, and localized cavities. These structures prevent uniform rainfall infiltration and ensure that the migration direction of infiltrated water within the dump is not necessarily perfectly aligned with the surface slope.

[0004] When rainfall enters a coal gangue pile, it may come into contact with soluble salts, sulfide oxidation products, metallic components, and residual organic matter in the coal gangue, forming leachate with specific acid-base properties, electrical conductivity, sulfate content, iron, manganese, ammonia nitrogen, or other pollutant characteristics. The leachate can migrate along coarse-grained layers, fracture zones, interlayer interfaces, and underground drainage structures towards the slope toe and low-lying areas, eventually entering drainage ditches, catch basins, or surrounding water bodies.

[0005] In the pollution control of coal gangue dumps, a key issue is the inability to accurately determine the specific spatial area of ​​the dump from which pollutants originate based solely on abnormal water quality at the end-of-pipe collection well or discharge outlet. End-of-pipe leachate typically involves the convergence of multiple source areas, mixing of different water qualities and quantities, and adsorption and precipitation of pollutants. Therefore, the absolute concentration of pollutant components can no longer directly reflect the distance to the source areas or the degree of contribution from each source.

[0006] Currently, common methods for identifying source areas mainly include on-site visual surveys, end-of-pipe water quality sampling, surface runoff analysis, geophysical exploration, borehole surveys, and chemical tracer experiments. However, these methods are insufficient to accurately identify spatial source areas that actually contribute to end-of-pipe leachate in situations where the internal structure of the coal gangue pile is heterogeneous, the seepage path is concealed, leachate from multiple source areas mixes, response time delays vary significantly due to different rainfall events, and the addition of exogenous chemical tracers is unsuitable. Summary of the Invention

[0007] In order to solve the above-mentioned technical problems, the present invention provides a method and system for identifying leachate source areas in coal gangue dumps.

[0008] The technical solution of the present invention is: a method for identifying leachate source areas in coal gangue dumps, the method comprising: Acquire basic information about coal gangue dumps and dynamic response information from multiple monitoring nodes during multiple historical natural rainfall events, and divide candidate source area units based on the basic information and the dynamic response information; Based on the response transmission relationship of the candidate source area units, preset seepage migration nodes and preset leachate collection nodes in multiple historical natural rainfall events, a candidate seepage path network is established, and the corresponding coding time conditions are determined according to the response characteristics of each candidate seepage path. Preliminary source regions are determined from the candidate source region units, and encoded pulse infiltration sequences with mutually distinguishable time intervals are generated for different preliminary source regions according to the encoding time conditions. A corresponding coded pulse infiltration sequence is applied to the preliminary source region to obtain the infiltration response of multiple nodes in each candidate seepage path. The response time interval order of each node is determined according to the infiltration response. The verification result of the candidate seepage path is determined according to the continuous transmission state of the response time interval order in the candidate seepage path and the response order of each node. The candidate seepage path network is updated based on the verification results of the candidate seepage paths, and the preliminary source area is updated and re-encoded and verified based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump.

[0009] Preferably, the step of dividing candidate source region units based on the basic information and the dynamic response information includes: Based on the topographic and water catchment information in the basic information, the surface water catchment boundary of the coal gangue dump is determined, and the surface water catchment boundary is used as the spatial division boundary. The area enclosed by the surface water catchment boundary and where the surface water flows to the same drainage facility inlet is determined as an initial spatial unit, resulting in multiple initial spatial units. The initial space unit is partitioned according to the differences in the stacked attribute information within each initial space unit to obtain multiple attribute sub-units; Based on the differences in the dynamic response information of each attribute sub-unit in multiple historical natural rainfall events, the dynamic response relationship between adjacent attribute sub-units is determined; Adjacent attribute sub-units with consistent dynamic response relationships and pointing to the same seepage migration node are merged to obtain the candidate source region unit.

[0010] Preferably, establishing a candidate seepage path network based on the response transmission relationship of the candidate source area units, preset seepage migration nodes, and preset leachate collection nodes in multiple historical natural rainfall events includes: For each historical natural rainfall event, the response start points of the near-source nodes, the seepage migration nodes, and the leachate collection nodes of the candidate source area units are determined, and the response sequence between the nodes is determined based on the response start points. By screening recurring response sequence relationships from multiple historical natural rainfall events and combining them with the spatial location relationships between corresponding nodes or the connectivity relationships of drainage facilities, candidate directed connections are established from the earlier responding node to the later responding node. According to the transmission direction of the candidate directed connection, the near-source node, at least one of the seepage migration nodes and the leachate collection node are sequentially associated to form a candidate seepage path; The candidate seepage path network is established based on the node connection relationships between each candidate seepage path.

[0011] Preferably, determining the corresponding encoding time conditions based on the response characteristics of each candidate seepage path includes: Obtain the response duration and post-rainfall recovery status of multiple nodes in each candidate seepage path during the historical natural rainfall event; Based on the response duration of each node, the first target node with the longest response duration is determined from the corresponding candidate seepage paths. Combined with the response duration of the first target node and the monitoring acquisition cycle, the distinguishable time interval between adjacent coded pulses is determined. Based on the post-rainfall recovery status of each node, the second target node with the longest recovery time to a stable state is determined from the corresponding candidate seepage paths. Based on the time required for the second target node to recover to a preset stable state, the protection time interval between the two encoding verifications is determined. The distinguishable time interval and the protection time interval are determined as the coding time conditions for the corresponding candidate seepage paths.

[0012] Preferably, the step of determining preliminary source regions from the candidate source region units and generating coded pulse infiltration sequences with mutually distinguishable time intervals for different preliminary source regions according to the coding time conditions includes: Based on the candidate seepage path network, candidate source region units that have candidate seepage paths with the leachate collection node are screened to obtain the preliminary source region; Based on the coding time conditions of the candidate seepage paths corresponding to each of the preliminary source regions, multiple time interval levels for constituting the coding are determined; Multiple candidate coding sequences are generated according to different arrangement orders of the multiple time interval levels; Candidate coding sequences with different time intervals are assigned to different initial source regions to obtain the coding pulse infiltration sequence corresponding to each initial source region.

[0013] Preferably, the step of applying a corresponding coded pulse infiltration sequence to the preliminary source region, obtaining the infiltration response of multiple nodes in each candidate seepage path, determining the response time interval order of each node based on the infiltration response, and determining the verification result of the candidate seepage path based on the continuous transmission state of the response time interval order in the candidate seepage path and the response sequence of each node, includes: Once it is confirmed that natural rainfall has stopped, multiple coded pulses are sequentially applied to the corresponding preliminary source area according to the coded pulse infiltration sequence, and the infiltration response generated by each node in the candidate infiltration path is obtained; Extract the response start point corresponding to each coded pulse from the infiltration response of each node, and determine the order of the response time intervals corresponding to each node based on the time interval between adjacent response start points of each coded pulse. According to the transmission direction of the initial source area, the seepage migration node and the leachate collection node, compare the response time interval order and response sequence of each node; When the same response time intervals occur consecutively along the candidate seepage path, and the response of the subsequent node is not earlier than that of the preceding node, a path confirmation result is generated. When the response time interval order does not occur consecutively along the candidate seepage path, and / or the response of the subsequent node is earlier than that of the preceding node, a path rejection result is generated; The path confirmation result or the path rejection result is determined as the verification result of the candidate seepage path.

[0014] Preferably, the step of updating the candidate seepage path network based on the verification results of the candidate seepage paths, and updating and re-encoding the preliminary source area based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump includes: Based on the verification results of each candidate seepage path, the connection status of adjacent nodes in the candidate seepage path network is adjusted. Specifically, the connection status of adjacent nodes that generate path confirmation results is set to confirmed connection, and the connection status of adjacent nodes that generate path rejection results is set to rejection connection, thus obtaining an updated candidate seepage path network. The initial source region is updated using the updated candidate seepage path network, and the adjusted source region is re-encoded and verified. Based on the results of the re-encoding verification, the candidate seepage path network is updated, and the process is then moved to updating the preliminary source region using the updated candidate seepage path network. The adjusted source region is then re-encoded and verified until the preset iteration stop condition is met, and the final source region is output as the leachate core source region.

[0015] Secondly, the present invention also provides a leachate source area identification system for coal gangue stockpiles, the system comprising: The source area division module is used to obtain basic information about coal gangue dumps and dynamic response information of multiple monitoring nodes in multiple historical natural rainfall events, and to divide candidate source area units according to the basic information and the dynamic response information. The time-condition coding module is used to establish a candidate seepage path network based on the response transmission relationship of the candidate source area units, preset seepage migration nodes and preset leachate collection nodes in multiple historical natural rainfall events, and to determine the corresponding coding time conditions based on the response characteristics of each candidate seepage path. The infiltration sequence determination module is used to determine preliminary source regions from the candidate source region units and generate coded pulse infiltration sequences with mutually distinguishable time intervals for different preliminary source regions according to the coding time conditions. The response verification module is used to apply a corresponding coded pulse infiltration sequence to the preliminary source region, obtain the infiltration response of multiple nodes in each candidate seepage path, determine the response time interval order of each node according to the infiltration response, and determine the verification result of the candidate seepage path according to the continuous transmission state of the response time interval order in the candidate seepage path and the response order of each node. The source area determination module is used to update the candidate seepage path network based on the verification results of the candidate seepage paths, and update and re-encode the preliminary source area based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump.

[0016] Thirdly, this application provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method provided in the first aspect of this application.

[0017] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method provided in the first aspect of this application.

[0018] The beneficial effects of this invention are: This invention first divides candidate source area units by combining basic information of coal gangue dumps with dynamic response information from multiple historical natural rainfall events. This ensures that the source area division simultaneously reflects surface water catchment conditions, differences in dumping structures, and actual infiltration response characteristics, reducing source area boundary distortion caused by dividing solely based on fixed grids or surface slope aspects. Then, it establishes a candidate seepage path network using recurring response transmission relationships among candidate source area units, seepage migration nodes, and leachate collection nodes. Furthermore, it determines encoding time conditions based on the actual response characteristics of different paths, enabling subsequent active infiltration processes to adapt to the transmission speed, response broadening, and recovery state of different paths. This avoids overlapping of adjacent responses due to using a uniform time interval. The experimental time was ineffectively extended; furthermore, coded pulse infiltration sequences with distinguishable time intervals were generated for different preliminary source areas. By restoring the time interval order of the codes in continuous nodes and verifying the response sequence of nodes, the downstream response was correlated with specific preliminary source areas and candidate seepage paths, thereby reducing the impact of multi-source leachate mixing, pollutant concentration decay, and inconsistent response amplitudes of different monitoring indicators on source area judgment. Finally, the path network was updated using the verification results of candidate seepage paths, and the scope of the preliminary source areas was adjusted in reverse and re-coded for verification, so that the source area identification results could gradually converge from a large range of suspected areas to leachate core source areas with actual hydraulic transfer evidence. Therefore, this scheme, without relying on absolute pollutant concentrations or exogenous chemical tracers, achieved a continuous closed loop between natural rainfall response analysis, candidate path establishment, active coding verification, and source area spatial refinement, improving the accuracy, verifiability, and targeted determination of subsequent treatment scope in complex heterogeneous coal gangue dumps. Attached Figure Description

[0019] Figure 1 A flowchart illustrating a method for identifying leachate source areas in a coal gangue dump; Figure 2 This is a schematic diagram of a leachate source identification system for coal gangue dumps. Detailed Implementation

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is transmission of electrical signals or data between the connected objects.

[0024] like Figure 1 As shown, this invention provides a method for identifying leachate source areas in coal gangue dumps. The method includes steps 101 to 105, wherein: 101. Obtain basic information about coal gangue dumps and dynamic response information from multiple monitoring nodes during several historical natural rainfall events, and divide candidate source area units based on the basic information and dynamic response information.

[0025] In this embodiment, the coal gangue stockpile can be a long-established historical coal gangue stockpile, a newly built or temporarily used coal gangue stockpile, a coal gangue stockpile that has undergone partial coverage remediation, or a composite stockpile formed by different storage periods, different coal gangue sources, or different processing batches. The identified leachate source area refers to the spatial area that actually receives rainfall infiltration, generates or releases pollutants, and can be transferred through the internal seepage channels of the stockpile or artificial drainage facilities to the seepage point at the toe of the slope, drainage ditch, collection well, regulating pond inlet, or external discharge outlet.

[0026] Basic information refers to information reflecting the spatial structure, infiltration conditions, and drainage relationships of coal gangue stockpiles. It can include at least topographical water catchment information, stockpile attribute information, surface infiltration conditions, internal water content, and drainage facility connectivity information. Basic information does not necessarily need to be obtained entirely through a single method; it can be obtained by combining on-site measurements, UAV mapping, historical imagery, stockpile operation records, as-built documentation, shallow sampling, existing survey data, and on-site observations.

[0027] Dynamic response information refers to the continuous changes in each monitoring node relative to its pre-rainfall stable state during historical natural rainfall events. Dynamic response information can include changes in water content, water volume, water level, temperature, and water quality indicators. Water quality indicators can include pH, conductivity, sulfate, iron, manganese, ammonia nitrogen, chemical oxygen demand, dissolved organic matter, or other indicators selected based on the composition of coal gangue. This embodiment does not require high-frequency online monitoring of all water quality indicators; as long as the order and duration of the corresponding indicators entering abnormal states can be determined, it can serve as a basis for path identification.

[0028] Candidate source region units are spatial regions formed by further dividing or merging them based on the differences in dynamic responses from multiple historical natural rainfall events. Candidate source region units should have relatively consistent infiltration initiation conditions, pollutant release conditions, and downstream response orientations.

[0029] In step 101, the topographic and water catchment information of the coal gangue stockpile is first obtained. This information may include the stockpile boundary, surface elevation, slope aspect, slope gradient, watershed ridges, scour ditches, local depressions, water accumulation locations, slope toe locations, drainage ditch orientation, and the location of water collection facilities. For stockpiles that have been stored for a long time and whose surface topography has changed significantly, the current measurement results should be used first to determine the actual topography. Historical drawings or as-built data are mainly used to determine the evolution of the stockpile and to identify drainage ditches, conduits, or existing trenches that may be covered by coal gangue.

[0030] Further information on the stockpiling attributes of coal gangue dumps should be obtained. This information can include the source of the coal gangue, the year of stockpiling, the dumping batch, particle size distribution, differences in coal content, compaction state, weathering state, type of surface overburden, differences in overburden thickness, historical excavation locations, historical fire areas, and historical remediation areas. For areas where the stockpiling year cannot be accurately determined, relative classification can be performed based on the degree of surface weathering, vegetation growth status, particle fragmentation, and spatial relationship with known stockpiling areas.

[0031] Further information on surface infiltration conditions is needed. These conditions may include fissure density, fissure connectivity, settlement pits, locations of overburden damage, locally exposed areas, compacted zones formed by vehicle traffic, scour ditches, waterlogged areas, and areas disturbed by vegetation roots. This information is used to determine whether different rainfall infiltration initiation mechanisms exist within the same catchment area.

[0032] Further obtain information on the internal water content. This information can be obtained using water content sensors at different depths, dielectric state sensors, temperature sensors, or other monitoring devices capable of reflecting changes in moisture. Monitoring nodes are not required to be evenly distributed within the stockpile, but should be preferentially located below suspected infiltration sites, at locations of changes in stockpile properties, upstream of the slope toe, near suspected coarse-grained drainage zones, and near historical drainage structures.

[0033] Further information on drainage facility connectivity should be obtained. This information may include the flow direction between surface drainage ditches, the connection between drainage ditches and sump pits, the location of underground drainage pipes, historically abandoned drainage pipes, and existing trenches that may be covered by landfill. For drainage facilities that exist in the drawings but are damaged, blocked, or buried on site, they should be handled according to their current actual connectivity status, and their continued drainage function should not be determined solely based on the drawings.

[0034] Further, dynamic information on water quantity and quality from multiple monitoring nodes will be obtained. Water quantity dynamic information may include slope toe seepage flow, drainage ditch flow, inflow status of collection wells, and water level changes. Water quality dynamic information may include pH, conductivity, sulfate, iron, manganese, ammonia nitrogen, and other indicators that reflect the state of coal gangue leachate. When the existing leachate concentration is high, infiltration of clean water or rainfall may manifest as a short-term decrease in conductivity or pollutant concentration; therefore, the dynamic response can be either an increase or a decrease in value.

[0035] By combining the above basic information and dynamic response information, we can simultaneously describe the surface water catchment, internal structural differences, infiltration initiation conditions, and downstream transmission relationships of the storage yard, avoiding the need to classify source areas solely based on end-of-pipe pollutant concentrations or surface slope aspect.

[0036] 102. Based on the response transmission relationship of candidate source area units, preset seepage migration nodes and preset leachate collection nodes in multiple historical natural rainfall events, establish a candidate seepage path network, and determine the corresponding coding time conditions based on the response characteristics of each candidate seepage path.

[0037] Among them, seepage migration nodes refer to the locations set between candidate source area units and leachate collection nodes to characterize the transfer state of moisture or leachate. Seepage migration nodes can be locations for monitoring the water content within the pile body, seepage points at the toe of slopes, abnormally moist zones, drainage ditch sections, inlets of drainage pipes, or upstream locations of collection wells.

[0038] A leachate collection node refers to a location that receives leachate generated by one or more candidate source units. It may include a sump at the toe of a slope, the confluence of drainage ditches, a collection well, the inlet of a regulating pond, or an outlet outside the storage yard.

[0039] A candidate seepage path is a candidate seepage path in a candidate seepage path network. It refers to a directed node sequence formed based on repeated response relationships in multiple historical natural rainfall events, which leads from a candidate source area unit to a leachate collection node via at least one seepage migration node. Before being encoded and verified, a candidate seepage path only indicates the possible existence of hydraulic transfer relationships and is not directly used as the final confirmed path.

[0040] The coding timing conditions include the distinguishable time interval between adjacent coding pulses and the protection time interval between two consecutive coding verifications. The distinguishable time interval is used to ensure that two adjacent pulses can still be identified as two independent responses after path propagation and response broadening; the protection time interval is used to ensure that the previous infiltration response has entered a stable state and no longer interferes with the next coding identification.

[0041] Step 102 is used to convert the spatial candidate source region formed in step 101 into a candidate seepage path with a transmission direction, and to pass the actual response persistence and recovery state in historical natural rainfall to the subsequent coding parameter design.

[0042] Monitoring nodes may include near-source nodes located within or near candidate source units (selected as locations closest to the boundary of the source unit and only affected by infiltration from that source unit), seepage migration nodes located inside the pile body or at the toe of the slope, and collection nodes for receiving leachate. Near-source nodes are used to determine whether the candidate source area receives infiltration from the current rainfall, intermediate seepage migration nodes are used to determine whether water or leachate is transferred in the expected direction, and collection nodes are used to determine whether the corresponding source area makes an actual contribution to the terminal leachate.

[0043] 103. Determine the preliminary source region from the candidate source region units, and generate a coding pulse infiltration sequence with mutually distinguishable time interval order for different preliminary source regions according to the coding time conditions.

[0044] This process involves selecting preliminary source regions from candidate source region units that require priority active verification, and generating mutually distinguishable coded sequences for different preliminary source regions that may experience response confusion at the same collection node or shared path. The coded pulse infiltration sequence refers to the infiltration process formed by multiple clear water infiltration pulses arranged at different time intervals. The coded information is primarily carried by the order of the time intervals between adjacent pulses, rather than by the infiltration volume or downstream response amplitude. Even if pulse attenuation or broadening occurs during propagation, as long as the relative order of the time intervals between adjacent responses can be recovered, the corresponding preliminary source region can be identified.

[0045] 104. Apply the corresponding coded pulse infiltration sequence to the initial source area, obtain the infiltration response of multiple nodes in each candidate seepage path, determine the response time interval order of each node according to the infiltration response, and determine the verification result of the candidate seepage path according to the continuous transmission state of the response time interval order in the candidate seepage path and the response order of each node.

[0046] This process involves active verification based on historical natural rainfall calibration. It is not a typical water injection test, but rather the application of the coding time conditions obtained in step 102 and the differentiated coding sequence generated in step 103 to the corresponding preliminary source region, and the determination of whether a candidate path is valid based on the transmission status of the coding in consecutive nodes.

[0047] 105. Update the candidate seepage path network based on the verification results of the candidate seepage paths, and update and re-encode the preliminary source area based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump.

[0048] This step involves feeding back the path verification results from step 104 to the candidate seepage path network and using the updated path structure to adjust the initial source region's extent. Therefore, the coding verification not only determines whether a path is connected but also directly influences the next round of source region delineation and coding allocation.

[0049] Using the aforementioned technical solution, candidate source area units are first delineated by combining basic information of the coal gangue stockpile with dynamic response information from multiple historical natural rainfall events. This ensures that the source area delineation simultaneously reflects surface water catchment conditions, differences in stockpile structure, and actual infiltration response characteristics, reducing source area boundary distortion caused by relying solely on fixed grids or surface slope aspect. Then, a candidate seepage path network is established using the recurring response transmission relationships between candidate source area units, seepage migration nodes, and leachate collection nodes. Furthermore, encoding time conditions are determined based on the actual response characteristics of different paths, enabling subsequent active infiltration processes to adapt to the transmission speed, response broadening, and recovery state of different paths, avoiding the negative impact of using a uniform time interval on adjacent responses. The experiment should not overlap or extend the test time ineffectively; further, it should generate coded pulse infiltration sequences with distinguishable time intervals for different preliminary source areas, and by restoring the time interval order of the codes in continuous nodes and verifying the response sequence of nodes, it should correspond the downstream response with specific preliminary source areas and candidate seepage paths, thereby reducing the impact of multi-source leachate mixing, pollutant concentration decay, and inconsistent response amplitudes of different monitoring indicators on source area judgment; finally, it should update the path network using the verification results of candidate seepage paths, and reversely adjust the scope of the preliminary source areas and implement re-coding verification, so that the source area identification results can gradually converge from a large range of suspected areas to leachate core source areas with actual hydraulic transfer evidence. Therefore, this scheme achieves a continuous closed loop between natural rainfall response analysis, candidate path establishment, active coding verification, and source area spatial refinement without relying on absolute pollutant concentrations and exogenous chemical tracers, improving the accuracy, verifiability, and targeted determination of subsequent treatment scope in complex heterogeneous coal gangue dumps.

[0050] In an exemplary embodiment, dividing candidate source area units based on basic information and dynamic response information includes: determining the surface water catchment boundary of the coal gangue dump based on the topographic water catchment information in the basic information, and using the surface water catchment boundary as the spatial division boundary, defining the area enclosed by the surface water catchment boundary and where the surface water flows to the same drainage facility inlet as an initial spatial unit, thus obtaining multiple initial spatial units; partitioning the initial spatial units according to the differences in the storage attribute information within each initial spatial unit, thus obtaining multiple attribute sub-units; determining the dynamic response relationship between adjacent attribute sub-units based on the differences in the dynamic response information of each attribute sub-unit in multiple historical natural rainfall events; and merging adjacent attribute sub-units with consistent dynamic response relationships and pointing to the same seepage migration node to obtain candidate source area units.

[0051] Among them, topographic water catchment information is used to reflect the direction of surface flow, collection location and entry into drainage facilities that may be formed after rainfall falls on the surface of the coal gangue dump. It can include the boundary of the coal gangue dump, surface elevation, slope aspect, slope, watershed ridge, scour ditch, local depression, water accumulation location, slope toe location, drainage ditch direction and water collection facility location.

[0052] Topographical water catchment information can be obtained through on-site topographic surveys, UAV mapping, existing topographic maps, as-built data, historical images, or a combination of the above methods. For coal gangue stockpiles that have been stored for a long time, have experienced significant surface erosion, or have undergone substantial settlement, the topographical conditions obtained from the current measurements should be prioritized. Historical data can be used to identify drainage ditches, underground drainage facilities, or existing trenches that have been covered by coal gangue, but it cannot directly replace the actual water catchment relationships at the current site.

[0053] After obtaining topographical water catchment information, the direction of surface water flow at each surface location is determined based on the decreasing direction of surface elevation and slope aspect, and the corresponding catchment outlet is traced along the surface water flow direction. The catchment outlet can be the inlet of a drainage ditch, the inlet of a sump, the toe of a slope, or other drainage facility inlets capable of receiving surface runoff.

[0054] Further, the surface catchment boundary is determined based on the location of watershed ridges, slope aspect changes, and drainage facilities that provide actual separation. The surface catchment boundary refers to the spatial boundary that separates surface areas flowing towards the inlets of different drainage facilities. For example, when surface water on both sides of a watershed ridge flows towards the east and west drainage ditches respectively, the watershed ridge can be used as the boundary between the two surface catchment areas.

[0055] After determining the surface catchment boundaries, the area enclosed by adjacent surface catchment boundaries is used as the area to be divided, and it is determined whether the surface water in this area flows to the same drainage facility inlet. When all surface locations within an enclosed area flow along the corresponding slope direction to the same drainage ditch inlet, sump inlet, or slope toe drainage location, the enclosed area is defined as an initial spatial unit.

[0056] In other words, an initial spatial unit should simultaneously meet two conditions: first, the area has a relatively complete boundary formed by a watershed ridge or a change in the direction of surface water flow; second, the surface runoff generated within the area ultimately enters the same drainage facility inlet.

[0057] After obtaining multiple initial spatial units, the stacking attribute information within each initial spatial unit is acquired. The stacking attribute information reflects the formation time, composition, stacking structure, and surface protection status of coal gangue, and may include the source of coal gangue, the year of stacking, the dumping batch, particle size composition, coal content differences, compaction status, weathering status, surface cover type, cover integrity status, historical excavation location, historical fire area, and historical remediation area.

[0058] Information on stockpiled properties can be obtained through coal gangue yard operation records, dumping records, historical images, on-site observations, shallow sampling, existing exploration data, or a combination of the above methods. For areas where the stockpiling year or dumping batch cannot be accurately determined, relative classification can be performed based on surface weathering degree, vegetation growth status, particle fragmentation degree, and spatial relationship with known stockpiling areas.

[0059] For each initial spatial unit, identify the locations where the internal stacking attributes change significantly, and use these locations as candidate boundaries for attribute partitioning.

[0060] When regions from different storage periods exist within the same initial spatial unit, they can be partitioned according to the location of changes in storage period. Earlier storage areas have typically undergone longer periods of weathering and rainfall, and their fracture development, soluble component release, and surface infiltration capacity may differ from those of more recently stored areas.

[0061] When both coarse-particle concentrated areas and fine-particle concentrated areas exist within the same initial spatial unit, the area can be partitioned based on the location of changes in particle size distribution. Coarse-particle areas have larger pores and may form faster vertical infiltration or dominant seepage channels; fine-particle areas may form low-permeability layers, perched layers, or slow-release zones.

[0062] When compacted and loose zones coexist within the same initial spatial unit, the area can be divided according to the location of changes in compaction status. Vertical infiltration in compacted zones is usually limited, but moisture may migrate laterally along the surface of the compacted layer; loose zones, on the other hand, may receive rainfall more quickly and propagate to deeper layers.

[0063] When the cover layer remains intact in some areas while being damaged, cracked, or subsided in others, it can be divided into zones based on its integrity. Intact cover areas typically impede rainwater infiltration, while damaged cover areas may become concentrated rainwater infiltration sites.

[0064] For example, if an initial spatial unit is located at the same drainage ditch inlet, but its upper part is an old, weathered storage area, its lower part is a loose area of ​​coarse particles formed by recent dumping, and its middle part is a compacted zone formed by long-term vehicle rolling, then the initial spatial unit can be divided into multiple attribute sub-units according to the storage period, particle size composition, and compaction state.

[0065] The attribute sub-unit is a spatial partition formed based on relatively stable differences in storage attributes. The storage period, particle composition, compaction state, or cover state within it are relatively consistent. The attribute sub-unit only indicates that different areas may have different infiltration and pollutant release mechanisms, and still needs to be verified and corrected through actual dynamic responses in multiple historical natural rainfall events.

[0066] Historical natural precipitation events refer to precipitation events with a relatively complete process of precipitation input, infiltration initiation, node transmission, terminal response, and post-precipitation recovery. To avoid mutual interference between adjacent precipitation events, continuous monitoring data can be divided into multiple independent natural precipitation events or composite natural precipitation events based on precipitation intervals and the recovery status of monitoring nodes.

[0067] When rainfall transitions from a state of no rainfall to a state of continuous rainfall, and at least one surface or shallow water content monitoring node shows continuous change, a natural rainfall event can be identified as having begun. When rainfall stops, and no further rainfall capable of causing continuous infiltration occurs during subsequent observation periods, the rainfall input can be identified as having ended.

[0068] If the time interval between two rainfall events is short, and the water content, water quantity, or water quality response caused by the first rainfall event has not yet entered the recovery phase, the two rainfall events can be treated as the same composite rainfall event; if the main monitoring nodes between the two rainfall events have recovered to a stable state, the two rainfall events can be treated as independent events.

[0069] For each natural rainfall event, it can be divided into the pre-rainfall stabilization stage, infiltration initiation stage, path propagation stage, terminal response stage, and post-rainfall recovery stage based on the rainfall process and node response process.

[0070] Dynamic response information can include the response start point, response duration, response change direction, order of appearance of pollutants, and recovery status after rainfall for each attribute sub-unit at the corresponding monitoring location.

[0071] The response start point refers to the initial position where monitoring data transitions from a stable state to a state of continuous change. For example, if the water content deviates from the pre-rainfall stable state in the same direction at multiple consecutive sampling times, the moment of the first sustained deviation can be used as the response start point. Abrupt changes occurring at a single sampling time and then immediately recovering are not considered valid response start points.

[0072] The response duration status reflects the duration and trend of changes in water content, water quantity, or water quality after rainfall infiltration into an attribute sub-unit. Areas with shorter response durations may correspond to rapid water conduction and discharge processes, while areas with longer response durations may correspond to slower infiltration, local retention, or slow release processes.

[0073] Post-rainfall recovery status reflects the speed at which monitoring data recovers to a relatively stable state after rainfall stops. If a certain area recovers quickly after rainfall, it indicates that its water storage capacity is relatively weak or its drainage rate is fast; if another adjacent area maintains a high water content for a long time, it may have a fine-particle perched layer, a compacted layer, or a locally enclosed water storage space.

[0074] In multiple historical natural rainfall events, the response start point, response duration, and post-rainfall recovery state of adjacent attribute sub-units are compared, and it is determined whether the response differences of adjacent attribute sub-units are repeated.

[0075] When two adjacent attribute sub-units consistently exhibit different dynamic response relationships in multiple natural rainfall events, such that one starts earlier and the other starts later, or one recovers quickly and the other recovers slowly, it can be determined that the two have different dynamic response relationships.

[0076] When two adjacent attribute sub-units start up almost simultaneously under different rainfall intensities and durations, have similar response durations, enter abnormal states in the same order, recover from rainfall in similar states, and their downstream responses both point to the same seepage migration node, it can be determined that the two have a consistent dynamic response relationship.

[0077] Dynamic response relationships should be determined primarily based on repeated results from multiple natural rainfall events, avoiding the use of single sensor anomalies, localized artificial drainage, or accidental surface runoff as the basis for adjusting source area boundaries. When the number of available historical rainfall events is limited, finer attribute sub-unit divisions can be temporarily retained, with the decision to maintain the original state or merge them made during subsequent coding review.

[0078] It should be noted that after adjacent attribute sub-units are partitioned according to their storage attributes, they already have preliminary spatial boundaries. When adjacent attribute sub-units have different dynamic response relationships, they should be retained separately to avoid classifying them as the same source region simply because they are spatially adjacent or converge towards the same surface drainage facility. For example, although adjacent coarse-grained zones and compacted zones are both located within the same initial spatial unit, the coarse-grained zone activates rapidly under light rain conditions, while the compacted zone only activates in the later stages of continuous rainfall; therefore, they should be designated as separate candidate source region units.

[0079] For adjacent attribute sub-units with consistent dynamic response relationships, their downstream orientation relationship is further determined. Orientation to the same seepage migration node means that the responses of two adjacent attribute sub-units formed in multiple historical natural rainfall events are preferentially transmitted to the same slope toe infiltration point, the same abnormally humid zone, the same drainage ditch section, the same inlet of the drainage pipe, or other identical seepage migration nodes.

[0080] When two adjacent attribute sub-units are activated essentially synchronously in multiple natural rainfall events, with consistent response duration and recovery states, and both pointing to the same seepage migration node, they can be merged into the same candidate source region unit. This merging is not based solely on spatial adjacency, but rather on their consistent infiltration initiation, pollution release, and downstream transmission behaviors, indicating that they can be treated as the same hydraulic response unit under current monitoring and resolution capabilities.

[0081] For example, if adjacent old and new storage areas, although stored for different periods, undergo changes in water content during multiple rainfalls, exhibit the same order of electrical conductivity and sulfate changes, recover at similar rates after rainfall, and both point to the same infiltration point at the toe of the slope, then they can be merged into the same candidate source area unit.

[0082] Conversely, if two adjacent attribute sub-units have similar response starting points, but one mainly points to the seepage point at the eastern slope toe and the other mainly points to the western drainage ditch, they should not be merged because they have different downstream migration directions.

[0083] The final candidate source region units are no longer determined solely by surface catchment boundaries or storage properties, but are simultaneously constrained by surface catchment relationships, differences in storage structures, actual rainfall infiltration response, and downstream seepage direction relationships. This provides source-end nodes with relatively consistent infiltration initiation conditions and downstream direction relationships for the subsequent establishment of candidate seepage path networks, thereby avoiding the simultaneous inclusion of fast infiltration areas, slow retention areas, or areas pointing to different downstream paths within a single candidate source region unit, and improving the accuracy of subsequent path establishment and coding verification.

[0084] In an exemplary embodiment, a candidate seepage path network is established based on the response transmission relationship of candidate source area units, preset seepage migration nodes, and preset leachate collection nodes in multiple historical natural rainfall events. This includes: for each historical natural rainfall event, determining the response starting points of the near-source nodes, seepage migration nodes, and leachate collection nodes of the candidate source area units, and determining the response sequence relationship between each node based on the response starting points; filtering recurring response sequence relationships from multiple historical natural rainfall events, and establishing candidate directed connections from earlier responding nodes to later responding nodes based on the spatial location relationship between corresponding nodes or the connectivity relationship of drainage facilities; sequentially associating near-source nodes, at least one seepage migration node, and leachate collection node according to the transmission direction of the candidate directed connections to form candidate seepage paths; and establishing a candidate seepage path network based on the node connection relationship between each candidate seepage path.

[0085] The response start point refers to the starting position at which a monitoring node transitions from a stable state to a continuously changing state.

[0086] For nodes in the water-bearing state, when the monitoring data deviates from the stable baseline in the same direction for multiple consecutive collection times, and this deviation persists, the moment when the continuous deviation state is first entered is determined as the response starting point.

[0087] For a flow node, when the flow changes from a stable base flow to a continuously rising state, or when a new stable outflow appears at a location that previously had no outflow, the starting position of the change is determined as the response starting point.

[0088] For water quality nodes, when the conductivity, pH, or target pollutant component continuously deviates from the pre-rainfall state, and adjacent sampling results support the same direction of change, the location of the first continuous deviation is determined as the response starting point.

[0089] A sudden change at a single acquisition moment is not directly used as the response starting point. If the change is immediately resolved and no corresponding change is observed in adjacent nodes, it is excluded as an isolated anomaly. When the acquisition cycles of different monitoring devices vary significantly, the response starting point can be standardized to event stages such as early start, mid-term start, and late start, without forcing comparisons of precise times beyond the acquisition capability.

[0090] Based on the response starting point of each node, the response sequence among candidate source units, seepage migration nodes, and leachate collection nodes can be established. For example, if candidate source unit A first experiences a change in water content, then slope toe node B subsequently experiences outflow, drainage ditch node C further experiences an increase in flow, and collection well D finally experiences a change in conductivity, then the response sequence is A, B, C, D.

[0091] In addition to the response initiation point, the order of appearance of pollutants can also be recorded. The order of appearance of pollutants refers to the relative sequence in which different water quality indicators enter an abnormal state. For example, conductivity and sulfate change first, followed by iron and manganese. If this order appears consecutively near the candidate source region, intermediate nodes, and sink nodes, it can serve as supplementary supporting evidence of response transmission relationships, without requiring the absolute pollutant concentrations at different nodes to be the same.

[0092] For multiple historical natural rainfall events with different rainfall intensities, durations, or pre-rainwater conditions, the repetition of response sequences among nodes is statistically analyzed. Only response sequences that occur repeatedly across multiple events are considered repeated responses. For example, if at least two events out of at least three valid historical natural rainfall events maintain the same response order, or if the proportion of identical response sequences exceeds 60%, these are prioritized for establishing candidate directed connections to reduce misjudgments caused by single, random fluctuations.

[0093] When establishing candidate directed connections, the spatial relationships between nodes or the connectivity of drainage facilities should also be considered. Spatial relationships can include topographical descent, upstream and downstream adjacency, slope toe correspondence, and the direction of suspected internal water guides; drainage facility connectivity can include upstream and downstream relationships of drainage ditches, connections between drainage ditches and sump pits, underground drainage pipes, and relationships between historical ditches.

[0094] For example, if candidate source region A responds multiple times earlier than slope toe node B, and although there is no direct surface runoff relationship between A and B, there is a coarse-grained layer or historical stratification interface between them, then A to B can be set as a suspected internal seepage connection. Conversely, if a node frequently responds independently when none of its upstream nodes respond, then that node may be receiving other unidentified sources and should not be directly incorporated into the existing candidate path.

[0095] The established candidate directed connections only represent possible hydraulic transmission relationships, and further verification is still required through encoded pulse infiltration.

[0096] Following the direction from the first responding node to the next responding node, the near-source node is associated with the leachate collection node through one or more seepage migration nodes, or the near-source node is directly associated with the leachate collection node, forming a candidate seepage path.

[0097] For example, if candidate source unit A is activated first, then outflow occurs at slope toe infiltration point B, the flow rate increases after drainage ditch section C, and the water quality changes last at collection well D, then candidate directed connections from A to B, B to C, and C to D can be formed, thus forming candidate seepage paths from A to B to C to D.

[0098] When different candidate seepage paths share some nodes or have some node connections, all paths are organized into a candidate seepage path network. Nodes in the candidate seepage path network can have multiple upstream connections or multiple downstream connections to represent situations such as the convergence of different source regions, the diversion of the same source region, and path bifurcation.

[0099] Each node connection can have its path status set. Connections that have not been coded and verified but are supported by multiple historical natural rainfall events are candidate connections; connections with subsequent continuous coding can be updated to confirmed connections; connections with inconsistent coding order can be updated to negative connections; when there is local stagnation or bypass evidence, they can also be set as stagnant connections or connections to be verified.

[0100] By using a candidate seepage path network, scattered monitoring data can be organized into a path structure with spatial orientation and node connection relationships, providing a foundation for subsequent reverse screening of preliminary source areas and coding verification. In an exemplary embodiment, determining the corresponding coding time conditions based on the response characteristics of each candidate seepage path includes: acquiring the response duration and post-rainfall recovery status of multiple nodes in each candidate seepage path during historical natural rainfall events; determining the first target node with the longest response duration from the corresponding candidate seepage path based on the response duration of each node, and determining the distinguishable time interval between adjacent coding pulses by combining the response duration of the first target node with the monitoring acquisition cycle; determining the second target node with the longest recovery time to a stable state from the corresponding candidate seepage path based on the post-rainfall recovery status of each node, and determining the protection time interval between two consecutive coding verifications based on the time required for the second target node to recover to a preset stable state; and determining the distinguishable time interval and the protection time interval as the coding time conditions for the corresponding candidate seepage path.

[0101] The response duration state characterizes the process by which a node transitions from the response initiation point to a peak state, a stable change state, or a slow recovery state. When concentrated rainfall input propagates within the stack, due to porosity differences, path diversion, local water storage, and re-release, the originally concentrated input process may transform into a longer-lasting downstream response; this phenomenon is called response broadening.

[0102] The response of a fast water-conducting path usually has a clear start and end point and a small response broadening; paths with more fine particles, more branching paths, or obvious local water storage usually have a longer response duration, and adjacent infiltration events are likely to overlap downstream.

[0103] Post-rainfall recovery refers to the process by which nodes gradually transition from a responsive state to a stable state after rainfall ceases. Fast paths typically stop outflow or recover to their baseline moisture content relatively quickly, while stagnant areas may continue to flow slowly or maintain a higher moisture content after rainfall stops.

[0104] This embodiment considers the stage where the previous rainfall or infiltration event still shows significant and continuous changes in the monitoring data as the path memory stage. Only when the data at major nodes has entered a stable state and no longer continuously forms response starting points related to the previous event is the path memory considered to have largely faded. The response inflection point refers to the position where the monitoring data changes from one stable trend to another. For example, a change in monitoring values ​​from a continuous decline to a renewed rise, or from a slow rise to a rapid rise, can both constitute a response inflection point. First, determine the basic resolvable time based on the acquisition cycle of the monitoring equipment. The time interval between two adjacent responses should be sufficient for the monitoring equipment to record two different changes, avoiding the situation where two pulses fall into the same acquisition interval and cannot be distinguished.

[0105] Secondly, by comparing the response duration of each node in the same candidate seepage path, the node with the longest response duration or the most significant response broadening among multiple historical natural rainfall events is identified as the first target node. The first target node represents the node in the candidate path that is least conducive to distinguishing adjacent pulses.

[0106] The distinguishable time interval refers to the minimum time interval required for two adjacent coded pulses to be identified as two independent responses after they have propagated to the node with the longest response duration in the candidate percolation path.

[0107] When determining the resolvable time interval, the response duration of the first target node is used as the primary basis, and the time interval is determined in conjunction with the acquisition cycle of the monitoring equipment. The set time interval should allow the response of the previous pulse to enter a stable or significantly slowed-down phase before the response of the next pulse begins to appear. At the same time, it should be able to cover at least the multiple acquisition cycles required for the monitoring equipment to independently record two response change processes. For example, the larger of the response duration of the first target node and at least two monitoring acquisition cycles is determined as the resolvable time interval. Subsequently, the resolvable time interval is rounded up according to the monitoring acquisition cycle to obtain the basic time interval.

[0108] Furthermore, by comparing the recovery processes of each node in the same candidate seepage path after rainfall ceases, the node requiring the longest time to recover to a steady state is determined as the second target node. The first and second target nodes can be the same node or different nodes.

[0109] The preset stable state does not require the second target node to fully recover to a fixed value before the rainfall, but rather requires that its trend of change has stabilized and no longer continuously form a clear response start point, response inflection point, or continuous outflow process related to the previous rainfall or the previous coded pulse.

[0110] The protection time interval between the two encoding reviews is determined based on the time required for the second target node to reach a preset stable state. If the encoding response of the previous preliminary source region has not yet faded, it is not advisable to immediately perform encoding review on another preliminary source region pointing to the same aggregation node or sharing a part of the path, so as to avoid overlap of different codes downstream.

[0111] The protection time interval refers to the shortest waiting time required from the completion of the previous coding verification to the commencement of the next coding verification. It is used to prevent the previous infiltration response from interfering with the next coding identification. The protection time interval primarily constrains the waiting time between different coding trials, while the distinguishable time interval primarily constrains the interval between adjacent pulses within the same coding sequence. These two mechanisms respectively address the issues of intra-sequence distinguishability and inter-sequence interference. Specifically, the protection time interval is equal to the rounded-up value of the time required for the second target node to recover to a preset stable state.

[0112] The coding time conditions for candidate seepage paths include distinguishable time intervals and protection time intervals. When generating subsequent coding sequences, each time interval level must not be lower than the distinguishable time interval required for the corresponding path; when conducting coding verification sequentially between different preliminary source areas, at least a protection time interval appropriate to the relevant path should be waited for.

[0113] By determining the coding time conditions based on historical natural rainfall responses, subsequent active infiltration parameters are derived from the actual infiltration velocity, response broadening, and recovery rate of the stockpile, rather than from fixed time intervals uniform across the entire site used by operators.

[0114] In an exemplary embodiment, determining preliminary source regions from candidate source region units and generating coded pulse infiltration sequences with mutually distinguishable time intervals for different preliminary source regions based on coding time conditions includes: screening candidate source region units that have candidate seepage paths with leachate collection nodes according to a candidate seepage path network to obtain preliminary source regions; determining multiple time interval levels for constituting coding based on the coding time conditions of the candidate seepage paths corresponding to each preliminary source region; generating multiple candidate coding sequences according to different arrangement orders of the multiple time interval levels; and assigning candidate coding sequences with different time interval orders to different preliminary source regions to obtain coded pulse infiltration sequences corresponding to each preliminary source region.

[0115] Starting from the leachate collection node, a reverse search can be performed along the candidate seepage path network to screen candidate source region units that can reach the collection node through continuous candidate directed connections.

[0116] First, candidate source units that consistently respond later than the sink node in multiple historical natural rainfall events can be excluded, because source responses should generally not lag behind their downstream receptor responses for an extended period.

[0117] Secondly, candidate source region units that do not have continuous candidate connections with the aggregation node and lack reasonable evidence of bypass can be excluded.

[0118] For the remaining candidate source areas, screening can be conducted by considering factors such as repeated initiation patterns across multiple historical natural rainfall events, the order of response start points, the sequence of pollutant appearances, and the recovery status. Candidate source areas with earlier initiation, consecutive candidate pathways, evidence of repeated events from multiple events, and a relatively stable order of pollutants can be prioritized for preliminary review.

[0119] In this embodiment, the time interval level refers to multiple time length levels set according to the coding time conditions of the candidate seepage path, used to distinguish the application times of adjacent coding pulses. The time interval level may include short time intervals, medium time intervals, and long time intervals, and two or more time interval levels may be set according to the number of initial source areas, the response speed of the candidate seepage path, and the length of the stable rainless period.

[0120] The time interval levels are not fixed values ​​uniformly set within the coal gangue dump, but are determined separately based on the coding time conditions of the candidate seepage paths corresponding to each preliminary source area. The coding time conditions include at least the distinguishable time interval between adjacent coding pulses and the protective time interval between two consecutive coding checks. The distinguishable time interval limits the time interval between adjacent coding pulses in the same coding pulse infiltration sequence, while the protective time interval limits the waiting time between two coding checks of different preliminary source areas.

[0121] Specifically, for a given preliminary source region, one or more candidate seepage paths are obtained from the preliminary source region to the corresponding leachate collection node, and the distinguishable time interval corresponding to each candidate seepage path is determined. When the same preliminary source region corresponds to multiple candidate seepage paths, the larger value among the distinguishable time intervals of each candidate seepage path can be selected as the base time interval for the preliminary source region to ensure that adjacent responses can still be distinguished after the encoded pulse propagates along any candidate seepage path to a node with a longer response duration.

[0122] After determining the basic time interval, a short time interval is set with a duration not less than the basic time interval. The short time interval is the minimum time interval level that constitutes the encoding. It should allow the response formed by the previous encoding pulse to enter a stable state or the trend of change to slow down significantly before the response formed by the next encoding pulse begins to appear, so as to avoid complete overlap between two adjacent responses.

[0123] Based on the short time interval, a medium time interval longer than the short time interval is set. The difference between the short time interval and the medium time interval should be such that after the candidate seepage path propagation, response broadening, and monitoring and acquisition discretization, they can still be identified as different time interval levels.

[0124] Further define a longer time interval than the intermediate time interval. The intermediate and long time intervals should also have sufficient difference to allow downstream nodes to distinguish between them based on the time relationship between adjacent response start points.

[0125] Short, medium, and long time intervals primarily represent relative time levels, rather than being limited to fixed absolute times. For example, for candidate seepage paths with rapid response and small response broadening, the three time interval levels can be set in the range of tens of minutes to several hours; for candidate seepage paths with slow response or significant local stagnation, each time interval level can be set to several hours or longer. The specific duration of each level is determined jointly by the response duration in historical natural rainfall events, the monitoring and acquisition cycle, and the actual response results of the path detection pulses.

[0126] When setting multiple time interval levels, the total duration of the coding sequence comprised of each time interval level should also be verified. The total duration of the coding sequence should not exceed the expected stable, rainless period that can be used for coding verification, in order to avoid interference from new natural rainfall before the complete coding process is finished.

[0127] After determining multiple time interval levels, multiple candidate coding sequences are generated according to the order of the different time interval levels. A candidate coding sequence represents the coding formed by arranging the time interval levels between multiple adjacent coding pulses in a predetermined order.

[0128] For example, short, medium, and long time intervals can be used to generate different candidate coding sequences such as "short-medium-long," "long-short-medium," "medium-long-short," "short-long-medium," and "medium-short-long." Each candidate coding sequence may contain the same time interval level, but the order of the time interval levels may differ, thus corresponding to different initial source regions.

[0129] When converting a candidate coding sequence into a coding pulse infiltration sequence, multiple coding pulses are applied sequentially within the initial source region, and the waiting time between adjacent coding pulses is controlled according to the time interval levels specified in the candidate coding sequence. For example, for a "short-medium-long" candidate coding sequence, the first coding pulse can be applied first, followed by the second coding pulse after a short time interval, then the third coding pulse after a medium time interval, and finally the fourth coding pulse after a long time interval. Thus, the three time interval levels need to be represented by at least four coding pulses.

[0130] The key to encoding identification is the relative order of adjacent pulse intervals, rather than the absolute time value of each time interval being exactly the same at each node. When the encoded pulse migrates in the coal gangue pile, the response time intervals recovered by each node may be prolonged or compressed due to differences in porosity, path diversion, and local water storage. As long as the relative order between short, medium, and long pulses can still be recovered, the node can be considered to have identified the corresponding encoding.

[0131] After generating multiple candidate coding sequences, candidate coding sequences that are prone to confusion or difficult to observe completely can be excluded according to preset coding screening conditions.

[0132] For example, when two candidate coding sequences differ only in the last time interval, and the monitoring window of the leachate collection node may not cover the last response, the two candidate coding sequences should not be assigned separately to the initial source region where response mixing may occur.

[0133] For example, if the total duration of a candidate coding sequence exceeds the expected stable rainless period, or if the last coding pulse reaches the leachate collection node after a new natural rainfall process has begun, then the candidate coding sequence is excluded.

[0134] The candidate coding sequences are also preferably those that show significant differences within the first or first two time intervals. Therefore, even if subsequent coding pulses fail to complete during the coding process due to natural rainfall, equipment malfunction, or safety reasons, the already formed partial time interval sequence can still serve as auxiliary information for identifying the initial source region.

[0135] After screening the candidate coding sequences, candidate coding sequences are assigned to different preliminary source regions. Preferably, for different preliminary source regions that are spatially adjacent, share at least part of the candidate seepage path, or point to the same leachate collection node, candidate coding sequences with different time interval orders should be assigned, so that the coding sequences assigned to the aforementioned preliminary source regions differ in the first or second time interval level, thereby improving the coding differentiation capability of downstream nodes.

[0136] For preliminary source areas that are far apart, have different candidate seepage paths, and point to different leachate collection nodes, the same candidate coding sequence can be reused because their responses will not mix at the same monitoring node.

[0137] For example, preliminary source area A and preliminary source area B are adjacent to each other, and both reach the same collection well via the infiltration point at the eastern slope toe and the eastern drainage ditch; preliminary source area C reaches another collection well via the western drainage ditch. In this case, a "short-medium-long" coding sequence can be assigned to preliminary source area A (set to 1 hour, 2 hours, and 4 hours respectively; after applying the first coding pulse to preliminary source area A, a second coding pulse is applied after an interval of 1 hour, a third coding pulse is applied after an interval of 2 hours, and finally a fourth coding pulse is applied after an interval of 4 hours, thus forming a coding pulse infiltration sequence with a time interval order of "short-medium-long"), and a "long-short-medium" coding sequence can be assigned to preliminary source area B. Since preliminary source area C does not share a path with A and B and points to different collection nodes, the "short-medium-long" coding sequence can be repeatedly assigned to preliminary source area C.

[0138] During actual coding verification, the coding application order for different preliminary source areas can be determined based on the protection time interval of the candidate seepage paths corresponding to each preliminary source area. For preliminary source areas that share a candidate seepage path or point to the same leachate collection node, it is not advisable to immediately apply the coding pulse infiltration sequence for the next preliminary source area before the coding response of the previous preliminary source area has subsided. Instead, the next coding verification should be implemented only after the relevant candidate seepage paths have met the protection time interval.

[0139] In addition, when the number of candidate coding sequences is less than the number of initial source regions that need to be distinguished from each other, the number of time interval levels or the number of coding pulses are increased to expand the candidate coding sequences; for initial source regions that do not have spatial adjacency, candidate seepage path sharing relationship and do not point to the same sink node, the same coding sequence is allowed to be reused.

[0140] Therefore, the coded pulse infiltration sequence corresponding to each preliminary source area includes at least the number of coded pulses, the order in which each coded pulse is applied, and the time interval order between adjacent coded pulses. The infiltration amount or duration of the coded pulses can be kept similar, so that the coded information is mainly carried by the time interval order, reducing the problem of difficulty in comparing different infiltration amounts after path attenuation. In the same coded pulse infiltration sequence, each coded pulse uses the same or within a preset allowable deviation range of water supply flow rate, duration, and infiltration amount; the time interval between adjacent coded pulses is uniformly measured by the difference between the start time or the end time of adjacent pulses, and remains consistent in the same round of coding verification.

[0141] Through the above process, each preliminary source region obtains a coded pulse infiltration sequence that is adapted to the response characteristics of its candidate seepage path and is distinguishable from other preliminary source regions that may have mixed responses. This provides a coding basis for identifying specific source regions and verifying candidate seepage paths based on the order of response time intervals recovered from each node.

[0142] In an exemplary embodiment, a corresponding coded pulse infiltration sequence is applied to the preliminary source region, and the infiltration responses of multiple nodes in each candidate seepage path are obtained. The response time interval order of each node is determined based on the infiltration responses. The verification result of the candidate seepage path is determined based on the continuous transmission state of the response time interval order in the candidate seepage path and the sequential relationship of the responses of each node. This includes: when it is confirmed that natural rainfall has stopped, applying multiple coded pulses sequentially to the corresponding preliminary source region according to the coded pulse infiltration sequence, and obtaining the infiltration responses generated by each node in the candidate seepage path; extracting the response corresponding to each coded pulse from the infiltration responses of each node. The system identifies points and determines the response time interval order of each node based on the time interval between adjacent response starting points of each coded pulse. Following the transmission direction of the initial source area, seepage migration nodes, and leachate collection nodes, the response time interval order and response sequence of each node are compared. When the same response time interval order appears consecutively along the candidate seepage path, and the response of the subsequent node is not earlier than that of the preceding node, a path confirmation result is generated. When the response time interval order does not appear consecutively along the candidate seepage path, and / or the response of the subsequent node is earlier than that of the preceding node, a path rejection result is generated. The path confirmation result or path rejection result is then used as the verification result for the candidate seepage path.

[0143] Before implementing coded infiltration, it should be confirmed that natural rainfall has ceased and the main monitoring nodes in the candidate infiltration path have reached a stable state. If the response from the previous natural rainfall or the previous coded test has not yet subsided, waiting should continue until the protection interval is met.

[0144] Select infiltration locations within the initial source area. Infiltration locations are preferably set in areas that started initiating earlier in historical natural rainfall, areas with concentrated surface fissures, areas with damaged overburden, areas with accumulated water infiltration, or areas with exposed coarse particles.

[0145] A flow-limiting boundary is set around the infiltration point to restrict the lateral diffusion of clean water on the surface and ensure that the clean water mainly enters the target initial source area. The flow-limiting boundary can be a temporary enclosure, shallow trench, flexible water-proof strip, or a ring boundary that is attached to the surface, but it should not damage the stable structure of the pile.

[0146] The infiltration area should avoid the free face of the slope, obvious slip cracks, and known unstable areas. The amount of clean water applied should be sufficient to generate a identifiable response near the source node, rather than aiming to generate a large flow rate at the end point, so as to avoid continuous surface runoff or a rapid increase in pore water pressure on the slope.

[0147] Each coded pulse can employ a fixed-duration water supply, a fixed-container batch water supply, or a controlled-flow water supply. After one pulse ends, wait according to the assigned time interval level before applying the next pulse. The waiting time can be timed from the start or end of the previous pulse, but a unified timing standard should be used within the same coded test.

[0148] During the coding process, the water accumulation status, surface runoff, near-source water content, downstream node response, and slope safety status within the infiltration boundary should be continuously monitored. Subsequent coding pulses should be terminated if the infiltration water crosses the flow restriction boundary, forms continuous surface runoff, causes abnormal slope displacement, or shows an abnormal increase in seepage flow at the slope toe.

[0149] If new natural rainfall arrives prematurely during the coding process, subsequent pulses should be stopped, and the already applied portion of the coding should be marked as incomplete coding. Only when this incomplete coding has formed a sufficiently discriminative time interval sequence and can be distinguished from the natural rainfall response can it be used as supplementary evidence and cannot directly replace the results of the complete coding review.

[0150] The coded pulse can manifest as different infiltration responses at different types of nodes. At nodes near the source of water content, it can manifest as an increase in water content, a change in dielectric state, or a change in temperature; at the infiltration point at the toe of the slope, it can manifest as an increase in infiltration flow, the start of outflow, or a short-term dilution of conductivity; in drainage ditches or collection wells with already high concentrations of leachate, the arrival of the clear water pulse can manifest as a short-term decrease in conductivity or the concentration of pollutants.

[0151] Therefore, the infiltration response is not limited to an increase in the monitored value. As long as the monitored data changes from a steady state to a continuously changing state, and the change time corresponds to the upstream pulse, it can be used as an coded response. When multiple response types exist for the same node, the response type with a clear starting point and good continuity can be selected first, and other response types can be used as auxiliary verification.

[0152] When a node receives the next pulse only after the previous pulse response has fully recovered, multiple response start points can be directly extracted. Candidate response start points should meet the persistence requirement. Abrupt changes that occur only at a single acquisition moment and do not continue afterward are not considered valid responses. Furthermore, the response time ranges of upstream pulses and upstream nodes should be considered for further filtering; changes significantly earlier than the corresponding upstream pulse cannot be attributed to this encoding.

[0153] After determining multiple valid response locations for the same node, compare the time durations between adjacent valid response start points and restore the time interval order. For example, if the first interval is significantly shorter than the second, and the second interval is significantly shorter than the third, the order can be restored to "short-medium-long".

[0154] When precise time is limited by the sampling frequency, only the time interval level needs to be determined, and the precise duration of the output is not required. Encoded recovery also does not require all nodes to obtain the same absolute interval. As the percolation propagates, the interval may change to some extent, but the relative order of size should be maintained.

[0155] For a candidate seepage path formed by the initial source region A, near-source node B, intermediate node C, slope toe node D, and converging node E, the response time intervals recovered by each node are compared in the order of the transmission directions from A to B, B to C, C to D, and D to E.

[0156] In addition to comparing the order of time intervals, the response sequence of each node is also compared. Generally, the nearest source node should respond first, followed by intermediate nodes, and the pooling node should respond last. The response time of a later-level node can be close to that of a earlier-level node, but after excluding time synchronization errors and residual responses from earlier stages, it should not consistently be earlier than the earlier-level node.

[0157] Different nodes do not need to use the same monitoring indicators. For example, near-source nodes can use changes in water content, intermediate nodes can use changes in temperature or flow rate, and terminal nodes can use changes in conductivity dilution. As long as each node can recover the same time interval sequence and the response order conforms to the spatial propagation direction, a cross-type coded response chain can be formed.

[0158] Critical nodes can include at least the near-source nodes corresponding to the initial source region, major path turning points, and target convergence nodes. Critical nodes should be determined based on the candidate path structure before coding trials. If a non-critical auxiliary node fails to recover coding, while other critical nodes form a continuous coding response chain, the candidate path can be retained, and the auxiliary node can be marked as a low-response node.

[0159] When the near-source nodes, each key seepage migration node, and the leachate collection node all recover the time interval order consistent with the coding applied to the initial source region, and the responses of each node appear sequentially according to the candidate path transmission direction, a path confirmation result is generated.

[0160] The path confirmation results indicate that there is an actual hydraulic transfer relationship between the corresponding preliminary source area and the sink node. Path confirmation does not require that the response amplitude of each node be the same, nor does it require that all nodes show the same water quality index changes. It only requires that the coding time interval order can be continuously transmitted along the key nodes and that the spatial response order is reasonable.

[0161] Before making a negative path result, it is necessary to check whether the monitoring equipment time is synchronized, whether there is any missing data at key nodes, whether there is any manual pumping or equipment flushing, and whether the previous natural rainfall or coded response has subsided.

[0162] When all key nodes in a candidate path exhibit infiltration responses, but the order of the recovered time intervals is inconsistent with the coding applied to the initial source region, a path rejection result can be generated. For example, if initial source region A applies "short-medium-long" coding, but the sink node recovers "long-short-medium" coding corresponding to another initial source region, then the response of the sink node cannot be attributed to A.

[0163] When the codes recovered by intermediate nodes and the pool node are inconsistent with each other, it indicates that the original candidate path may have split, mixed, or had node association errors at the intermediate position. A path negation result can be generated for the corresponding node connection, and the connection can be excluded in subsequent network updates.

[0164] When the response of the downstream node is stable earlier than that of the upstream node, and the interference from equipment time error, external water, previous residual response and other source area coding has been eliminated, it indicates that the connection of the node does not conform to the expected transmission direction, and a path negation result can be generated.

[0165] For node connections that are explicitly negative, subsequent reverse searches will no longer use that connection unless new monitoring evidence indicates that the reactor structure, drainage facilities, or site conditions have changed.

[0166] It should be noted that sensor malfunctions, communication interruptions, manual water pumping, equipment washing, and vehicle operation interference may occur during the monitoring process. Data with single-point abrupt changes and no corresponding changes in adjacent nodes are marked as isolated anomalies; data from equipment maintenance periods are excluded based on maintenance records.

[0167] For sudden changes in flow caused by artificial pumping, information on water quality changes during the same period can be retained, but the moment of the sudden change in flow should not be directly determined as the starting point of natural rainfall or coded response.

[0168] For nodes that experience prolonged data loss during critical encoding stages, instead of manually restoring the encoding using interpolation results, the node should be marked as unusable for decoding, and the experiment should be repeated in conjunction with other nodes or a new test should be conducted.

[0169] For a small number of missing continuous data points, the response stage of the node can be determined by combining the continuous change trend before and after the missing data, but a response starting point that does not exist in the original monitoring data cannot be added based on this.

[0170] In an exemplary embodiment, the candidate seepage path network is updated based on the verification results of the candidate seepage paths, and the preliminary source area is updated and re-encoded and verified based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue stockpile. This includes: adjusting the connection status of adjacent nodes in the candidate seepage path network according to the verification results of each candidate seepage path, wherein the connection status of adjacent nodes that generate path confirmation results is set to confirmed connection, and the connection status of adjacent nodes that generate path negation results is set to negation connection, to obtain an updated candidate seepage path network; updating the preliminary source area using the updated candidate seepage path network, and re-encoding and verifying the adjusted source area; updating the candidate seepage path network according to the re-encoding and verification results, and then switching to updating the preliminary source area using the updated candidate seepage path network, and re-encoding and verifying the adjusted source area, until a preset iteration stop condition is met, and outputting the final source area as the core source area of ​​leachate.

[0171] In this context, adjacent node connections refer to directed connections between two adjacent nodes in a candidate seepage path, following the direction of seepage propagation. For node connections where the encoded response time intervals are continuously transmitted between adjacent nodes, and the response of a later node is no earlier than that of a previous node, these connections are updated to confirmed connections. For node connections where each node responds, but the encoded time intervals are inconsistent, or where the response order still violates the path propagation direction after interference is eliminated, these connections are updated to negative connections.

[0172] When adjusting the connection state, each adjacent node pair can be used as the basic judgment object, rather than directly rejecting all node connections in a candidate seepage path before the entire candidate seepage path is fully confirmed. For example, for a candidate seepage path that sequentially includes a near-source node A, a seepage migration node B, a seepage migration node C, and a leachate collection node D, if near-source node A, seepage migration node B, and seepage migration node C all recover the response time interval order that matches the input code, but the leachate collection node D does not recover the corresponding code, the connections from A to B and B to C can be set as confirmed connections, and the connection from C to D can be set as a rejected connection, instead of rejecting A to B and B to C together. Thus, the updated candidate seepage path network can retain the local transit relationships that have been supported by the coded response and accurately represent the location where the coded response is interrupted.

[0173] After obtaining the updated candidate seepage path network, the current source region is updated based on the candidate source region units that have candidate seepage paths with the leachate collection nodes. This is the first update of the initial source region. Here, the current source region is a spatial object that updates with the iteration process: in the first loop, the current source region can be the initial source region selected from the original candidate source region units; in subsequent loops, the current candidate source region unit can be the source region formed after the previous update.

[0174] The current source region update involves updating the candidate seepage path network and then filtering candidate source region units that have candidate seepage paths with the leachate collection node by changing the connection relationships between adjacent nodes. Generally, when all candidate connections between a source region and the target leachate collection node are set as negative connections, and there is no path to the target leachate collection node via other confirmed connections, the source region can be excluded from the current review scope for that target leachate collection node. This exclusion means that the source region is no longer considered a core source region candidate for the current target collection node; it does not necessarily mean that the source region has no impact under other rainfall conditions or on other collection nodes.

[0175] After updating the source regions, the adjusted source regions are re-coded and verified. The re-coding and verification follows the aforementioned candidate seepage path verification process. It does not require the establishment of a different verification method. Instead, the initial source regions in the previous verification steps are replaced with the adjusted source regions in this round, and the nodes that need to be monitored and compared in this round are determined based on the updated candidate seepage path network.

[0176] Based on the path confirmation and rejection results obtained from the re-coding verification, the connection status of adjacent nodes in the candidate seepage path network is adjusted again, and the reachability between each adjusted source region and the target leachate collection node is redefined. Thus, each round of re-coding verification forms a new set of source regions and a new candidate seepage path network, and the new source regions become the objects of the next round of coding verification. This cyclical process allows previously large source regions to be progressively decomposed into smaller, more focused source regions. Through coding verification, regions that cannot contribute to the target leachate collection node are successively eliminated, causing the retained area to gradually converge towards a spatial range with a continuous coded response chain. From the overall iterative results, the suspected source region range for the target leachate collection node gradually converges into a smaller region that can contribute to the target leachate collection node through path confirmation.

[0177] The preset iteration stop conditions are used to determine whether the source area needs to be further subdivided and re-coded for verification. The recursive process can stop when at least one of the following iteration conditions is met: the source area reaches the preset treatment construction scale; further narrowing of the infiltration range fails to generate an identifiable response at the near-source monitoring node; or on-site stability or slope safety conditions do not allow for continued local infiltration verification.

[0178] After the recursion stops, the smallest confirmed area that can make an actual contribution to the target aggregation node through the confirmed path and cannot be further subdivided under the current monitoring and resolution conditions and governance scale will be identified as the core source area of ​​leachate.

[0179] After identifying the core source area of ​​leachate, priority can be given to measures such as covering layer repair, sealing of through fissures, upstream water interception, or local water accumulation control. Alternatively, local drainage, slow-release collection, or highly polluting coal gangue isolation measures can be implemented, or path interception, drainage modification, centralized collection, or local seepage prevention measures can be adopted.

[0180] When a major migration path receives leachate from multiple core source areas simultaneously, centralized collection or blocking of that path can achieve faster end-of-pipe emission reduction. However, long-term treatment should still be combined with infiltration control of upstream core source areas.

[0181] Taking a historical coal gangue stockpile as an example, the stockpile includes an upper old stockpile area, a middle coarse-particle new stockpile area, and a lower compacted area. Drainage ditches are set on the east and west sides of the stockpile, and the two drainage ditches eventually converge into the same collection well.

[0182] First, the storage yard was divided into four initial spatial units based on the terrain and actual drainage direction. The first initial spatial unit covers the upper old storage area, which contains both areas with intact overburden and areas with cracks and damage. Therefore, it was divided into two attribute sub-units based on the state of the overburden.

[0183] The second initial spatial unit covers the central coarse-grained region. The surface properties of this region are relatively uniform, but in multiple historical natural rainfall events, the water-bearing nodes on the east side have consistently responded earlier than those on the west side. Therefore, it is further divided based on the differences in dynamic response.

[0184] The third initial spatial unit is the lower compacted zone, which responds late after rainfall begins but recovers over a longer period after rainfall stops. The fourth initial spatial unit is the mixed deposit zone at the toe of the slope.

[0185] After attribute partitioning, dynamic splitting, and merging of regions with consistent response, multiple source regions are formed.

[0186] During the first moderate rainfall event, the water-bearing state of the upper fissure zone changed first, followed by outflow from the seepage point at the eastern toe of the slope, then increased flow in the eastern drainage ditch, and finally changes in conductivity and sulfate in the collection well.

[0187] During the second continuous rainfall event, the upper fissure zone was activated earliest again, forming the same nodal response sequence as the first time; the lower compaction zone was activated later in the rainfall, and the iron and manganese changes in the collection wells lasted for a longer period of time.

[0188] Based on the repeated response relationships in multiple events, a first candidate seepage path is established from the upper fracture zone through the eastern slope toe node and the eastern drainage ditch to the collection well; a second candidate seepage path is established from the middle coarse-grained eastern region through the eastern slope toe node to the collection well; and a third candidate seepage path is established from the lower compacted zone through the slope toe mixing zone to the collection well.

[0189] Historical natural rainfall calibration indicates that the first candidate path responds quickly and has a small broadening, the second candidate path has a moderate response speed and broadening, and the third candidate path responds slowly and has a long recovery time. Therefore, the first candidate path can use a relatively compact time interval level, while the third candidate path should use a generally longer time interval level.

[0190] During stable, non-rainfall periods, path detection pulses are first applied to the upper fracture zone. The near-source node quickly generates a response, indicating a valid infiltration location, followed by full coding. The near-source node, the eastern slope toe node, the eastern drainage ditch, and the catchment well all recover the same time interval sequence as the input, with responses appearing sequentially downstream, thus confirming the first candidate path.

[0191] After the first candidate path meets the protection time interval, the corresponding code is applied to the eastern region of the central coarse-grained area. The near-source node and the eastern slope toe node recover the correct code, but the catchment well does not show the code. Continuous monitoring revealed that the water content near the slope toe slowly decreased for a long period after coding, but no clear terminal response was formed. Therefore, this area was identified as a local stagnation area, rather than directly identified as the core source area of ​​the current catchment well.

[0192] After applying another code to the lower compacted zone, the sump well recovered the corresponding code, but the slope toe mixing zone node in the original candidate path did not respond. After verifying that the sensor was functioning normally, a bypass connection to be identified was established between the lower compacted zone and the sump well.

[0193] Historical data revealed the possible presence of an abandoned drainage pipe beneath the area. After adding a new monitoring node near the potential outlet of the abandoned drainage pipe, a new code was applied. Both the new node and the collection well regained the correct code, thus confirming that the lower compacted area reached the collection well via the buried drainage pipe.

[0194] The upper fracture zone was further subdivided. Based on the response differences between the two near-source monitoring locations, it was divided into an eastern fracture source zone and a western covered source zone. After verification using different codes, only the eastern fracture source zone formed a complete coded response chain reaching the catchment well. Therefore, the eastern fracture source zone was identified as the persistent core source zone, while the western covered source zone was excluded from the core source zone.

[0195] The lower compaction zone only activates under continuous rainfall conditions, but can reach the collection well via a bypass, and is therefore identified as a conditional contribution zone; the coded response of the central coarse-grained eastern region mainly stays near the slope toe, and is therefore identified as a retention and release zone; the eastern drainage ditch and buried drainage pipe are identified as the main migration paths.

[0196] Based on the identification results, priority can be given to covering and repairing the fissure source area on the east side and sealing the fissures. The buried drainage pipes corresponding to the lower compacted area should be repaired and collected independently. Local drainage and long-term monitoring should be set up in the central coarse particle retention area.

[0197] Based on the same inventive concept, this application also provides a coal gangue dump leachate source area identification system for implementing the above-mentioned coal gangue dump leachate source area identification method.

[0198] The solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the coal gangue dump leachate source area identification system provided below can be found in the limitations of the coal gangue dump leachate source area identification method described above, and will not be repeated here.

[0199] like Figure 2 As shown in the figure, this application provides a coal gangue dump leachate source area identification system 10, which includes: The source area division module 20 is used to obtain basic information about the coal gangue dump and dynamic response information of multiple monitoring nodes in multiple historical natural rainfall events, and to divide candidate source area units based on the basic information and dynamic response information. The time condition coding module 30 is used to establish a candidate seepage path network based on the response transmission relationship of candidate source area units, preset seepage migration nodes and preset leachate collection nodes in multiple historical natural rainfall events, and to determine the corresponding coding time conditions based on the response characteristics of each candidate seepage path. The infiltration sequence determination module 40 is used to determine the preliminary source region from the candidate source region units and generate a coding pulse infiltration sequence with mutually distinguishable time interval order for different preliminary source regions according to the coding time conditions. The response verification module 50 is used to apply the corresponding coded pulse infiltration sequence to the preliminary source area, obtain the infiltration response of multiple nodes in each candidate seepage path, determine the response time interval order of each node according to the infiltration response, and determine the verification result of the candidate seepage path according to the continuous transmission state of the response time interval order in the candidate seepage path and the response order relationship of each node. The source area determination module 60 is used to update the candidate seepage path network based on the verification results of the candidate seepage paths, and to update and re-encode and verify the preliminary source area based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump.

[0200] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0201] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0202] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, electronic devices, and computer storage media described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0203] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0204] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0205] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for identifying leachate source areas in coal gangue dumps, characterized in that, The method includes: Acquire basic information about coal gangue dumps and dynamic response information from multiple monitoring nodes during multiple historical natural rainfall events, and divide candidate source area units based on the basic information and the dynamic response information; Based on the response transmission relationship of the candidate source area units, preset seepage migration nodes and preset leachate collection nodes in multiple historical natural rainfall events, a candidate seepage path network is established, and the corresponding coding time conditions are determined according to the response characteristics of each candidate seepage path. Preliminary source regions are determined from the candidate source region units, and encoded pulse infiltration sequences with mutually distinguishable time intervals are generated for different preliminary source regions according to the encoding time conditions. A corresponding coded pulse infiltration sequence is applied to the preliminary source region to obtain the infiltration response of multiple nodes in each candidate seepage path. The response time interval order of each node is determined according to the infiltration response. The verification result of the candidate seepage path is determined according to the continuous transmission state of the response time interval order in the candidate seepage path and the response order of each node. The candidate seepage path network is updated based on the verification results of the candidate seepage paths, and the preliminary source area is updated and re-encoded and verified based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump.

2. The method for identifying leachate source areas in coal gangue dumps according to claim 1, characterized in that, The step of dividing candidate source region units based on the basic information and the dynamic response information includes: Based on the topographic and water catchment information in the basic information, the surface water catchment boundary of the coal gangue dump is determined, and the surface water catchment boundary is used as the spatial division boundary. The area enclosed by the surface water catchment boundary and where the surface water flows to the same drainage facility inlet is determined as an initial spatial unit, resulting in multiple initial spatial units. The initial space unit is partitioned according to the differences in the stacked attribute information within each initial space unit to obtain multiple attribute sub-units; Based on the differences in the dynamic response information of each attribute sub-unit in multiple historical natural rainfall events, the dynamic response relationship between adjacent attribute sub-units is determined; Adjacent attribute sub-units with consistent dynamic response relationships and pointing to the same seepage migration node are merged to obtain the candidate source region unit.

3. The method for identifying leachate source areas in coal gangue dumps according to claim 1, characterized in that, The step of establishing a candidate seepage path network based on the response transmission relationships of the candidate source area units, preset seepage migration nodes, and preset leachate collection nodes in multiple historical natural rainfall events includes: For each historical natural rainfall event, the response start points of the near-source nodes, the seepage migration nodes, and the leachate collection nodes of the candidate source area units are determined, and the response sequence between the nodes is determined based on the response start points. By screening recurring response sequence relationships from multiple historical natural rainfall events and combining them with the spatial location relationships between corresponding nodes or the connectivity relationships of drainage facilities, candidate directed connections are established from the earlier responding node to the later responding node. According to the transmission direction of the candidate directed connection, the near-source node, at least one of the seepage migration nodes and the leachate collection node are sequentially associated to form a candidate seepage path; The candidate seepage path network is established based on the node connection relationships between each candidate seepage path.

4. The method for identifying leachate source areas in coal gangue dumps according to claim 3, characterized in that, The step of determining the corresponding encoding time conditions based on the response characteristics of each candidate seepage path includes: Obtain the response duration and post-rainfall recovery status of multiple nodes in each candidate seepage path during the historical natural rainfall event; Based on the response duration of each node, the first target node with the longest response duration is determined from the corresponding candidate seepage paths. Combined with the response duration of the first target node and the monitoring acquisition cycle, the distinguishable time interval between adjacent coded pulses is determined. Based on the post-rainfall recovery status of each node, the second target node with the longest recovery time to a stable state is determined from the corresponding candidate seepage paths. Based on the time required for the second target node to recover to a preset stable state, the protection time interval between the two encoding verifications is determined. The distinguishable time interval and the protection time interval are determined as the coding time conditions for the corresponding candidate seepage paths.

5. The method for identifying leachate source areas in coal gangue dumps according to claim 1, characterized in that, The step of determining preliminary source regions from the candidate source region units and generating coded pulse infiltration sequences with mutually distinguishable time interval orders for different preliminary source regions according to the coding time conditions includes: Based on the candidate seepage path network, candidate source region units that have candidate seepage paths with the leachate collection node are screened to obtain the preliminary source region; Based on the coding time conditions of the candidate seepage paths corresponding to each of the preliminary source regions, multiple time interval levels for constituting the coding are determined; Multiple candidate coding sequences are generated according to different arrangement orders of the multiple time interval levels; Candidate coding sequences with different time intervals are assigned to different initial source regions to obtain the coding pulse infiltration sequence corresponding to each initial source region.

6. The method for identifying leachate source areas in coal gangue dumps according to claim 1, characterized in that, The process involves applying a corresponding coded pulse infiltration sequence to the initial source region, obtaining the infiltration responses of multiple nodes in each candidate seepage path, determining the response time interval order of each node based on the infiltration responses, and determining the verification result of the candidate seepage path based on the continuous transmission state of the response time interval order in the candidate seepage path and the response sequence of each node, including: Once it is confirmed that natural rainfall has stopped, multiple coded pulses are sequentially applied to the corresponding preliminary source area according to the coded pulse infiltration sequence, and the infiltration response generated by each node in the candidate infiltration path is obtained. Extract the response start point corresponding to each coded pulse from the infiltration response of each node, and determine the order of the response time intervals corresponding to each node based on the time interval between adjacent response start points of each coded pulse. According to the transmission direction of the initial source area, the seepage migration node and the leachate collection node, compare the response time interval order and response sequence of each node; When the same response time intervals occur consecutively along the candidate seepage path, and the response of the subsequent node is not earlier than that of the preceding node, a path confirmation result is generated. When the response time interval order does not occur consecutively along the candidate seepage path, and / or the response of the subsequent node is earlier than that of the preceding node, a path rejection result is generated; The path confirmation result or the path rejection result is determined as the verification result of the candidate seepage path.

7. The method for identifying leachate source areas in coal gangue dumps according to claim 6, characterized in that, The process of updating the candidate seepage path network based on the verification results of the candidate seepage paths, and updating and re-encoding the preliminary source area based on the updated candidate seepage path network, to obtain the core source area of ​​leachate from the coal gangue dump, includes: Based on the verification results of each candidate seepage path, the connection status of adjacent nodes in the candidate seepage path network is adjusted. Specifically, the connection status of adjacent nodes that generate path confirmation results is set to confirmed connection, and the connection status of adjacent nodes that generate path rejection results is set to rejection connection, thus obtaining an updated candidate seepage path network. The initial source region is updated using the updated candidate seepage path network, and the adjusted source region is re-encoded and verified. Based on the results of the re-encoding verification, the candidate seepage path network is updated, and the process is then moved to updating the preliminary source region using the updated candidate seepage path network. The adjusted source region is then re-encoded and verified until the preset iteration stop condition is met, and the final source region is output as the leachate core source region.

8. A system for identifying leachate source areas in coal gangue dumps, characterized in that, The system includes: The source area division module is used to obtain basic information about coal gangue dumps and dynamic response information of multiple monitoring nodes in multiple historical natural rainfall events, and to divide candidate source area units according to the basic information and the dynamic response information. The time-condition coding module is used to establish a candidate seepage path network based on the response transmission relationship of the candidate source area units, preset seepage migration nodes and preset leachate collection nodes in multiple historical natural rainfall events, and to determine the corresponding coding time conditions based on the response characteristics of each candidate seepage path. The infiltration sequence determination module is used to determine the preliminary source region from the candidate source region units and generate a coding pulse infiltration sequence with a mutually distinguishable time interval order for different preliminary source regions according to the coding time condition. The response verification module is used to apply a corresponding coded pulse infiltration sequence to the preliminary source region, obtain the infiltration response of multiple nodes in each candidate seepage path, determine the response time interval order of each node according to the infiltration response, and determine the verification result of the candidate seepage path according to the continuous transmission state of the response time interval order in the candidate seepage path and the response order of each node. The source area determination module is used to update the candidate seepage path network based on the verification results of the candidate seepage paths, and update and re-encode the preliminary source area based on the updated candidate seepage path network to obtain the core source area of ​​leachate from the coal gangue dump.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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