Karst collapse early warning method based on karst cave roof rock corrosion rate

Abstract

The invention provides a karst collapse early warning method based on a karst cave roof rock corrosion rate, and belongs to the technical field of geological disaster monitoring and early warning. The karst collapse early warning method based on the karst cave roof rock corrosion rate comprises the steps that an underground karst cave simulation model is constructed, and the underground karst cave simulation model comprises initial values of all preset indexes and index change conditions based on a time sequence; the stratum stress above the underground karst cave is input into the underground karst cave simulation model for operation; obtaining an underground karst cave roof state after a preset time period; when the state of the underground karst cave roof is collapse, the real-time stress of the overlying stratum of the underground karst cave simulation model is determined; and determining a roof thickness critical value of the underground karst cave simulation model based on the real-time stress of the overlying stratum. According to the method, the change conditions of the karst cave roof under different conditions are accurately simulated, so that the prediction accuracy of the potential collapse risk is improved. According to the method, index change conditions on a time sequence are considered, and dynamic monitoring of the state of the karst cave roof can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of geological disaster monitoring and early warning, and in particular to a karst collapse early warning method based on the dissolution rate of cave roof rocks. Background Art

[0002] Karst collapse is a global geological disaster that is particularly common in countries and regions with widespread karst landforms. China, a country where karst areas account for about one-third of its land area, is particularly prone to karst collapse. This type of collapse is usually caused by the roof of underground karst caves being unable to support the overlying load, resulting in surface subsidence or the formation of collapse pits, posing a serious threat to building safety, infrastructure integrity and people's lives.

[0003] Karst collapse disasters are characterized by suddenness and concealment, which makes it difficult to achieve the purpose of early warning through surface monitoring before the disaster occurs. Traditional surface movement and deformation monitoring methods have limited early warning effects on such disasters, because the surface often does not show obvious displacement before collapse. In addition, although geophysical exploration methods can detect the existence and approximate location of underground caves, this method is costly, and the detection accuracy is affected by many factors. At the same time, it cannot provide continuous monitoring data.

[0004] The cave roof is a key structure that supports the overlying strata, and its thickness change is directly related to whether the karst will collapse. With the action of groundwater, the rock of the cave roof is constantly dissolved, resulting in a gradual decrease in the thickness of the roof, a significant reduction in strength and stability, and thus a decrease in its bearing capacity. Once the bearing capacity of the cave roof is insufficient to support the load of the overlying strata, collapse will occur. Therefore, how to effectively monitor the thickness changes of the cave roof and issue a collapse warning based on this has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a real-time monitoring of the thickness change and stress change of the roof rock of the underground cave, so as to predict and warn the possible karst collapse time and the thickness of the roof rock of the cave at the time of collapse.

[0006] In a first aspect, a karst collapse early warning method based on the dissolution rate of cave roof rock is provided, comprising:

[0007] Constructing an underground cave simulation model, wherein the underground cave simulation model includes initial values ​​of various preset indicators and indicator change conditions based on a time series; the indicator change conditions include a roof dissolution rate;

[0008] Inputting the stratum stress above the underground cave into the underground cave simulation model for operation;

[0009] Obtain the state of the underground cave roof after a preset time period;

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

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

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

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

[0014] h=h0-η t (1)

[0015]

[0016] Among them, h is the real-time thickness of the roof, h0 is the initial thickness of the roof, η is the dissolution rate, t is the elapsed time, γ is the weight of the roof, P is the real-time stress of the overlying stratum, γ i is the stratum weight of the i-th layer, h i is the thickness of the i-th layer.

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

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

[0019] Obtain two roof thickness values ​​of an underground cave at the same location corresponding to two time points;

[0020] The roof dissolution rate is determined based on the two roof thickness values ​​and the interval between the two time points.

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

[0022] In a second aspect, a karst collapse early warning system based on the dissolution rate of cave roof rock is provided, comprising:

[0023] A construction module, used to construct an underground cave simulation model, wherein the underground cave simulation model includes initial values ​​of various preset indicators and indicator change conditions based on time series;

[0024] An operation module, used for inputting the stratum stress above the underground cave into the underground cave simulation model for operation;

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

[0026] A determination module, used for determining the real-time stress of the overlying strata of the underground cave simulation model when the roof of the underground 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 cave simulation model based on the real-time stress of the overlying stratum.

[0028] According to a third aspect, a computer-readable storage medium is provided, which stores a program or instruction. When the program or instruction is executed on a computer, the computer executes the karst collapse early warning method based on the dissolution rate of the cave roof rock as described in the above technical solution.

[0029] In a fourth aspect, an electronic device is provided, comprising: a processor, the processor being 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 an underground cave simulation model and combining it with the actual stratum 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 takes into account the indicator change conditions in the time series and can realize dynamic monitoring of the state of the cave roof. This allows the early warning system to adjust the early warning strategy in a timely manner according to changes in the actual situation to ensure the effectiveness of safety measures.

[0033] 2. Determine the critical value of the roof thickness based on the real-time stress of the overlying strata, and issue an alarm before the cave roof approaches or reaches its ultimate bearing capacity, buying valuable time for taking preventive measures. Accurate and timely early warning can effectively avoid damage to buildings and infrastructure caused by sudden karst collapse, thereby reducing related repair costs and possible casualties. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

[0035] Figure 1 is a flow chart showing a karst collapse early warning method based on the dissolution rate of cave roof rock according to an exemplary embodiment;

[0036] Figure 2is a structural schematic diagram of a karst collapse early warning system based on the dissolution rate of cave roof rocks according to an exemplary embodiment;

[0037] Figure 3 is a schematic structural diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0039] The terms "a", "an", "the", and "said" are used to indicate the presence of one or more elements / components / etc.; the terms "comprising" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may be present 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 cave roof rock in the embodiment of the present invention includes:

[0041] Step S101: constructing an underground cave simulation model, wherein the underground cave simulation model includes initial values ​​of various preset indicators and indicator change conditions based on time series.

[0042] Specifically, based on geological data and geophysical exploration results, use a sonar tester (water-filled state) or a three-dimensional laser scanner (non-water-filled state) to measure the cave. Select software suitable for geotechnical engineering simulation, such as FLAC3D, ABAQUS, PLAXIS, etc. Invert the three-dimensional geometric shape of the underground cave in the simulation software to form a simulated three-dimensional model. Divide the simulated three-dimensional model into a grid for numerical simulation calculations. The grid can be regular or irregular, depending on the specific shape and complexity of the cave.

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

[0044] The initial value of each preset indicator is 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: inputting the stratum stress above the underground cave into the underground cave simulation model for operation.

[0046] Based on geological data or stratum samples collected on site, as well as the physical and mechanical parameters of the stratum, the stress and of each stratum above the underground cave are calculated.

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

[0048] In the simulation software, the calculated stress and pressure of each layer above the underground cave are input into the model. This step needs to ensure that the stress distribution is uniform and consistent with the actual situation.

[0049] Start the calculation process in the simulation software. The simulation software will gradually calculate the state changes of the underground cave roof at different time points based on the various input conditions and attributes. During the simulation process, monitor the convergence of the model and the calculation results in real time. If the model does not converge or the results are abnormal, you need to adjust the simulation parameters or recheck the input data.

[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 load-bearing capacity of the roof at different time points. If the roof reaches or approaches a critical state (i.e., collapse) during this process, an early warning is triggered and the simulation is stopped.

[0052] Step S104: when the roof of the underground cave is in a collapsed state, determining 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, damage in the stress concentration area, etc.

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

[0055] When the simulation results show that the roof reaches the collapsed state, record the time point t at this time. This time point is the critical moment when the roof changes from a stable state to a collapsed state.

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

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

[0058] h=h0-η t (1)

[0059]

[0060] Among them, h is the real-time thickness of the roof, h0 is the initial thickness of the roof, η is the dissolution rate, t is the elapsed time, γ is the weight of the roof, P is the real-time stress of the overlying stratum, γ i is the stratum weight of the i-th layer, h i is the thickness of the i-th layer.

[0061] Step S105: Determine a critical value of the top plate thickness of the underground cave simulation model based on the real-time stress of the overlying strata.

[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 roof dissolution rate includes:

[0064] Obtain two roof thickness values ​​of an underground cave at the same location corresponding to two time points;

[0065] The roof dissolution rate is determined based on the two roof thickness values ​​and the interval between the two time points.

[0066] Specific:

[0067] 1. Select monitoring location

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

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

[0070] 2. Get the top plate thickness value

[0071] Initial measurement: At the first time point t1, use an appropriate measuring tool (such as ultrasonic thickness gauge, laser rangefinder, etc.) to measure the roof thickness h1 at the selected monitoring point.

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

[0073] Subsequent measurement: At the second time point t2 (usually after a period of time), the roof thickness h2 of the same monitoring point is measured again.

[0074] Record data: Also record the measured 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 interval time Δt between two time points:

[0077] Δt=t2-t1

[0078] 4. Determine the roof dissolution rate

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

[0080] Δh=h1-h2

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

[0082] Calculate the dissolution rate: Based on the thickness change and time interval, calculate the dissolution rate η of the roof:

[0083] η=Δh / Δt

[0084] The unit of η is usually meter / year (m / year) or millimeter / year (mm / year).

[0085] like Figure 2 The karst collapse early warning system based on the dissolution rate of cave roof rock in the embodiment of the present invention comprises:

[0086] A construction module 201 is used to construct an underground cave simulation model, wherein the underground cave simulation model includes initial values ​​of various preset indicators and indicator change conditions based on time series;

[0087] An operation module 202 is used to input the stratum stress above the underground cave into the underground cave simulation model for operation;

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

[0089] A determination module 204 is used to determine the real-time stress of the overlying strata of the underground cave simulation model when the roof of the underground cave is in a collapsed state;

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

[0091] It should be noted here that the above-mentioned construction module 201, operation 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 cave roof rock. The examples and application scenarios implemented by the above-mentioned modules and corresponding steps are the same, but are not limited to the contents disclosed in the above-mentioned embodiments.

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

[0093] 1. By constructing an underground cave simulation model and combining it with the actual stratum 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 takes into account the indicator change conditions in the time series and can realize dynamic monitoring of the state of the cave roof. This allows the early warning system to adjust the early warning strategy in a timely manner according to changes in the actual situation to ensure the effectiveness of safety measures.

[0094] 2. Determine the critical value of the roof thickness based on the real-time stress of the overlying strata, and issue an alarm before the cave roof approaches or reaches its ultimate bearing capacity, buying valuable time for taking preventive measures. Accurate and timely early warning can effectively avoid damage to buildings and infrastructure caused by sudden karst collapse, thereby reducing related repair costs and possible casualties.

[0095] An embodiment of the present invention also provides a computer-readable storage medium storing a program or instruction. When the program or instruction is executed on a computer, the computer executes the karst collapse early warning method based on the dissolution rate of the cave roof rock as described in the above embodiment.

[0096] like Figure 3 The embodiment of the present invention further provides an electronic device 300, including: a processor 301, the processor 301 is coupled to a memory 302,

[0097] The processor 301 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 method embodiment.

[0098] In the embodiments of the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installation", "connection", "fixation" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0099] In the description of the embodiments of the present invention, it needs to be understood that the directions or positional relationships indicated by the terms "upper" and "lower" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the embodiments of the present invention.

[0100] In the description of this specification, the description of the terms "one embodiment", "a preferred embodiment", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0101] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A karst collapse early warning method based on the dissolution rate of cave roof rock, characterized in that: include: Constructing an underground cave simulation model, wherein the underground cave simulation model includes initial values ​​of various preset indicators and indicator change conditions based on time series, wherein the indicator change conditions include roof dissolution rate; Inputting the stratum stress above the underground cave into the underground cave simulation model for operation; Obtain the state of the underground cave roof after a preset time period; When the roof of the underground cave is in a collapsed state, determining the real-time stress of the overlying strata of the underground cave simulation model; Based on the real-time stress of the overlying strata, a critical value of the roof thickness of the underground cave simulation model is determined.

2. The karst collapse early warning method based on the dissolution rate of cave roof rock according to claim 1 is characterized in that: The real-time stress of the overlying stratum 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 dissolution rate of cave roof rock according to claim 1 or 2, characterized in that: The real-time stress of the overlying strata is obtained by the following formula: h=h0-ηt#(1) Where h is the real-time thickness of the roof, h0 is the initial thickness of the roof, η is the dissolution rate, t is the elapsed time, γ is the weight of the roof, P is the real-time stress of the overlying stratum, γi is the weight of the i-th stratum, and h i is the thickness of the i-th layer.

4. The karst collapse early warning method based on the dissolution rate of cave roof rock according to claim 1 is characterized in that: The initial values ​​of the preset indicators include the initial thickness of the cave roof, the weight of the roof, the elastic modulus, the Poisson's ratio, the tensile strength, and the shear strength.

5. The karst collapse early warning method based on the dissolution rate of cave roof rock according to claim 1 is characterized in that: The method for obtaining the roof dissolution rate includes: Obtain two roof thickness values ​​of an underground cave at the same location corresponding to two time points; The roof dissolution rate is determined based on the two roof thickness values ​​and the interval between the two time points.

6. The karst collapse early warning method based on the dissolution rate of cave roof rock according to claim 1 is characterized in that: Also includes: When the cave is in a collapsed state, an early warning is triggered.

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