Early warning method for karst collapse based on the dissolution rate of the rock on the cave roof.

Abstract

This invention provides a karst collapse early warning method based on the dissolution rate of the cave roof rock, belonging to the field of geological disaster monitoring and early warning technology. This karst collapse early warning method based on the dissolution rate of the cave roof rock includes: constructing an underground cave simulation model, which includes initial values ​​of various preset indicators and time-series-based indicator change conditions; inputting the stress of the strata above the underground cave into the underground cave simulation model; obtaining the state of the underground cave roof after a preset time period; determining the real-time stress of the overlying strata of the underground cave simulation model when the underground cave roof is in a collapsed state; and determining the critical value of the roof thickness of the underground cave simulation model based on the real-time stress of the overlying strata. This method accurately simulates the changes in the cave roof under different conditions, thereby improving the accuracy of predicting potential collapse risks. This method considers the time-series indicator change conditions, enabling dynamic monitoring of the cave roof state.

Description

Technical Field

[0001] This invention relates to the field of geological disaster monitoring and early warning technology, and in particular to a karst collapse early warning method based on the dissolution rate of the rock on the roof of a cave. Background Technology

[0002] Karst collapse, a global geological hazard, is particularly common in countries and regions with widespread karst landforms. China, with karst areas covering approximately one-third of its land area, experiences a particularly prominent phenomenon of karst collapse. This collapse is typically caused by the inability of the roof of underground karst caves to support the overlying load, leading to surface subsidence or the formation of sinkholes, posing a serious threat to building safety, infrastructure integrity, and people's lives.

[0003] Karst collapse disasters are characterized by their suddenness and insidious nature, making surface monitoring insufficient for early warning. Traditional surface movement and deformation monitoring methods have limited effectiveness in predicting these disasters because the surface often does not show obvious displacement before collapse. Furthermore, while geophysical exploration methods can detect the existence and approximate location of underground caverns, these methods are costly, their accuracy is affected by various factors, and they cannot provide continuous monitoring data.

[0004] The roof of a karst cave is a crucial structure supporting the overlying strata, and its thickness directly affects whether karst collapse will occur. With the action of groundwater, the rock in the cave roof is continuously eroded, leading to a gradual decrease in roof thickness, significantly reducing its strength and stability, and consequently decreasing its load-bearing capacity. Once the load-bearing capacity of the cave roof is insufficient to support the load of the overlying strata, collapse will occur. Therefore, how to effectively monitor changes in the thickness of the cave roof and use this information for early warning of collapse has become an urgent technical problem to be solved. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for real-time monitoring of the thickness and stress changes of the roof rock of underground karst caves, in order to predict and warn of possible karst collapse times and the thickness of the roof rock at the time of collapse.

[0006] Firstly, a karst collapse early warning method based on the dissolution rate of the rock on the roof of a karst cave is provided, including:

[0007] A simulation model of an underground karst cave is constructed, which includes initial values ​​of various preset indicators and time-series-based indicator change conditions; the indicator change conditions include the roof erosion rate.

[0008] The stress of the strata above the underground cavern is input into the simulation model of the underground cavern and run.

[0009] The state of the underground cave roof after a preset time period is obtained;

[0010] When the roof of the underground cavern is in a collapsed state, determine the real-time stress of the overlying strata of the underground cavern simulation model;

[0011] Based on the real-time stress of the overlying strata, the critical value of the top plate thickness of the underground karst cave simulation model is determined.

[0012] Furthermore, the real-time stress of the overlying stratum is the sum of the real-time stress of the roof of the underground cavern and the stress of the stratum.

[0013] Furthermore, the real-time stress of the overlying strata is obtained using the following formula:

[0014] h = h0 - η t (1)

[0015]

[0016] Where h is the real-time thickness of the top plate, h0 is the initial thickness of the top plate, η is the dissolution rate, t is the elapsed time, γ is the unit weight of the top plate, P is the real-time stress of the overlying strata, and γ i Let h be the unit weight of the i-th stratum. i Let be the thickness of the i-th stratum.

[0017] Furthermore, the initial values ​​of each preset index include the initial thickness of the cave roof, the specific weight of the roof, the elastic modulus, Poisson's ratio, tensile strength, and shear strength.

[0018] Furthermore, the method for obtaining the top plate dissolution rate includes:

[0019] Obtain the thickness values ​​of the roof slabs of two underground karst caves at the same location at two different time points;

[0020] The erosion rate of the top plate is determined based on the two top plate thickness values ​​and the time interval between the two time points.

[0021] Furthermore, it also includes triggering an early warning when the cave is in a collapsed state.

[0022] Secondly, a karst collapse early warning system based on the dissolution rate of the rock on the roof of a karst cave is provided, including:

[0023] A construction module is used to construct an underground karst cave simulation model, which includes initial values ​​of various preset indicators and time-series-based indicator change conditions.

[0024] The running module is used to input the stress of the strata above the underground cave into the simulation model of the underground cave for operation;

[0025] The acquisition module is used to obtain the state of the roof of the underground cave after a preset time period;

[0026] The determination module is used to determine the real-time stress of the overlying strata of the underground karst cave simulation model when the roof of the underground karst cave is in a collapsed state.

[0027] The determination module is also used to determine the critical value of the top plate thickness of the underground karst cave simulation model based on the real-time stress of the overlying strata.

[0028] Thirdly, a computer-readable storage medium is provided, storing a program or instructions that, when executed on a computer, cause the computer to perform the karst collapse early warning method based on the dissolution rate of the rock on the roof of a karst cave as described in the above technical solution.

[0029] Fourthly, an electronic device is provided, comprising: a processor coupled to a memory.

[0030] The processor is used to read and execute the computer program stored in the memory to implement the karst collapse early warning method based on the dissolution rate of the cave roof rock as described in the above technical solution.

[0031] The embodiments of the present invention have the following advantages or beneficial effects:

[0032] 1. By constructing a simulation model of underground karst caves and combining it with actual geological stress conditions, the changes in the cave roof under different conditions can be simulated more accurately, thereby improving the accuracy of predicting potential collapse risks. This method considers the changing conditions of indicators over time, enabling dynamic monitoring of the cave roof's condition. This allows the early warning system to adjust its warning strategies promptly based on changes in the actual situation, ensuring the effectiveness of safety measures.

[0033] 2. By determining the critical value of the roof thickness based on the real-time stress of the overlying strata, an alarm can be issued before the roof of the karst cave approaches or reaches its ultimate bearing capacity, buying valuable time for preventive measures. Accurate and timely warnings can effectively prevent damage to buildings and infrastructure caused by sudden karst collapses, thereby reducing related repair costs and potential casualties. Attached Figure Description

[0034] The above and other features and advantages of the present invention will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0035] Figure 1 This is a flowchart illustrating an early warning method for karst collapse based on the dissolution rate of the rock on the roof of a cave, according to an exemplary embodiment.

[0036] Figure 2This is a schematic diagram of a karst collapse early warning system based on the dissolution rate of the rock on the roof of a cave, according to an exemplary embodiment.

[0037] Figure 3 This is a schematic diagram of the structure of an electronic device according to an exemplary embodiment. Detailed Implementation

[0038] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0039] The terms “a,” “one,” “the,” and “the” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended meaning of inclusion and that other elements / components / etc. may exist in addition to the listed elements / components / etc.

[0040] like Figure 1 The karst collapse early warning method based on the dissolution rate of the rock on the roof of a cave, as described in this embodiment of the invention, includes:

[0041] Step S101: Construct an underground karst cave simulation model, which includes the initial values ​​of each preset index and the index change conditions based on time series.

[0042] Specifically, based on geological data and geophysical exploration results, sonar testing instruments (in water-filled conditions) or 3D laser scanners (in non-water-filled conditions) are used to measure the karst caves. Suitable software for geotechnical engineering simulation is selected, such as FLAC3D, ABAQUS, and PLAXIS. The 3D geometry of the underground karst cave is then reproduced in the simulation software, forming a 3D simulation model. The 3D simulation model is then meshed to facilitate numerical simulation calculations. The mesh can be regular or irregular, depending on the specific shape and complexity of the karst cave.

[0043] In the simulation software, define the initial values ​​of various preset indicators, such as the initial thickness of the roof of the underground cave, the unit weight of the roof, the elastic modulus, Poisson's ratio, tensile strength, shear strength, etc., as well as the conditions for the change of indicators (i.e., the dissolution rate of the roof). Set appropriate boundary conditions, such as free surfaces and fixed boundaries, to simulate the actual geological environment and form an underground cave simulation model.

[0044] The initial values ​​of each preset index are obtained by drilling and sampling in the field, bringing the samples back to the laboratory, and analyzing the samples in the laboratory.

[0045] Step S102: Input the stress of the strata above the underground cave into the underground cave simulation model and run it.

[0046] Based on geological data or field-collected stratigraphic samples, as well as the physical and mechanical parameters of the strata, calculate the stress of each stratum above the underground cavern.

[0047] Define the boundary conditions of the formation in the simulation model. Typically, the bottom of the formation is used as the stress boundary condition, and the stresses calculated above are applied.

[0048] In the simulation software, the calculated stresses of each stratum above the underground cavern are input into the model. This step requires ensuring that the stress distribution is uniform and consistent with actual conditions.

[0049] Start the calculation process in the simulation software. The software will progressively calculate the state changes of the underground cavern roof at different points in time based on the input conditions and attributes. During the simulation, monitor the model's convergence and the calculation results in real time. If the model fails to converge or the results are abnormal, the simulation parameters need to be adjusted or the input data needs to be rechecked.

[0050] Step S103: Obtain the state of the underground cave roof after a preset time period.

[0051] The simulation results are analyzed to determine the stability and bearing capacity of the roof at different time points. If the roof reaches or approaches a critical state (i.e., collapse state) during the process, an early warning is triggered and the simulation is stopped.

[0052] Step S104: When the top of the underground cave is in a collapsed state, determine the real-time stress of the overlying strata of the underground cave simulation model.

[0053] Set collapse criteria: Define specific criteria for roof collapse, such as the maximum displacement of the roof exceeding a certain threshold, or damage occurring in the stress concentration zone.

[0054] During the simulation, the state changes of the cave roof are continuously monitored. Data output by the simulation software, such as displacement, stress, and strain, is used to determine whether the roof has reached a state of collapse.

[0055] When the simulation results show that the roof has reached a state of collapse, record the time point t. This time point is the critical moment when the roof transitions from a stable state to a collapsed state.

[0056] The real-time stress of the overlying strata at time t of collapse is extracted using simulation software. The real-time stress of the overlying strata includes the sum of the real-time stress of the roof of the underground cavern and the stress of the strata.

[0057] The real-time stress of the overlying strata is obtained by the following formula:

[0058] h = h0 - η t (1)

[0059]

[0060] Where h is the real-time thickness of the top plate, h0 is the initial thickness of the top plate, η is the dissolution rate, t is the elapsed time, γ is the unit weight of the top plate, P is the real-time stress of the overlying strata, and γ i Let h be the unit weight of the i-th stratum. i Let be the thickness of the i-th stratum.

[0061] Step S105: Based on the real-time stress of the overlying strata, determine the critical value of the top plate thickness of the underground karst cave simulation model.

[0062] By deriving the directions of formulas (1) and (2), the critical value of the top plate thickness is obtained.

[0063] In a preferred embodiment, the method for obtaining the top plate dissolution rate includes:

[0064] Obtain the thickness values ​​of the roof slabs of two underground karst caves at the same location at two different time points;

[0065] The erosion rate of the top plate is determined based on the two top plate thickness values ​​and the time interval between the two time points.

[0066] Specifically:

[0067] 1. Select monitoring location

[0068] Select one or more fixed monitoring points on the roof of the underground cavern. These monitoring points should be representative and able to reflect the erosion status of the entire roof.

[0069] The selected monitoring points are clearly marked to ensure that the same location can be accurately found at different times.

[0070] 2. Obtain the top plate thickness value

[0071] Initial measurement: At the first time point t1, the thickness h1 of the top plate at the selected monitoring point is measured using appropriate measuring tools (such as ultrasonic thickness gauge, laser rangefinder, etc.).

[0072] Record data: Record the measurement time t1 and the corresponding top plate thickness h1 in detail, and save the relevant data.

[0073] Subsequent measurements: At the second time point t2 (usually some time later), the thickness h2 of the top plate at the same monitoring point is measured again.

[0074] Record data: Record the measurement time t2 and the corresponding top plate thickness h2 in detail, and save the relevant data.

[0075] 3. Calculate the time interval

[0076] Calculate the time difference: Calculate the time interval Δt between two time points.

[0077] Δt=t2-t1

[0078] 4. Determine the roof dissolution rate

[0079] Calculate the thickness change: Calculate the thickness change Δh of the top plate between two time points:

[0080] Δh=h1-h2

[0081] Where h1 is the initial thickness and h2 is the thickness measured subsequently. If the top plate thins, Δh is a positive value; if the top plate thickens (e.g., due to deposition), Δh is a negative value.

[0082] Calculation of dissolution rate: Based on thickness variation and time interval, the dissolution rate η of the top plate is calculated:

[0083] η=Δh / Δt

[0084] The unit of η is usually meters per year (m / year) or millimeters per year (mm / year).

[0085] like Figure 2 The karst collapse early warning system based on the dissolution rate of the rock roof of a cave, as described in this embodiment of the invention, includes:

[0086] The construction module 201 is used to construct an underground karst cave simulation model, which includes the initial values ​​of each preset index and the index change conditions based on the time series.

[0087] The running module 202 is used to input the stress of the strata above the underground cave into the simulation model of the underground cave for operation;

[0088] The acquisition module 203 is used to obtain the state of the roof of the underground cave after a preset time period;

[0089] The determination module 204 is used to determine the real-time stress of the overlying strata of the underground karst cave simulation model when the top slab of the underground karst cave is in a state of collapse.

[0090] The determination module 204 is also used to determine the critical value of the top plate thickness of the underground karst cave simulation model based on the real-time stress of the overlying strata.

[0091] It should be noted that the above-mentioned construction module 201, running module 202, acquisition module 203 and determination module 204 correspond to steps S101 to S105 in the embodiment of the karst collapse early warning method based on the dissolution rate of the rock on the roof of the cave. The examples and application scenarios implemented by the above modules and corresponding steps are the same, but are not limited to the content disclosed in the above embodiments.

[0092] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages:

[0093] 1. By constructing a simulation model of underground karst caves and combining it with actual geological stress conditions, the changes in the cave roof under different conditions can be simulated more accurately, thereby improving the accuracy of predicting potential collapse risks. This method considers the changing conditions of indicators over time, enabling dynamic monitoring of the cave roof's condition. This allows the early warning system to adjust its warning strategies promptly based on changes in the actual situation, ensuring the effectiveness of safety measures.

[0094] 2. By determining the critical value of the roof thickness based on the real-time stress of the overlying strata, an alarm can be issued before the roof of the karst cave approaches or reaches its ultimate bearing capacity, buying valuable time for preventive measures. Accurate and timely warnings can effectively prevent damage to buildings and infrastructure caused by sudden karst collapses, thereby reducing related repair costs and potential casualties.

[0095] Embodiments of the present invention also provide a computer-readable storage medium storing a program or instructions that, when executed on a computer, cause the computer to perform the karst collapse early warning method based on the dissolution rate of the cave roof rock as described in the above embodiments.

[0096] like Figure 3 The present invention also provides an electronic device 300, comprising: a processor 301, wherein the processor 301 is coupled to a memory 302.

[0097] Processor 301 is used to read and execute computer programs stored in memory to implement the karst collapse early warning method based on the dissolution rate of the cave roof rock as described in the above method embodiments.

[0098] In this embodiment of the invention, the term "multiple" refers to two or more, unless otherwise explicitly defined. The terms "install," "connect," and "fix" should be interpreted broadly. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention based on the specific circumstances.

[0099] In the description of the embodiments of the present invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0100] In the description of this specification, the terms "an embodiment," "a preferred embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. For those skilled in the art, the embodiments of the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention.

Claims

1. A karst collapse early warning method based on the karst top plate rock dissolution rate, characterized in that, The method comprises the following steps: constructing an underground cave simulation model, wherein the underground cave simulation model comprises initial values of preset indexes and index change conditions based on time series, and the index change conditions comprise a roof erosion rate; inputting stratum stress above the underground cave into the underground cave simulation model for operation; obtaining a state of the roof of the underground cave after a preset time period; when the state of the roof of the underground cave is collapse, determining real-time stress of overlying strata of the underground cave simulation model; based on the real-time stress of the overlying strata, determining a critical value of the roof thickness of the underground cave simulation model; the real-time stress of the overlying strata is obtained by the following formula: wherein, h is the real-time thickness of the roof, h 0 is the initial thickness of the roof, η is the dissolution rate, t is the elapsed time, γ is the specific weight of the roof, P is the real-time stress of the overburden, γ i is the specific weight of the first i layer of the formation, h i is the thickness of the first i layer of the formation. 2.The karst collapse early warning method based on the karst top rock dissolution rate according to claim 1, characterized in that, the real-time stress of the overlying strata is the sum of the real-time stress of the roof of the underground cave and the stratum stress. 3.The karst collapse early warning method based on the karst top rock dissolution rate according to claim 1, characterized in that, the initial values of the preset indexes comprise initial thickness of the roof of the underground cave, specific gravity of the roof, elastic modulus, Poisson's ratio, tensile strength and shear strength. 4.The karst collapse early warning method based on the karst top rock dissolution rate according to claim 1, characterized in that, The method for obtaining the roof erosion rate comprises the following steps: obtaining two roof thickness values of the underground cave at the same position corresponding to two time points; based on the two roof thickness values and the interval time of the two time points, determining the roof erosion rate. 5.The karst collapse early warning method based on the dissolution rate of cave roof rock according to claim 1, characterized in that, The method further comprises the following steps: when the state of the underground cave is collapse, triggering a warning.

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