An experimental device based on underground storage and drainage space of pit bottom of open coal mine

Abstract

The application discloses an experimental device based on an underground water storage and drainage space of a pit bottom of an open coal mine, and belongs to the technical field of open mine mining hydrogeological engineering and indoor simulation. The device comprises a sand box main body, an underground water simulation system, a rainfall simulation system, an underground water storage and drainage space simulation structure and a monitoring and drainage control system. The first and second high water head water tanks and the first and second low water head water tanks are used for simulating and controlling underground water flow, and an adjustable shower is used for simulating rainfall. The simulation structure is internally provided with a concrete anti-seepage wall, wherein a filter layer and a water storage medium are filled from bottom to top, a water diversion channel is arranged at the bottom, and a water pumping filter pipe penetrating through the anti-seepage wall and extending into the water storage medium is arranged at the upper portion. The application can accurately simulate complex working conditions coupled by multiple factors, realize synchronous monitoring of multiple parameters such as seepage and water level, provide reliable experimental basis for medium selection, structure optimization and drainage scheme making of the underground water storage and drainage space, and effectively guide engineering practice.

Description

Technical Field

[0001] This invention relates to the field of open-pit mining hydrogeological engineering and indoor simulation experiment technology, and in particular to an experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine. Background Technology

[0002] Open-pit coal mine drainage is a core engineering aspect for ensuring safe mining operations and maintaining the stability of the internal spoil heap base. With the increasing intensity of open-pit coal mining and the widespread adoption of internal spoil heap technology, the space at the bottom of the mining area is continuously compressed due to factors such as the forward movement of the internal spoil heap and adjustments to the mining interface. The limitations of traditional surface sump pump drainage systems are becoming increasingly apparent. Statistics show that approximately 60% of open-pit coal mines in northern my country face the problem of internal spoil heaps encroaching on the pit bottom space. After space compression, the water storage capacity of traditional surface sump pump drainage systems can decrease by 30%-50%, increasing the probability of flooding the steps during heavy rain to over 40%. This results in an average downtime of 2-3 days per mining face, and uneven settlement of the internal spoil heap base exceeding 15mm, causing not only huge economic losses but also significant safety hazards.

[0003] Underground storage and drainage space technology, which integrates water storage and drainage by arranging porous media such as gravel and rubble at the bottom of the pit, utilizes the pores of the media to store water and rapidly drains it through a pumping system, has become an important research direction for solving the problem of insufficient space at the bottom of pits. Currently, the selection of media, the design of the filter layer, and the optimization of the water diversion channel are the key technologies for underground storage and drainage spaces, but there is a lack of indoor physical simulation devices that can reproduce complex working conditions.

[0004] Existing technologies suffer from three major shortcomings: First, they lack the ability to perform multi-condition coupled simulations, failing to accurately reproduce the synergistic effects of factors such as groundwater flow velocity, rainfall intensity, and formation medium type. Second, the structural parameters of the experimental device (such as the gradation of the filter layer and the arrangement of the pumping filter pipes) lack standardized design, resulting in insufficient repeatability and reliability of experimental results. Third, the data acquisition system is incomplete, making it difficult to achieve synchronous monitoring of seepage fields, pressure fields, and water level changes during storage and drainage processes, thus preventing the experimental data from providing accurate parameter support for on-site engineering. Therefore, developing a well-structured, precisely controlled, and comprehensively monitored indoor experimental device is of great significance for promoting the engineering application of underground storage and drainage space technology. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine.

[0006] The technical solution adopted in this invention is: an experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine, the key technical points of which include: The system includes: a sandbox body filled with formation medium; a groundwater simulation system comprising a first high-head tank, a second high-head tank, a first low-head tank, and a second low-head tank, wherein the first high-head tank and the second high-head tank are connected by pipelines, and the second high-head tank, the first low-head tank, and the second low-head tank are each connected to the sandbox body via independent pipelines; a rainfall simulation system including a sprinkler system located above the sandbox body; and an underground storage and drainage space simulation structure disposed within the sandbox body. The interior includes a concrete cutoff wall, a filter layer filled within the concrete cutoff wall, a water storage medium, and a water intake channel and a pumping filter pipe located within the area enclosed by the concrete cutoff wall. The water intake channel is laid below or embedded in the filter layer, and the inlet end of the pumping filter pipe is located within the water storage medium, with its pipe body passing through the concrete cutoff wall to connect to the outside. The monitoring and drainage control system includes a water level gauge located on the side wall of the sand box body and a first drainage hole and a second drainage hole located at the bottom of the sand box body.

[0007] In the above scheme, the inlet of the water pumping filter pipe is at a higher height than the arrangement height of the water diversion channel.

[0008] In the above scheme, the concrete anti-seepage wall is set along the inner perimeter and bottom of the sand box body.

[0009] In the above scheme, the spraying device is a shower head, which is connected to the water source tank through a water supply pipeline.

[0010] In the above scheme, the filter layer is composed of multiple layers of gravel or rubble with different particle sizes.

[0011] The beneficial effects of this invention are as follows: This experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine enables wide-range control of groundwater flow velocity, rainfall intensity, and water storage medium type, and can reproduce more than 90% of the actual hydrological conditions at the bottom of an open-pit coal mine, solving the problem of the single simulation scenario of existing devices; the structural design is scientific and reasonable, with layered and graded filter layers meeting hydrogeological filter requirements, and the arrangement of water diversion channels and spiral pumping filter pipes improving water collection and drainage efficiency; the concrete anti-seepage wall ensures the stability of experimental boundary conditions, resulting in high reliability of experimental results; integrated monitoring and analysis, with the data acquisition system realizing simultaneous monitoring and real-time transmission of multiple parameters, and subsequent analysis software can be used to complete visualization processing and quantitative calculation, providing direct data support for parameter optimization; strong versatility, adaptable to different types of open-pit coal mine geological conditions (sand, silty clay, gravel layers), and targeted experimental research can be carried out by adjusting the medium type and structural parameters; it simulates the use of underground storage and drainage space under different working conditions, and analyzes and compares it with the water storage media that may be used in actual engineering to determine the appropriate scheme under different working conditions. To ensure successful practical application, preliminary testing was conducted, taking into account multiple dimensions. Compared to traditional methods, underground storage and drainage requires less pit space and does not require frequent relocation due to changes in the mining, stripping, and drainage locations, offering a permanent solution. Furthermore, it can serve as a stable water storage source in practical applications, making it a suitable option for water-scarce open-pit coal mines. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the underground storage and drainage space experimental device in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the experimental apparatus in an embodiment of the present invention; The numbers in the diagram are explained as follows: 1 is the first high-head water tank, 2 is the water valve, 3 is the second high-head water tank, 4 is the first electronic water level gauge, 5 is the shower head (rainfall simulation device), 6 is the first perforated permeable plate, 7 is the second perforated permeable plate, 8 is the second electronic water level gauge, 9 is the first low-head water tank, 10 is the second low-head water tank, 11 is the first drain hole, 12 is the water level gauge, 13 is the second drain hole, 14 is the water source tank, 15 is the soil sample added to the stratum, 16 is the concrete anti-seepage wall, 17 is the reverse filter layer, 18 is the water diversion channel, 19 is the water storage space medium, and 20 is the pumping filter pipe. Detailed Implementation

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the following description is provided in conjunction with the accompanying drawings. Figure 1 , Figure 2 The present invention will be further described in detail below with reference to specific embodiments.

[0015] like Figure 1 and Figure 2 As shown in the figure, the experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine is provided in this embodiment. The experimental device simulates the flow of groundwater and rainfall replenishment at the bottom of an open-pit coal mine through a sand box. It mainly includes a sand box body, a groundwater simulation system, a rainfall simulation system, an underground storage and drainage space simulation structure, and a monitoring and drainage control system.

[0016] The sand box body 15 provided in this embodiment is a rectangular box structure, the interior of which is filled with geological media to simulate the rock and soil structure of the bottom and steps of an open-pit coal mine. At least one side wall of the sand box body 15 is provided with a permeable area.

[0017] The groundwater simulation system of this embodiment is used to form and control groundwater flow within the sandbox body 15. The system includes a first high-head water tank 1 and a second high-head water tank 3 located on one side of the sandbox body 15, and a first low-head water tank 9 and a second low-head water tank 10 located on the other side of the sandbox body 15. The first high-head water tank 1 and the second high-head water tank 3 are connected by pipelines, and water valves 2 are also installed on these pipelines. The first high-head water tank 1 and the second high-head water tank 3 are each connected to inlets at different heights on one side wall of the sandbox body 15 via independent pipelines. The first low-head water tank 9 and the second low-head water tank 10 are each connected to outlets at different heights on the other side wall of the sandbox body 15 via independent pipelines. By adjusting the water level difference between the tanks, groundwater flow fields with different velocities and directions can be simulated.

[0018] The rainfall simulation system in this embodiment is used to simulate the replenishment of the pit bottom by atmospheric precipitation. The system includes a shower head 5 mounted above the sandbox body 15. The shower head 5 is connected to an external water supply tank 14 via a water supply pipeline. An adjusting valve is installed on the water supply pipeline, which can control the amount of water sprayed per unit time, thereby simulating different rainfall intensities.

[0019] The underground storage and drainage space simulation structure of this embodiment is built into the sand box body 15 to simulate underground storage and drainage structures in actual engineering. Specifically, it includes: a concrete cutoff wall 16, a filter layer 17, a water storage medium 19, a water diversion channel 18, and a pumping filter pipe 20. The concrete cutoff wall 16 is poured around the perimeter and bottom of a preset area inside the sand box body 15 to form a closed simulated boundary. The filter layer 17 is filled at the bottom of the area enclosed by the concrete cutoff wall 16 and is made of multiple layers of gravel or rubble of different particle sizes laid according to a set gradation. The water storage medium 19 is filled above and around the filter layer 17 and is usually made of gravel or crushed stone with high porosity. The water diversion channel 18 is laid at the bottom of the area enclosed by the concrete cutoff wall 16 and is located below or embedded in the filter layer 17 to collect and guide groundwater that seeps into the area.

[0020] The water pumping filter pipe 20 is arranged in the upper area of ​​the water storage space medium 19, with its inlet end buried in the water storage space medium 19 and its inlet height higher than the laying height of the water diversion channel 18; the outlet end of the water pumping filter pipe 20 passes through the concrete anti-seepage wall 16 or the box wall of the sand box body 15 and is connected to the external drainage pipe.

[0021] The monitoring and drainage control system used in this embodiment is used to monitor the experimental process and control drainage. It includes a water level monitoring component, a permeable and anti-clogging component, a drainage component, and a data acquisition module (not shown in the figure). The water level monitoring component includes a first electronic water level gauge 4 installed on the first high-head water tank 1, a second electronic water level gauge 8 installed on the first low-head water tank 9, and a sand tank water level gauge 12 installed on the side wall of the sand tank body 15, used to monitor the water level in the sand tank in real time. The permeable and anti-clogging component of this embodiment is installed on the side wall of the sand tank body 15 with a permeable area, including a first perforated permeable plate 6 and a second perforated permeable plate 7, with a filter screen laid on the inner surface of each perforated permeable plate to prevent internal media blockage.

[0022] The drainage component of this embodiment includes a first drainage hole 11 and a second drainage hole 13 located at the bottom of the sand box body 15, and a water pump (not shown separately in the figure) connected to the water pumping filter pipe 20.

[0023] This embodiment can connect to each water level gauge via a data acquisition module to collect data such as water level and time, which can then be transmitted to a computer for real-time display and analysis. This embodiment does not limit the data acquisition module; users can select a data acquisition device as needed, such as the HC-RTU3000 three-parameter monitoring device.

[0024] The working principle of the experimental setup in this embodiment is as follows: During the experiment, soil samples were first filled into the sand box body 15 according to the strata sequence to construct a simulated open-pit coal mine step distribution. Then, the groundwater simulation system was activated, and a stable underground seepage field was formed in the sand box by adjusting the water level of each tank. Rainfall was simulated using a sprinkler 5 to control the water volume and replenish the groundwater. Water flowing into the simulated pit bottom area partially seeped into the underground storage and drainage space composed of the filter layer 17 and the water storage medium 19, and was collected through the water intake channel 18. The water level was controlled by the first electronic water level gauge 4 and the second electronic water level gauge 8 in conjunction with the water pump, and the water level in the sand box was monitored in real time by the water level gauge 12 on the side of the sand box. When drainage was required, the intelligent water pump was activated, and the water was drawn out through the water pumping filter pipe 20 and discharged through the first drainage hole 11 or the second drainage hole 13, simulating the pumping process in actual engineering. By simulating the use of the underground storage and drainage space, the water storage effect under different particle sizes was tested, and it was determined whether the use of the water intake and drainage blocks met the requirements for rapid water storage and prevention of the pit bottom from being soaked by accumulated water.

[0025] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine, characterized in that, include: The main body of the sand box (15) is filled with the formation medium; The groundwater simulation system includes a first high head water tank (1), a second high head water tank (3), a first low head water tank (9), and a second low head water tank (10). The first high head water tank (1) and the second high head water tank (3) are connected by pipelines. The second high head water tank (3), the first low head water tank (9), and the second low head water tank (10) are respectively connected to the sand box body (15) through independent pipelines. The rainfall simulation system includes a spray device (5) located above the sand box body (15); The underground storage and drainage space simulation structure is set inside the sand box body (15) and includes a concrete anti-seepage wall (16), a filter layer (17) filled in the concrete anti-seepage wall (16) and a water storage medium (19), as well as a water diversion channel (18) and a pumping filter pipe (20) set in the area enclosed by the concrete anti-seepage wall (16). The water diversion channel (18) is laid below the filter layer (17) or embedded in the filter layer (17). The water inlet end of the pumping filter pipe (20) is located in the water storage medium (19), and its pipe body passes through the concrete anti-seepage wall (16) to connect to the outside. The monitoring and drainage control system includes a water level gauge (12) located on the side wall of the sand box body (15) and a first drainage hole (11) and a second drainage hole (13) located at the bottom of the sand box body (15).

2. The experimental device based on the underground storage and drainage space at the bottom of an open-pit coal mine as described in claim 1, characterized in that, The inlet of the water pumping filter pipe (20) is higher than the arrangement height of the water diversion channel (18).

3. The experimental apparatus based on the underground storage and drainage space at the bottom of an open-pit coal mine according to claim 1, characterized in that, The concrete anti-seepage wall (16) is set around the inside and bottom of the sand box body (15).

4. The experimental apparatus based on the underground storage and drainage space at the bottom of an open-pit coal mine according to claim 1, characterized in that, The spray device (5) is a shower head, which is connected to the water source tank (14) through a water supply pipeline.

5. The experimental apparatus based on the underground storage and drainage space at the bottom of an open-pit coal mine according to claim 1, characterized in that, The filter layer (17) is composed of multiple layers of gravel or rubble of different particle sizes.

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