Early warning method for geological disasters in small watershed driven by rainfall distribution and rainwater infiltration

Abstract

The present application relates to the geological disaster early warning technical field, disclose rainfall distribution and rainwater infiltration collaborative driving small watershed geological disaster early warning method, utilize the real-time monitoring rainfall of monitoring area and the interception effect of the area tree and vegetation growth condition to real-time monitoring rainfall, calculate the rainfall of final reaching rock-soil body surface; According to the rainwater infiltration characteristics of soil body type of monitoring area and other parameters to determine the installation position of a plurality of monitoring sensors, according to the current soil saturation condition determined by a plurality of monitoring sensor response representation rainwater infiltration saturation depth; According to the current monitoring rainwater infiltration saturation depth, the experience saturation depth of monitoring soil body producing slope disaster, the permeability of soil body, evacuation reserved time and real-time reaching rock-soil body surface rainfall, calculate dynamic rainfall threshold and predict soil saturation instability time to carry out early warning. The present application improves the accuracy of small watershed surface flow geological disaster monitoring and early warning under extreme rainfall through rainfall distribution and rainwater infiltration collaborative driving.

Description

Technical Field

[0001] This invention relates to the field of geological disaster early warning technology, specifically to a method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration. Background Technology

[0002] In recent years, influenced by environmental changes, extreme heavy rainfall has led to a surge in shallow slope debris flows in previously low-risk areas, often occurring in densely vegetated regions. Under extreme rainfall, large amounts of rainwater accumulate in a short period within a small watershed. The infiltration and softening of the rainwater, combined with the impact of surface runoff, destabilizes the surface soil and rock, causing it to shovel and scrape downwards, exhibiting typical characteristics of slope debris flows. These disasters lack both a clear shear outlet and a large gully, exhibiting a pattern between flash floods and debris flows. The primary cause is the rapid saturation and instability of the loose, shallow soil and rock at the top of the slope due to the infiltration of large amounts of rainwater during extreme rainfall, resulting in a downward flow. The damage is mostly concentrated on the shallow surface of the soil and rock mass, typically only two to three meters deep. Extreme rainfall-induced geological disasters in small watersheds are characterized by small individual locations but numerous and widespread occurrences. There are no obvious signs of deformation before the disaster, and they mostly occur in traditionally low-risk micro-gully areas. They are characterized by strong suddenness in time, high randomness in space, and clustered occurrences in scale, making disaster monitoring and early warning difficult.

[0003] Rainfall monitoring and early warning is an effective means of reducing disaster losses. Traditional rainfall warnings primarily rely on rainfall thresholds, issuing warnings when rainfall intensity reaches a certain level (e.g., 50 mm / day). However, in applications involving early warning of geological disasters in small watersheds under extreme rainfall, this method has several major problems: First, traditional rainfall thresholds typically use short-duration heavy rainfall intensity as the core indicator, designed to capture floods or debris flows with significant runoff accumulation processes at the watershed scale. However, in extreme rainfall scenarios within small watersheds, disaster triggering is often not determined by a single peak rainfall intensity, but rather by a combination of factors including cumulative rainfall, prior soil moisture content, and underlying surface infiltration conditions. When rainfall intensity consistently fails to exceed the preset threshold, but prolonged low-intensity rainfall has gradually saturated the shallow soil and caused it to lose shear strength, the early warning system will experience widespread missed reports because the threshold has not been triggered. This is a typical dilemma of this type of disaster, where rainfall is not significant but it still causes widespread damage.

[0004] Secondly, extreme rainfall in small watersheds exhibits strong spatiotemporal variability, making it difficult for single-point rain gauge data to represent the true rainfall distribution within the entire micro-gully watershed. Traditional threshold-based early warning methods rely on limited station observations. When the rainfall center deviates from the monitoring station, even if high-intensity runoff and infiltration have occurred on local slopes, the system may still determine that the warning is safe because the station's records have not reached the threshold, leading to false or missed warnings. More importantly, the cluster-like nature of this type of disaster means that multiple micro-gullies may respond to the same rainfall event simultaneously. However, the catchment area, topographic slope, loose sediment thickness, and initial moisture content of each gully vary significantly, and a uniform, fixed rainfall threshold cannot characterize this differentiated response process under spatial heterogeneity.

[0005] Furthermore, traditional rainfall warnings essentially assume a fixed causal relationship between rainfall input and slope instability, but ignore the dynamic evolution of soil infiltration capacity during extreme rainfall. That is, when the surface soil is saturated, subsequent rainfall will quickly be converted into surface runoff, which not only exacerbates slope erosion, but may also form a transient saturation zone on the shallow surface and generate upper-layer water pressure. This process involves a strong coupling between the seepage field and the stress field, which cannot be characterized by a single indicator of rainfall intensity.

[0006] Therefore, when facing the application scenario of geological disaster early warning in small watersheds under extreme rainfall, relying solely on rainfall thresholds for early warning is neither able to capture the precursor information of the gradual deterioration of shallow soil in advance, nor can it achieve advanced response in time or accurate positioning in space. Summary of the Invention

[0007] This invention aims to provide a method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration. It considers the interception and distribution effects of different types and coverages of trees and vegetation on rainfall, combines the rainwater infiltration characteristics of different types of soil with the monitoring of the saturation depth of previous rainfall infiltration, and realizes the monitoring and early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration by calculating dynamic rainfall thresholds and predicting the soil saturation instability time. This solves the problem of poor early warning effect caused by the use of fixed thresholds in traditional early warning methods, and significantly improves the accuracy of monitoring and early warning of surface flow geological disasters in small watersheds under extreme rainfall.

[0008] The basic solution provided by this invention is: a small watershed geological disaster early warning method driven by the synergistic effect of rainfall distribution and rainwater infiltration, including: S1. By utilizing the real-time monitored rainfall in the monitoring area and the interception effect of the growth of trees and vegetation in the area on the real-time monitored rainfall, the mapping relationship between the real-time monitored rainfall and the rainfall reaching the surface of the rock and soil is determined, so as to calculate the final rainfall reaching the surface of the rock and soil based on the real-time monitored rainfall. S2. Based on the rainwater infiltration characteristics of the soil type in the monitoring area, the critical saturation depth of regional instability, and the evacuation allowance, determine the installation positions of several monitoring sensors that are buried sequentially from the ground line downwards. Based on the current soil saturation status characterized by the response of several monitoring sensors and the installation positions, determine the rainwater infiltration saturation depth. S3, at least one of the following methods should be used for early warning: Based on the currently monitored rainwater infiltration saturation depth, regional instability critical saturation depth, soil permeability characteristics, and evacuation allowance, the dynamic rainfall threshold on the surface of the soil and rock mass is calculated, and the dynamic threshold of monitored rainfall is obtained by using the mapping relationship in S1. Early warning is given by comparing the real-time monitored rainfall with the dynamic threshold of monitored rainfall. Based on the currently monitored rainwater infiltration saturation depth, regional instability critical saturation depth, soil permeability characteristics, and real-time rainfall reaching the soil surface, the soil saturation instability time is predicted; an early warning is issued by comparing the predicted soil saturation instability time with the disaster evacuation allowance.

[0009] The working principle and advantages of this invention are as follows: This invention addresses the actual causes of surface runoff geological disasters in small watersheds under extreme rainfall. It comprehensively considers the interception and distribution effects of different vegetation types and coverage levels on rainfall, and combines this with soil permeability properties and the saturation depth of previous rainfall infiltration to determine a dynamic early warning strategy for rainwater infiltration, achieving accurate early warning of surface runoff geological disasters in small watersheds under extreme rainfall. Its core advantages are: This invention considers the interception and distribution effects of different types and coverages of trees and vegetation on aerial rainfall. By monitoring actual rainfall, it obtains the actual rainfall amount acting on the soil and rock mass under a certain intensity of rainfall. This data is then matched with the actual causes of surface runoff geological disasters in small watersheds under extreme rainfall, improving the accuracy of early warning for this type of geological disaster from the data source. Specifically, the risks of surface runoff geological disasters in small watersheds under extreme rainfall often occur in areas with abundant vegetation. These disasters are mostly caused by the destruction of soil and rock by a large amount of rainwater infiltrating and saturating the soil and rock within a short period of time. Obviously, the growth of trees and vegetation varies in different monitoring areas. The same amount of rainfall (aerial rainfall) passing through different trees and vegetation will inevitably result in different amounts of rainwater reaching the ground and infiltrating into the soil. Therefore, unlike existing technologies that use real-time aerial rainfall monitoring and rainfall thresholds for early warning, this invention ultimately achieves early warning for surface runoff geological disasters in small watersheds under extreme rainfall by comparing the dynamic rainfall threshold reaching the surface of the soil and rock mass with the actual monitored rainfall through a mapping relationship. This approach offers higher scenario adaptability and more effective prediction.

[0010] This invention reconstructs the calculation method for rainwater infiltration saturation depth. By deploying a multi-layer sensor array vertically along the soil, the responses of each depth sensor directly indicate the actual arrival position of the infiltration front, enabling direct physical measurement of the rainwater infiltration saturation depth. This method is completely unaffected by the spatial variability of soil parameters and the generalization errors of traditional models. The measured infiltration saturation depth sequence can continuously track the movement trajectory and advance rate of the infiltration front, providing a reliable state input for dynamic threshold early warning. This upgrades early warning decisions from relying on static empirical thresholds to dynamic judgment based on real-time slope response status. The sensor's pre-buried depth is not determined based on conventional experience, but rather calculated by coupling the soil's permeability characteristics with the safe evacuation time required for residents' emergency evacuation. This aligns with the principle that the propagation rate of the infiltration front in shallow loose deposits decreases non-linearly with increasing burial depth. More importantly, it ensures that the response time difference between adjacent sensors precisely corresponds to the evacuation time. The measured rate of change in infiltration saturation depth directly indicates the emergency response window. Once the warning signal is triggered, it naturally provides an operational timeline, fundamentally resolving the core contradiction of when to issue a warning and whether there is enough time to evacuate. The deployment model is physically adjustable. By adjusting the input parameters, the optimal burial depth combination can be quickly recalculated to address differences in permeability and evacuation conditions in different areas. This enables differentiated and precise deployment of the monitoring system in different geological units and emergency scenarios, effectively curbing the underreporting and misreporting of small-scale cluster disasters.

[0011] This invention constructs two independent early warning paths based on measured rainwater infiltration saturation depth, and designs differentiated data fusion paths for each, addressing the two independent questions of whether and when a disaster will occur in emergency decision-making for shallow surface instability disasters in small watersheds. First, the measured infiltration saturation depth is used to calibrate the current water content of the slope. This is combined with soil infiltration characteristics, historical regional instability critical saturation depths, and evacuation allowance time to calculate the incremental rainfall on the soil surface required to trigger instability under the current conditions. Then, the mapping relationship between soil surface rainfall and measured aerial rainfall is used to transform this into a dynamic threshold for measured rainfall. This upgrades the static empirical threshold to a dynamic judgment strategy that adaptively adjusts according to the real-time soil saturation state of the slope, directly responding to the need to assess the probability of disaster occurrence under the current rainfall intensity. Secondly, by using measured infiltration saturation depth, integrating soil infiltration characteristics, historical regional instability critical saturation depths, and rainfall reaching the soil surface, the remaining time for the infiltration front to advance from its current location to the instability saturation depth is calculated. This time is then compared in real-time with resident evacuation time, mapping the slope response process to a time coordinate. This directly addresses the need to predict when a disaster will occur under the current rainfall intensity. Both paths share the same set of measured infiltration saturation depth data, approximating the instability criticality from both intensity and time perspectives. This ensures that the collaboratively outputted early warning information simultaneously possesses both disaster probability assessment and emergency response time scale, fully addressing the dual decision-making needs of whether to issue a warning and when to evacuate. Attached Figure Description

[0012] Figure 1 This is a flowchart illustrating the method for early warning of geological disasters in small watersheds driven by the coordinated action of rainfall distribution and rainwater infiltration, as provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the monitoring and early warning device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the infiltration saturation depth monitoring assembly provided in an embodiment of the present invention; Figure 4 This is a top view schematic diagram of the assembly of a grooved steel pipe and a moisture content sensor provided in an embodiment of the present invention; The markings in the accompanying drawings include: 1. Infiltration saturation depth monitoring assembly, 1-1. Grooved steel pipe, 1-2. Moisture content sensor, 1-3. Scale, 2. Display, 3. Rainfall monitoring module, 4. Audible and visual early warning module, 5. Solar panel, 6. Pole. Detailed Implementation

[0013] The following detailed explanation illustrates the specific implementation methods: The basic implementation examples are as follows: Figure 1 As shown: A method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration, including: S1. By utilizing the real-time monitored rainfall in the monitoring area and the interception effect of the growth of trees and vegetation in the area on the real-time monitored rainfall, the mapping relationship between the real-time monitored rainfall and the rainfall reaching the surface of the rock and soil is determined, so as to calculate the final rainfall reaching the surface of the rock and soil based on the real-time monitored rainfall. S2. Based on the rainwater infiltration characteristics of the soil type in the monitoring area, the critical saturation depth of regional instability, and the evacuation allowance, determine the installation positions of several monitoring sensors that are buried sequentially from the ground line downwards. Based on the current soil saturation status characterized by the response of several monitoring sensors and the installation positions, determine the rainwater infiltration saturation depth. S3, at least one of the following methods should be used for early warning: Based on the currently monitored rainwater infiltration saturation depth, regional instability critical saturation depth, soil permeability characteristics, and evacuation allowance, the dynamic rainfall threshold on the surface of the soil and rock mass is calculated, and the dynamic threshold of monitored rainfall is obtained by using the mapping relationship in S1. Early warning is given by comparing the real-time monitored rainfall with the dynamic threshold of monitored rainfall. Based on the currently monitored rainwater infiltration saturation depth, regional instability critical saturation depth, soil permeability characteristics, and real-time rainfall reaching the soil surface, the soil saturation instability time is predicted; an early warning is issued by comparing the predicted soil saturation instability time with the disaster evacuation allowance.

[0014] Specifically: In S1, the rainfall distribution is determined based on the growth of trees and vegetation in the monitoring area. The final amount of rainfall that reaches the ground (referring to the surface of the soil and rock mass) is calculated, specifically the amount that can infiltrate the soil and rock mass or generate surface runoff. The specific calculation formula is as follows:

[0015] In the formula, This indicates the amount of rainfall that ultimately reaches the surface of the soil or rock mass; This indicates real-time monitoring of rainfall; This indicates the amount of rainwater intercepted by trees during its fall. This indicates the amount of rainfall that is intercepted by surface vegetation such as grasses during its fall. This refers to the amount of rain that is intercepted by vegetation such as trees and herbs and eventually drips into or flows along the surface of the soil and rock mass.

[0016] The ; It is a constant, the specific value of which is determined according to the type of tree, and is roughly divided into four categories, such as: coniferous forests. =30%, broadleaf forest =20%, mixed forest =25%; when there are no tall trees =0.

[0017] The ; It is a constant, and its specific value is determined based on the coverage of vegetation such as herbaceous plants on the ground surface. It can be roughly divided into four cases, such as: when the coverage is high... =20%; medium coverage =12%; low coverage =4%; when only scattered herbs are present =0.

[0018] The ;because The values ​​are generally small, but the influencing factors are complex, therefore the constant... The specific values ​​are determined based on the overall density of vegetation such as trees and herbs in the monitoring area, such as when dense. =7%; when medium density =4%; when not dense =1%; sporadic distribution =0.

[0019] In summary: .

[0020] It should be noted that the values ​​of A, B, and C are obtained by statistical averaging of experimental or measured data reported in existing literature. For example, although coniferous forests have small leaves, their high density results in the highest rainwater interception rate. Broadleaf forests have large leaves but relatively low density, thus their interception rate is lower. Mixed forests fall in between. For herbaceous vegetation, the higher the coverage, the higher the interception rate. Coverage can be determined with reference to relevant standards, such as the "Technical Specification for Monitoring Forest Vegetation Status" GB / T 30363-2013 and the "Specification for Vegetation Coverage Products of Satellite Remote Sensing Image" GB / T 41280-2022. This embodiment S1 focuses on considering the rainfall distribution to construct a mapping relationship and calculate the rainfall that ultimately reaches the surface of the soil and rock mass, without limiting the specific data of A, B, and C.

[0021] In S2, the saturation depth of rainwater infiltration is monitored and used in S3 to participate in the calculation of real-time dynamic rainfall thresholds and predict instability time, so as to realize scientific and dynamic early warning of geological disasters such as landslides and surface flows caused by extreme rainfall.

[0022] Among them, starting from the critical saturation depth of regional instability and moving towards the ground line at intervals. Pre-embedded monitoring sensors are installed by placing the bottom sensor at the empirical saturation depth of the soil where slope hazards are likely to occur. Depth, then press upwards in sequence. Other sensors are deployed at intervals:

[0023] In the formula, Indicates the distance between two adjacent sensors, in mm; Parameter The saturated permeability of soil, in mm / h, represents the permeability characteristics of the soil; parameters The value represents the difference in water content between the soil under saturated and natural conditions. It is dimensionless and represents the soil's water-holding capacity and saturation capacity. (Parameter) The matrix suction of the soil, in mm, represents the soil's ability to absorb water and the magnitude of capillary action. The time interval, expressed in hours (h), is equal to the evacuation allowance. (This invention primarily targets geological disasters in small watersheds caused by extreme rainfall, specifically shallow slope runoff induced by extreme rainfall. The characteristics and types of these disasters are fixed. The evacuation allowance is mainly determined by the number of potentially affected people and their distance from the hazard point, and is not significantly related to the geological disaster itself. The specific figures are determined by geological personnel during equipment installation based on a comprehensive consideration of both the distance from the hazard point to the threatened individuals and the number of threatened individuals. For example, the more threatened individuals, the longer the safe evacuation time will be.) The greater the risk, the longer the evacuation will take; the closer the hazard point is to the threatened personnel, the longer the evacuation will take. The larger the capacity, the more leeway there is, and the evacuation time generally has a margin, satisfying the requirements for early warning and effective evacuation. Indicates the critical saturation depth for regional instability, in mm. Soil parameters. , and It can be obtained through indoor testing, and during the implementation of the project, it can be estimated by referring to tables based on the soil type.

[0024] For example: first determine the spacing between adjacent sensors, for example, parameters. =60mm / h, =0.2, =120mm, =2h, =2400mm, substituting into the above formula The calculation formula can determine the distance between two adjacent sensors. =630mm. After determining the spacing, during installation, install one sensor at the deepest point (z0), and then install other sensors sequentially upwards at 630mm intervals, until the distance between the topmost sensor and the ground line is less than or equal to... Up to this point. In this embodiment, one sensor is installed at a depth of 2400mm, one sensor at a depth of 1770mm, one sensor at a depth of 1140mm, and one sensor at a depth of 510mm, for a total of four sensors.

[0025] The determination of rainwater infiltration saturation depth based on the current soil saturation status and installation location, as characterized by the responses of several monitoring sensors, includes: Since the specific burial depth of each monitoring sensor (i.e., the moisture content sensor) has been determined previously, and each monitoring sensor is associated with its corresponding pre-buried depth, when a sensor detects that its moisture content has reached the soil's saturation moisture content, the current rainwater infiltration saturation depth is the sensor's pre-buried depth. For the moisture content sensor, a threshold method is adopted. The saturation moisture content of the soil in the area is determined in advance through laboratory methods, and this value is used as the sensor's alarm threshold. When the monitored value approaches or reaches this threshold, saturation can be determined.

[0026] The evacuation time varies depending on the specific hazard point and the needs of nearby residents. They are different, so the distances between the corresponding monitoring assemblies are also different. Therefore, this step... The calculation method involved in sensor layout can quickly adjust the sensor layout according to the current monitoring area, making the basis for early warning more refined and thus making the results more accurate.

[0027] S3 primarily addresses two issues: first, whether a disaster will occur given the current rainfall level, or at what rainfall level would a disaster occur—this is the early warning issue, focusing on the rainfall amount; second, how long will it take for a disaster to occur given the current rainfall level, focusing on the timing of the rainfall. Simultaneously addressing both issues means informing decision-makers or other stakeholders whether a disaster will occur or in how long it will occur.

[0028] Considering the redistribution of rainfall due to interception by vegetation such as trees and herbs in S1, and based on the principle of rainfall infiltration, rainwater gradually infiltrates and saturates the soil layer from top to bottom during a single rainfall event. For small watershed slope runoff geological hazards under extreme rainfall, when the loose surface soil of the slope reaches a certain saturation depth, it becomes unstable and slides downwards. Therefore, this invention proposes two early warning modes based on real-time monitoring of rainwater infiltration saturation depth: dynamic rainfall threshold early warning and soil saturation instability time prediction, to achieve real-time dynamic early warning of slope runoff geological hazards. The specific method is as follows: (a) Dynamic rainfall threshold early warning Based on the currently monitored rainwater infiltration saturation depth, combined with the regional instability critical saturation depth Z0 of the monitored soil (empirical depth derived from surveys or numerical simulations of similar disasters), the soil's permeability characteristics, and the disaster evacuation allowance time, (The disaster evacuation allowance time is the shortest time required for all threatened individuals to complete the evacuation before the slope becomes unstable.) The dynamic rainfall threshold is calculated using the following methods and steps: 1. Based on the growth of trees, herbs, and other vegetation on site, determine the specific values ​​of equipment constants A, B, and C, and simultaneously measure or estimate the permeability characteristics (i.e., soil parameters) of the corresponding soil. , , Based on soil parameters and statistical analysis or numerical simulation of similar disasters, the empirical depth Z0 for monitoring soil to cause slope hazards is determined; a pre-set evacuation allowance time is also included. .

[0029] II. Obtain the currently monitored soil rainwater infiltration saturation depth Z1, and combine it with the parameters determined in section I above, calculate the dynamic rainfall threshold that finally reaches the soil surface after being intercepted and redistributed by trees, etc., according to the following formula. :

[0030] Finally, based on the mapping relationship in S1, the monitoring rainfall threshold can be calculated using constants A, B, and C. ,as follows:

[0031] In practical use, when the real-time monitored rainfall is greater than or equal to An early warning will be issued immediately. Simultaneously, the rainfall monitoring threshold can be observed. It is a dynamic value that is related to the region's previous effective rainfall, that is, to the infiltration of previous rainfall.

[0032] The above methods and steps enable dynamic rainfall threshold early warning systems that consider rainwater infiltration saturation depth. To address the question of whether damage will occur under current rainfall intensity based on the existing soil moisture content, an early warning system is implemented that allows sufficient evacuation time for surrounding residents, thus achieving the desired early warning effect.

[0033] (II) Prediction of soil saturation instability time Based on the currently monitored rainwater infiltration saturation depth, combined with the empirical depth Z0 of the monitored soil that causes slope hazards and the current monitored rainfall, The specific methods and steps for calculating the slope saturation instability time are as follows: The first step is to obtain the current monitored rainfall. ; The second step is to obtain the currently monitored saturation depth of rainwater infiltration in the soil, Z1. Combining the soil parameters and the critical saturation depth of regional instability, the predicted soil saturation instability time t (i.e., instability after the current time t) is calculated using the following formula:

[0034] when Sometimes:

[0035] By combining the two modes above, dynamic early warning of disaster rainfall thresholds and prediction of instability time can be achieved for slope runoff based on rainfall infiltration saturation depth, enabling real-time and scientific early warning of disasters.

[0036] This is designed to predict how long a disaster will occur based on the current water content within the soil and the current rainfall per unit time. An early warning is issued when the time t is less than or equal to the preset evacuation time.

[0037] It should be noted that the above dynamic rainfall thresholds for the surface of soil and rock masses... The calculation basis for the soil saturation instability time t is that, for a specific potential hazard point, the total amount of rainfall required for its instability is a fixed value. Therefore, in a single rainfall event, to reach this fixed total rainfall, a rainfall intensity is required, which is the rainfall per unit time and the rainfall duration. The product of these two is the fixed total rainfall (the other coefficients in this invention are reductions caused by the soil's influence on rainfall infiltration). Based on this fundamental principle, the dynamic rainfall threshold early warning and soil saturation instability time prediction calculation processes in this invention are derived. The former fixes the rainfall time to determine the rainfall per unit time, while the latter fixes the rainfall per unit time to calculate how long it will take for the rainfall to reach the total rainfall required for the potential hazard point to become instable. Both processes share the same set of measured infiltration saturation depth data, approximating the instability threshold from both intensity conditions and time progression dimensions. The coordinated output ensures that the early warning information simultaneously possesses a disaster probability assessment and an emergency response time scale, fully responding to the dual decision-making needs of whether to issue an early warning and when to evacuate.

[0038] In this embodiment, a system is also constructed to execute the above-mentioned method for early warning of geological disasters in small watersheds driven by the coordinated distribution of rainfall and rainwater infiltration; the system includes at least one monitoring and early warning device installed in the monitoring area; like Figure 2 As shown, the monitoring and early warning device includes a pole 6 and an infiltration saturation depth monitoring assembly 1, a display 2, a rainfall monitoring module 3, an audible and visual early warning module 4, and a power supply module 5 arranged along the pole 6.

[0039] The infiltration saturation depth monitoring assembly 1 extends from the ground level down into the ground and is used to install several monitoring sensors 1-2; specifically, such as... Figure 3 As shown, the infiltration saturation depth monitoring assembly 1 includes a main body; scales 1-3 are provided along the height direction of the main body; several monitoring sensors are slidably installed on the main body in a single row along the height direction of the main body, and the spacing between the monitoring sensors is adjusted by sliding along the main body to adapt to the evacuation reserve time of different monitoring areas.

[0040] In this embodiment, the infiltration saturation depth monitoring assembly 1 includes a grooved steel pipe 1-1 (i.e., the main body), a moisture content sensor 1-2 (i.e., the monitoring sensor), and a scale 1-3 mounted on the grooved steel pipe 1-1. Figure 4 As shown ( Figure 3(Top view illustration) The moisture content sensor 1-2 is embedded in the grooved steel pipe 1-1, allowing the moisture content sensor 1-2 to slide and be fixed as needed on the grooved steel pipe 1-1 (the sliding and fixing methods can be achieved using existing technology). The scale 1-3 is used to calibrate the distance between multiple moisture content sensors 1-2. The distribution distance of the moisture content sensors 1-2 on the grooved steel pipe 1-1 is determined according to the formula in S2. The grooved steel pipe 1-1 is designed so that the spacing of the moisture content sensors 1-2 can be adjusted by sliding along the grooved steel pipe 1-1 to accommodate the withdrawal allowance time of different monitoring areas. This allows for more refined criteria for early warning, leading to more accurate results.

[0041] Display 2 is used to show rainwater infiltration information and early warning information. This includes information such as the saturation depth of rainwater infiltration, the location, operating status, and moisture content of each moisture sensor, whether the soil has reached saturation moisture content, and the dynamic rainfall threshold reaching the surface of the soil and rock mass. , With real-time monitoring of rainfall The comparison relationship, whether there is a warning, and the time t for soil saturation instability, etc.

[0042] The rainfall monitoring module 3 is used to obtain the real-time monitoring rainfall in the monitoring area and trigger the infiltration saturation depth monitoring assembly to run according to a preset method; in this embodiment, if rainfall is detected, the infiltration saturation depth monitoring assembly 1 will be triggered to run.

[0043] The audible and visual warning module 4 has a built-in calculation and warning program for calculating and issuing warning information. That is, it executes various calculation and warning processes in the above method and uses an existing controller to connect to the audible and visual alarm.

[0044] The power supply device 5 is used to power the entire device. The power supply device 5 is electrically connected to the infiltration saturation depth monitoring assembly 1, the display 2, the rainfall monitoring module 3, and the audible and visual early warning module 4, providing them with power. The specific connection method can follow existing technology. In this embodiment, a solar panel is used.

[0045] A portion of the pole 6 is buried underground to fix and connect the infiltration saturation depth monitoring assembly 1, the display 2, the rainfall monitoring module 3, the audible and visual early warning module 4, and the solar panel 5.

[0046] The small watershed geological disaster early warning method provided in this embodiment, driven by the coordinated action of rainfall distribution and rainwater infiltration, considers the interception and distribution effects of different types and coverages of trees and vegetation on rainfall. It combines the rainwater infiltration characteristics of different types of soil and monitors the saturation depth of previous rainfall infiltration. By calculating dynamic rainfall thresholds and predicting the soil saturation instability time, it achieves the coordinated action of rainfall distribution and rainwater infiltration to monitor and warn of geological disasters in small watersheds. This solves the problem of poor early warning effect caused by the use of fixed thresholds in traditional early warning methods, and significantly improves the accuracy of monitoring and early warning of surface flow geological disasters in small watersheds under extreme rainfall.

[0047] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics of the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration, characterized in that, include: S1. By utilizing the real-time monitored rainfall in the monitoring area and the interception effect of the growth of trees and vegetation in the area on the real-time monitored rainfall, the mapping relationship between the real-time monitored rainfall and the rainfall reaching the surface of the rock and soil is determined, so as to calculate the final rainfall reaching the surface of the rock and soil based on the real-time monitored rainfall. S2. Based on the rainwater infiltration characteristics of the soil type in the monitoring area, the critical saturation depth of regional instability, and the evacuation allowance, determine the installation positions of several monitoring sensors that are buried sequentially from the ground line downwards. Based on the current soil saturation status characterized by the response of several monitoring sensors and the installation positions, determine the rainwater infiltration saturation depth. S3, at least one of the following methods should be used for early warning: Based on the currently monitored rainwater infiltration saturation depth, regional instability critical saturation depth, soil permeability characteristics, and evacuation allowance, the dynamic rainfall threshold on the surface of the soil and rock mass is calculated, and the dynamic threshold of monitored rainfall is obtained by using the mapping relationship in S1. Early warning is given by comparing the real-time monitored rainfall with the dynamic threshold of monitored rainfall. Based on the currently monitored rainwater infiltration saturation depth, regional instability critical saturation depth, soil permeability characteristics, and real-time rainfall reaching the soil surface, the soil saturation instability time is predicted; an early warning is issued by comparing the predicted soil saturation instability time with the disaster evacuation allowance.

2. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1, characterized in that, The mapping relationship in S1 is as follows: In the formula, This indicates the amount of rainfall that ultimately reaches the surface of the soil or rock mass; This indicates real-time monitoring of rainfall; This indicates the amount of rainwater intercepted by trees during its fall. This indicates the amount of rainfall that is intercepted by vegetation during its fall. This refers to the amount of rain that is intercepted by trees and vegetation and eventually flows back into the surface of the soil and rock mass.

3. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 2, characterized in that, ,constant Determined based on tree type; ,constant Determined based on vegetation cover; ,constant Determined based on the overall density of trees and vegetation in the monitored area; The final determined mapping relationship between real-time monitored rainfall and rainfall reaching the surface of the soil and rock mass is as follows: 。 4. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1, characterized in that, In S2, starting from the critical saturation depth of regional instability and moving towards the ground line, the intervals are sequential. Pre-embedded monitoring sensors: In the formula, Indicates the distance between two adjacent sensors; parameter Soil saturation permeability; parameter The difference in water content between the soil under saturated and natural conditions; parameter The matrix suction of the soil; This indicates the time allotted for evacuation; This indicates the critical saturation depth for regional instability.

5. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1, characterized in that, In S2, determining the rainwater infiltration saturation depth based on the current soil saturation status and installation location indicated by the responses of several monitoring sensors includes: associating each monitoring sensor with its corresponding pre-buried depth. When in use, if a sensor detects that its moisture content has reached the saturated moisture content of the soil, the current rainwater infiltration saturation depth is the pre-buried depth of that sensor.

6. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1 or 3, characterized in that, In S3, the dynamic rainfall threshold on the surface of the soil and rock mass. The following formula is used for calculation: In the formula, Indicates the critical saturation depth of regional instability; Indicates the saturation depth of rainwater infiltration; Indicates the reserved evacuation time; parameters Soil saturation permeability; parameter The difference in water content between the soil under saturated and natural conditions; parameter This refers to the matrix suction of the soil.

7. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1 or 3, characterized in that, In S3, the predicted soil saturation instability time t is calculated using the following formula: In the formula, Indicates the critical saturation depth of regional instability; Indicates the saturation depth of rainwater infiltration; parameter Soil saturation permeability; parameter The difference in water content between the soil under saturated and natural conditions; parameter The matrix suction of the soil; This indicates the amount of rainfall that ultimately reaches the surface of the soil or rock mass.

8. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1, characterized in that, In S3, an early warning is issued when the real-time monitored rainfall is greater than or equal to the real-time rainfall dynamic threshold; an early warning is also issued when the predicted instability time is less than or equal to the disaster evacuation allowance time.

9. The method for early warning of geological disasters in small watersheds driven by the synergistic effect of rainfall distribution and rainwater infiltration as described in claim 1, characterized in that, A system is constructed to implement a small watershed geological hazard early warning method driven by the coordinated effects of rainfall distribution and rainwater infiltration; the system includes at least one monitoring and early warning device installed in the monitoring area; The monitoring and early warning device includes a pole and an infiltration saturation depth monitoring assembly, a display, a rainfall monitoring module, an audible and visual early warning module, and a power supply module installed along the pole. The infiltration saturation depth monitoring assembly extends from the ground line into the ground and is used to install several monitoring sensors. The rainfall monitoring module is used to acquire real-time rainfall data in the monitoring area and trigger the infiltration saturation depth monitoring assembly to operate according to a preset method. The audible and visual early warning module has built-in calculation and early warning programs for calculating and issuing early warning information. The display is used to show rainwater infiltration information and early warning information.

10. The method for early warning of geological disasters in small watersheds driven by the coordinated action of rainfall distribution and rainwater infiltration as described in claim 9, characterized in that, The infiltration saturation depth monitoring assembly includes a main body; a scale is set on the main body extending from the ground line to the underground; several monitoring sensors are installed on the main body in a single row and can be slidably mounted along the main body extending from the ground line to the underground. The spacing of the monitoring sensors can be adjusted by sliding along the main body to adapt to the evacuation allowance time of different monitoring areas.

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