Plain area sudden land subsidence process simulation box and experiment method

Abstract

The invention relates to the technical field of land subsidence simulation and monitoring, and discloses a plain area sudden land subsidence process simulation box which comprises a plain area land subsidence process simulation layer used for simulating the land subsidence process of a water-bearing layer and a water-resisting layer; the deep stratum negative pressure simulation layer is used for simulating the water and sand leakage process under the karst cavity negative pressure condition; the experimental method of the plain area sudden land subsidence process simulation box comprises the following steps that the plain area land subsidence simulation box is constructed, and the simulation box comprises a plain area land subsidence process simulation layer and a deep stratum negative pressure simulation layer; a water head control system, a precipitation control system, a loading system, a deep negative pressure simulation system and a precipitation circulation system are arranged in the simulation box. Through multi-system coupling simulation and multi-parameter dynamic monitoring, accurate simulation of the water head pressure, the load effect and the water and sand loss process is achieved, the stratum instability mechanism is revealed, and high-precision risk early warning is provided.

Description

Technical Field

[0001] The invention relates to the technical field of ground subsidence simulation and monitoring, and in particular to a simulation box and an experimental method for sudden ground subsidence in a plain area. Background Art

[0002] Sudden ground subsidence in plain areas is a common and serious problem in the geological environment. It is mainly manifested as sudden local or regional sinking of the surface, which leads to damage or even failure of infrastructure such as buildings and roads. The factors causing ground subsidence are complex, including abnormal drop in groundwater level, increase in building load and water and sand loss caused by karst cavities. In this context, it is very important to study the formation mechanism, evolution law and risk warning method of sudden ground subsidence in plain areas. Constructing a simulation box and experimental method for sudden ground subsidence process in plain areas can provide experimental data and theoretical support for the prevention and control of ground subsidence.

[0003] Existing ground subsidence simulation devices in plain areas mainly focus on simulating the compression deformation of aquifers, and reflect the ground subsidence caused by the drop in groundwater levels by adjusting water level changes. Some devices have realized static monitoring of aquifer deformation under load, and captured the displacement and stress distribution of the formation through a certain sensor system. These technologies can simulate the relationship between groundwater level and formation deformation, reveal the impact of aquifer compression deformation on ground subsidence, and have certain visualization effects and data collection capabilities, providing basic support for the study of ground subsidence mechanisms.

[0004] However, existing technologies still have shortcomings in simulating sudden ground subsidence in plain areas. First, there is a lack of coupled simulation of factors such as head pressure, load and water and sand loss, and it is impossible to fully reflect the formation subsidence process under the coupling of multiple factors. Secondly, it fails to simulate the rapid loss of water and sand under the negative pressure conditions of deep karst cavities, and cannot reveal the key triggering mechanism of aquifer instability. In addition, the data monitoring and early warning functions of the existing system are relatively single, and lack the ability to dynamically monitor multiple parameters and provide risk early warning. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a simulation box and experimental method for sudden land subsidence process in plain areas, which solves the problem that the prior art cannot realize the coupled simulation of multiple factors such as head pressure, load effect and water and sand loss.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a simulation box for sudden land subsidence in plain areas, the simulation box comprising:

[0007] The simulation layer of land subsidence process in plain area is used to simulate the land subsidence process of aquifer and aquiclude;

[0008] The deep formation negative pressure simulation layer is used to simulate the water and sand loss process under the negative pressure condition of the karst cavity;

[0009] Head control system, which controls the head pressure of the aquifer by adjusting the water level in the water tank;

[0010] Precipitation control system, used to simulate precipitation recharge processes of different intensities;

[0011] Load system, which simulates building and road loads through point loads and surface loads;

[0012] Sedimentation circulation system to achieve water-sand filtration and water resource circulation;

[0013] The sensor system is used to collect data such as water head pressure, stress, displacement, temperature, etc., and cooperates with high-frequency camera equipment to record the entire experimental process.

[0014] Preferably, constructing a land subsidence simulation box in a plain area includes:

[0015] The simulation box has a size of 2m×2m×3m, and the main frame of the simulation box is a steel structure;

[0016] Organic glass plates are embedded around the simulation box to facilitate observation of internal structural changes;

[0017] Three layers of aquifers are arranged in layers inside the simulation box, and the aquifers are filled with sand with different particle sizes;

[0018] An impermeable layer is arranged between the aquifers. The impermeable layer is filled with low-permeability clay material and has a thickness of 0.15 to 0.25 m.

[0019] Preferably, the water head control system comprises:

[0020] Three groups of water tanks are set on both sides of the simulation box, and the size of the water tanks is 2m×2m×0.1m 3 ;

[0021] The water tank is connected to the three aquifers through free pipes, and the water level in the water tank is controlled by a float valve to control the head pressure;

[0022] A water head pressure sensor is buried inside the aquifer to monitor the water head height and pressure changes in real time.

[0023] Preferably, the precipitation control system comprises:

[0024] A spray device is evenly arranged on the top of the simulation box, wherein the spray device includes a plurality of spray heads with adjustable flow rates;

[0025] The water source is supplied by a water pump, and the nozzle realizes precipitation replenishment of different intensities;

[0026] The precipitation process is carried out in stages according to the experimental requirements to simulate different water level recharge conditions.

[0027] Preferably, the load system comprises:

[0028] Arranging point loads and surface loads on the top of the simulation box;

[0029] The point load simulates the effect of a single-story building through a concentrated load of 0.1 to 1.2 kg;

[0030] The surface load is laid out by stacking 20×10×1cm steel plates to simulate high-rise building and road loads;

[0031] Gradual loading: initially load 50% of the design load, and then gradually load in 10% increments until the ground settlement changes.

[0032] Preferably, the deep negative pressure simulation system comprises:

[0033] A deep negative pressure simulation layer is arranged at the bottom of the simulation box, and a negative pressure environment is formed by a vacuum pump;

[0034] A leakage hole with a diameter of 1 cm to 3 cm is set on the vertical organic glass pipe;

[0035] By opening the leakage hole and the negative pressure simulation valve, the rapid leakage of water and sand from the aquifer to the deep karst cavity is triggered;

[0036] Adjust the negative pressure value of the vacuum pump to form different negative pressure conditions of -10 to -30 kPa.

[0037] Preferably, the precipitation circulation system comprises:

[0038] A sedimentation tank and a water pump are arranged outside the simulation box;

[0039] The sedimentation tank is used to filter the discharged water-sand mixture to complete solid-liquid separation;

[0040] The filtered water is returned to the water head control system through a water pump to achieve the recycling of water resources.

[0041] Preferably, the sensor arrangement includes:

[0042] A water head pressure sensor, a stress sensor, a displacement sensor and a temperature sensor are arranged inside the aquifer;

[0043] The water head pressure sensor is used to monitor the water level change of the aquifer;

[0044] The stress sensor is used to monitor the internal stress distribution of the soil;

[0045] The displacement sensor is used to monitor ground settlement and deformation rate;

[0046] High-frequency video equipment is used to record the entire experiment process and capture the dynamic changes in the stratum structure.

[0047] Preferably, the data analysis includes:

[0048] Collect experimental data such as water head pressure, soil stress, displacement, flow and temperature;

[0049] Analyze the correlation between the change of aquifer head pressure and the amount of sedimentation;

[0050] Determine soil deformation and stress mutation points under load and negative pressure;

[0051] The critical water level, stress threshold and maximum settlement rate are obtained to form a risk warning plan.

[0052] The present invention also provides an experimental method for a simulation box for sudden land subsidence process in a plain area, comprising the following steps:

[0053] Constructing a plain area ground subsidence simulation box, the simulation box comprising a plain area ground subsidence process simulation layer and a deep stratum negative pressure simulation layer;

[0054] A water head control system, a precipitation control system, a load system, a deep negative pressure simulation system and a sedimentation circulation system are arranged inside the simulation box;

[0055] The water head pressure of the aquifer is adjusted by the water head control system to simulate the water level drop process of the aquifer;

[0056] Apply point loads and surface loads through the load system to simulate the effects of building and road loads;

[0057] Start the deep negative pressure simulation system to simulate the water and sand loss process under the negative pressure condition of the karst cavity;

[0058] Water sand filtration is performed through a sedimentation circulation system to ensure water resource circulation;

[0059] Sensors are placed inside the aquifer to collect data such as head pressure, soil stress, displacement and temperature in real time, and perform data analysis.

[0060] The present invention provides a simulation box and experimental method for sudden land subsidence in plain areas, which has the following beneficial effects:

[0061] 1. The present invention realizes accurate simulation of dynamic changes in water levels, building loads and ground subsidence processes by arranging aquifers and impermeable layers in layers, combining water head control systems, precipitation control systems and load systems. The device can quantify the coupling effects of hydraulic action and load pressure on stratum deformation, capture key nodes and evolution laws of subsidence, and provide accurate data support for the study of ground subsidence mechanisms under complex working conditions.

[0062] 2. The present invention realistically reproduces the phenomenon of rapid water and sand loss under negative pressure conditions in karst cavities through the deep negative pressure simulation system and leakage hole settings. Combined with the sensor system to achieve dynamic monitoring, the system can identify the formation instability mechanism and stress mutation points caused by water and sand loss, providing a scientific basis for studying the triggering mechanism of sudden ground subsidence.

[0063] 3. The present invention integrates multi-parameter sensors such as head pressure, stress, displacement, and flow, and combines high-frequency camera equipment and data analysis systems to achieve real-time monitoring and data collection of the entire experimental process. Through the construction of key data threshold analysis and risk warning models, it can accurately identify ground subsidence risks, provide warning signals, and effectively support the risk prevention and control of ground subsidence disasters. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 is a plan view of the present invention;

[0065] Figure 2 A top view of the top precipitation system of the present invention;

[0066] Figure 3 A top view of the bottom negative pressure simulation layer of the present invention;

[0067] Figure 4 It is a side view of the large sandbox of the present invention;

[0068] Figure 5 It is a top view of the point and surface load distribution of the present invention;

[0069] Figure 6 The present invention is a flow chart of the method. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] Please refer to the attached Figure 1 -Attached Figure 5The embodiment of the present invention provides a simulation box for sudden land subsidence in a plain area, and the simulation box includes:

[0072] The simulation layer of ground subsidence in plain areas is used to simulate the ground subsidence process of aquifers and aquicludes. Through the reconstruction of the real geological structure, it can accurately reflect the deformation and subsidence process of aquifers under different hydrogeological conditions, and provide accurate data for the study of ground subsidence mechanism;

[0073] The deep formation negative pressure simulation layer is used to simulate the water and sand loss process under the negative pressure condition of the karst cavity. The deep formation negative pressure simulation layer can reproduce the water and sand loss process under the karst cavity condition and reveal the triggering mechanism of water and sand loss on the sudden ground subsidence;

[0074] The water head control system controls the water head pressure of the aquifer by adjusting the water level in the water tank. By adjusting the water level in the water tank, the water head pressure of different aquifers can be accurately controlled to simulate the dynamic changes of the groundwater level, thereby achieving precise regulation of the water head pressure of the aquifer and providing reliable support for the simulation and analysis of ground subsidence under different water level drop conditions;

[0075] The precipitation control system is used to simulate precipitation recharge processes of different intensities. The precipitation control system achieves a high degree of restoration of natural precipitation conditions, providing an experimental basis for the response study of aquifers under groundwater recharge conditions;

[0076] The load system simulates the building and road loads through point loads and surface loads. The load intensity is gradually increased through graded loading to simulate the pressure of different building structures on the aquifer.

[0077] The sedimentation circulation system realizes water-sand filtration and water resource circulation, filters the water-sand mixture, ensures the continuous circulation of water resources inside the experimental system, thus avoiding the waste of water resources, and maintains the continuous operation of the water head control system, providing guarantee for long-term experiments;

[0078] The sensor system is used to collect data such as head pressure, stress, displacement, temperature, etc., and cooperates with high-frequency video equipment to record the entire experimental process. The sensor system can realize multi-factor synchronous monitoring and data collection, providing comprehensive data support for the analysis of the entire process of sudden ground subsidence and revealing its mechanism.

[0079] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, constructing a land subsidence simulation box in a plain area includes:

[0080] The simulation box has a size of 2m×2m×3m. The main frame of the simulation box is a steel structure. The steel structure frame design of this size ensures the structural strength and stability of the simulation box. It can withstand complex working conditions such as multi-layer load application, seepage pressure and deep negative pressure, thereby ensuring the stability of the simulation box under high load, negative pressure and multiple factors, extending the service life of the experimental device, and providing a stable experimental environment for accurate simulation of ground subsidence.

[0081] Organic glass plates are embedded around the simulation box to facilitate observation of internal structural changes. The high transparency of the organic glass plates enables intuitive observation of the dynamic changes of the aquifer, aquiclude and stratum settlement inside the simulation box during the experiment.

[0082] Three layers of aquifers are set up in layers inside the simulation box. The aquifers are filled with sands of different particle sizes. Sands of different particle sizes have different permeability properties, forming aquifer structures with different seepage velocities and pressure conduction, which truly simulates the actual conditions of multi-layer aquifers in nature. Through the reasonable distribution and layered construction of sands of different particle sizes, the simulation box can reproduce the hydraulic characteristics and deformation characteristics of multi-layer aquifers, meeting the simulation requirements of water-sand seepage and ground subsidence processes under different experimental conditions.

[0083] An aquiclude is set between the aquifers. The aquiclude is filled with low-permeability clay material with a thickness of 0.15 to 0.25 m. The aquiclude has extremely low permeability and can effectively block the water infiltration between different aquifers, forming a hydraulic isolation effect. It truly reflects the distribution characteristics of aquifers and aquicludes in natural geological conditions. Through the setting of high-quality aquicludes, hydraulic interference between different aquifers is prevented, ensuring the independence of head pressure changes in the experiment, and providing a more accurate ground subsidence simulation effect.

[0084] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, the water head control system comprises:

[0085] Three sets of water tanks are set on both sides of the simulation box, and the size of the water tank is 2m×2m×0.1m 3 , through the independent setting of three groups of water tanks, the head pressure of the three aquifers can be adjusted separately, simulating the water level conditions of different aquifers to ensure the accuracy and independence of head control;

[0086] The water tank is connected to the three-layer aquifer through a free pipe. The water level in the water tank is controlled by a float valve to control the head pressure. The combination of the free pipe and the float valve realizes the precise regulation of the head pressure, which can continuously and stably simulate the dynamic process of the water level drop or recharge of the aquifer, and provide highly controllable experimental conditions. The combination of the free pipe and the float valve realizes the precise regulation of the head pressure, which can continuously and stably simulate the dynamic process of the water level drop or recharge of the aquifer, and provide highly controllable experimental conditions.

[0087] A head pressure sensor is buried inside the aquifer to monitor the head height and pressure changes in real time. The measurement principle of the head pressure sensor is based on the water pressure conduction effect. By sensing the hydrostatic pressure of the water body inside the aquifer, the real-time values ​​of the head height and pressure are calculated to form accurate monitoring data.

[0088] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, the precipitation control system comprises:

[0089] The spray device is evenly arranged on the top of the simulation box. The spray device includes multiple nozzles with adjustable flow. The spray device provides water through a pressure pump. The nozzles spray the water evenly onto the inner surface of the simulation box to form a uniform water curtain simulating natural precipitation. The adjustable nozzle flow and spray angle can accurately control the precipitation of different intensities and distributions.

[0090] The water source is supplied by the water pump, and the sprinkler head realizes precipitation replenishment of different intensities. The water is pressurized by the water pump, and the pressure and flow are accurately controlled by the regulating valve to ensure the stable operation of the sprinkler. The water pump system is combined with the circulating water source to form a closed water resource utilization system to ensure the continuity and controllability of the water supply, thereby ensuring the sustainability and accuracy of the simulated precipitation process. At the same time, the water circulation system improves resource utilization and reduces experimental costs;

[0091] The precipitation process is carried out in stages according to the experimental needs to simulate different water level recharge conditions. The staged precipitation control achieves a high degree of restoration of the natural precipitation recharge process and can simulate the impact of precipitation of different intensities on the dynamic changes of groundwater levels, providing scientific data support for studying the response mechanism under water recharge conditions in ground subsidence.

[0092] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, the load system comprises:

[0093] Point loads and surface loads are placed on the top of the simulation box. By applying different forms of loads (point and surface), local and overall structural loads on the urban ground are simulated, and the compression and deformation effects of these loads on the aquifer and stratum structure are analyzed. The layout of the load system can truly simulate the pressure effects of various engineering structures such as single-story buildings, high-rise buildings and road loads, providing real and controllable experimental conditions for analyzing the triggering mechanism of load changes on ground subsidence;

[0094] Point load simulates the effect of a single-story building through a concentrated load of 0.1-0.2 kg. The concentrated load acts on a specific point position, so that the load pressure is transmitted to the surface of the aquifer, resulting in local compression, thereby causing local deformation and settlement of the aquifer soil. The simulation method of point load can accurately restore the impact of the local load of a single-story building on the aquifer, revealing the destructive mechanism of local pressure concentration on the stability of the soil structure;

[0095] The surface load is laid out by stacking 20×10×1cm steel plates to simulate the loads of high-rise buildings and roads. The surface load simulates the loads of high-rise buildings, roads and other large-area structures in a uniformly distributed form. Its mechanical conduction compresses the surface of the aquifer and causes overall compression settlement. The layout of the surface load can truly simulate the uniform distribution characteristics of urban roads and high-rise building loads, and analyze the overall compression effect and deformation law of distributed loads on ground settlement.

[0096] Graded loading: initially load 50% of the design load, then gradually load in 10% increments until the ground settlement changes. Graded loading can simulate the dynamic effect of building loads in the process of gradual increase. By gradually increasing the load intensity, it can induce compression deformation of the aquifer and ground settlement, and capture the mutation phenomenon caused by the critical load. The graded loading method can accurately control the intensity and timing of the load, truly simulate the gradual loading process of buildings and road loads, help identify the critical relationship between load pressure and ground settlement, and provide a scientific basis for the early warning threshold of load-induced settlement.

[0097] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, the deep negative pressure simulation system comprises:

[0098] A deep negative pressure simulation layer is set at the bottom of the simulation box, and a negative pressure environment is formed by a vacuum pump. The deep negative pressure simulation layer forms negative pressure conditions through a vacuum pump to simulate the low pressure environment inside the karst cavity, causing the water and sand in the upper aquifer to quickly leak into the cavity under the action of pressure difference;

[0099] Leakage holes with a diameter of 1 to 3 cm are set on the vertical plexiglass pipe. The vertical plexiglass pipe and the leakage hole setting provide a visual leakage channel, which can simulate the water and sand loss process of different scales and forms, and provide accurate data for analyzing the instability of the aquifer caused by water and sand leakage;

[0100] By opening the leakage hole and the negative pressure simulation valve, the rapid leakage of water and sand from the aquifer to the deep karst cavity is triggered. The negative pressure simulation layer reduces the internal pressure through the vacuum pump, forming a significant pressure difference, which prompts the water and sand particles in the aquifer to migrate to the low-pressure area, simulating the rapid water and sand leakage process triggered by the karst cavity. Through negative pressure regulation and pressure difference formation, the rapid leakage of water and sand caused by negative pressure in the karst cavity can be truly simulated, revealing the response mechanism between water and sand leakage and formation instability;

[0101] The negative pressure value of the vacuum pump is adjusted to form different negative pressure conditions of -10 to -30 kPa. As the negative pressure value increases, the pressure difference further increases, the migration rate of water and sand particles inside the aquifer is accelerated, and the loss process gradually intensifies until the aquifer structure becomes unstable, triggering formation subsidence. By gradually adjusting the negative pressure value and the opening state of the leakage hole, the water and sand loss process under different pressure differences and leakage channel conditions can be accurately simulated, providing systematic experimental support for studying the triggering mechanism and instability law of sudden ground subsidence.

[0102] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, the precipitation circulation system comprises:

[0103] Set up a sedimentation tank and a water pump outside the simulation box. The sedimentation tank separates the discharged water-sand mixture into solid and liquid through multi-stage filtration and gravity sedimentation. The sand is deposited at the bottom of the tank, and the filtered water enters the next circulation link.

[0104] The sedimentation tank is used to filter the discharged water-sand mixture and complete the solid-liquid separation. The water pump transports the filtered clean water in the sedimentation tank to the water head control system through mechanical action, forming an efficient recycling of water resources and meeting the needs of aquifer recharge in the experiment, thereby ensuring the continuous water supply of the water head control system during the experiment, improving the sustainability and stability of the experimental system and reducing water resource waste;

[0105] The filtered water is returned to the water head control system through a pump to achieve the recycling of water resources. The water and sand circulation process can effectively recover the discharged water and sand through solid-liquid separation and water source return technology to form a closed circulation system to meet the needs of water head replenishment and continuous precipitation in the experiment, thereby ensuring the stability and continuity of water resource supply during the experiment, while reducing water resource waste during the experiment and improving the sustainability of the system.

[0106] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, the sensor arrangement includes:

[0107] A water head pressure sensor, a stress sensor, a displacement sensor and a temperature sensor are arranged inside the aquifer;

[0108] The water head pressure sensor is used to monitor the water level change of the aquifer. The water head pressure sensor uses the principle of water pressure conduction to measure the internal water pressure value of the aquifer, convert it into the corresponding water level height, and dynamically reflect the change of the water head pressure of the aquifer;

[0109] Stress sensors are used to monitor the stress distribution inside the soil. By measuring the pressure changes inside the soil, stress sensors reflect the stress distribution of the aquifer caused by factors such as building loads and head pressure changes, and reveal the conduction mechanism of stratum stress. Stress sensors can accurately capture the stress change laws inside the aquifer and aquiclude, and provide reliable data support for analyzing the stress state and instability mechanism of the soil under different load conditions.

[0110] Displacement sensors are used to monitor ground settlement and deformation rate. Displacement sensors dynamically reflect the rate and degree of ground settlement by monitoring the deformation of the ground surface and inside. They analyze the evolution of ground settlement by combining stress and water pressure data. Displacement sensors can monitor ground settlement and deformation rate in real time, provide accurate data support for revealing the laws of ground settlement caused by different factors, and help evaluate settlement risks and early warning mechanisms.

[0111] High-frequency video equipment is used to record the entire process of the experiment and capture the dynamic changes of the stratum structure. Through continuous high-speed shooting, the high-frequency video equipment captures the dynamic images of water and sand loss in the aquifer, crack expansion, soil deformation and ground subsidence, thereby realizing a visual record of the experimental process, thus being able to clearly show the dynamic evolution process of the stratum structure and provide important image data for the mechanism research and experimental verification of ground subsidence.

[0112] Please refer to the attached Figure 1 -Attached Figure 5 In a preferred embodiment of the present invention, data analysis includes:

[0113] Collect experimental data such as water head pressure, soil stress, displacement, flow and temperature. Through multi-sensor linkage and high-precision data acquisition system, fully capture the dynamic changes of various physical quantities in the process of sudden ground subsidence, thus providing comprehensive, accurate and real-time experimental data, ensuring the correlation and timing between various monitoring parameters, and providing a reliable basis for data analysis;

[0114] Analyze the correlation between the change of water head pressure in the aquifer and the amount of settlement. The decrease of water head pressure leads to the reduction of pore water in the aquifer, and the compression of soil causes settlement. The correlation analysis can reveal the coupling law between water level change and settlement process;

[0115] Determine the soil deformation and stress mutation points under load and negative pressure. The increase in load and negative pressure will cause the structural stability of the aquifer to gradually decrease. When the deformation accumulates to the limit value, the soil stress distribution will change suddenly, triggering the acceleration of ground settlement.

[0116] The critical value of water level, stress threshold and maximum settlement rate are obtained to form a risk warning plan. The critical values ​​of water level, stress and settlement rate are key control parameters in the process of land settlement. By quantitatively identifying them, the risk boundary of sudden settlement can be clearly defined. At the same time, the critical thresholds of water level, stress and settlement rate can be obtained, providing quantitative indicators and warning standards for land settlement risk assessment and prevention and control;

[0117] The risk warning model uses key data thresholds for dynamic monitoring. By comparing real-time parameter changes with risk thresholds, it can timely identify the potential risks of ground subsidence and instability. The risk warning program can effectively predict the risk of ground subsidence and instability, provide real-time warning and decision-making support for the prevention and control of sudden ground subsidence, and reduce engineering losses and geological disaster risks.

[0118] Please refer to the attached Figure 6 The present invention also provides an experimental method for a simulation box for sudden land subsidence in a plain area, comprising the following steps:

[0119] S1. Construct a ground subsidence simulation box in the plain area. The simulation box includes a simulation layer for the ground subsidence process in the plain area and a simulation layer for negative pressure in the deep strata. Through a highly restored physical model, the coupling relationship between multiple aquifers, aquicludes and deep cavities in the plain area is simulated to provide a basic environment for conducting ground subsidence experiments under the influence of multiple factors (aquifer water level, building load, karst cavity), ensuring the authenticity and comparability of the experimental results.

[0120] S2. A water head control system, a precipitation control system, a load system, a deep negative pressure simulation system and a sedimentation circulation system are set up inside the simulation box. Different experimental conditions are gradually applied through means such as water head control, precipitation replenishment, negative pressure drainage and load application to form a complete experimental environment, thereby achieving precise control of multiple factors in the process of ground subsidence and reproduction of experimental conditions, providing a highly simulated experimental environment;

[0121] S3. Adjust the water head pressure of the aquifer through the water head control system to simulate the decline of the water level in the aquifer. The decline of groundwater level is one of the important causes of land subsidence. By controlling the water head pressure, the decline of groundwater level caused by natural or artificial extraction can be simulated;

[0122] S4. Point loads and surface loads are applied through the load system to simulate the effects of building and road loads. The building loads cause compression deformation on the aquifer, which further causes the ground to settle. The effect of building pressure is gradually simulated through graded loading, thus achieving an accurate simulation of the coupling relationship between building loads and ground settlement, revealing the influence of load changes on the aquifer and soil structure.

[0123] S5. Start the deep negative pressure simulation system to simulate the water and sand loss process under the negative pressure condition of the karst cavity. Under the negative pressure condition, water and sand will flow downward, leading to the instability of the aquifer structure and ground subsidence. Accurately simulate the water and sand loss mechanism under the karst cavity condition, reveal the triggering mechanism of sudden ground subsidence, and provide a theoretical basis for prevention and control;

[0124] S6. Water and sand are filtered through the sedimentation circulation system to ensure the circulation of water resources. The water-sand separation system ensures the sustainable use of water resources during the experiment and maintains the stability of the system water cycle, thereby ensuring the continuity and efficiency of the experimental process and achieving efficient recycling of water resources;

[0125] S7. Sensors are placed inside the aquifer to collect data such as head pressure, soil stress, displacement and temperature in real time, and perform data analysis. The sensor system and camera equipment form a complete monitoring network, which collects multi-factor data in real time and directly reflects the key parameters in the ground subsidence process, thereby realizing real-time monitoring and accurate recording of the ground subsidence process, and providing comprehensive data support for the quantitative analysis of experimental results and mechanism research.

[0126] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A simulation box for sudden land subsidence in plain areas, characterized in that: The simulation box comprises: The simulation layer of land subsidence process in plain area is used to simulate the land subsidence process of aquifer and aquiclude; The deep formation negative pressure simulation layer is used to simulate the water and sand loss process under the negative pressure condition of the karst cavity; Head control system, which controls the head pressure of the aquifer by adjusting the water level in the water tank; Precipitation control system, used to simulate precipitation recharge processes of different intensities; Load system, which simulates building and road loads through point loads and surface loads; Sedimentation circulation system to achieve water-sand filtration and water resource circulation; The sensor system is used to collect data such as water head pressure, stress, displacement, temperature, etc., and cooperates with high-frequency camera equipment to record the entire experimental process.

2. The sudden land subsidence simulation box in a plain area according to claim 1 is characterized in that: The construction of a land subsidence simulation box in the plain area includes: The simulation box has a size of 2m×2m×3m, and the main frame of the simulation box is a steel structure; Organic glass plates are embedded around the simulation box to facilitate observation of internal structural changes; Three layers of aquifers are arranged in layers inside the simulation box, and the aquifers are filled with sand with different particle sizes; An impermeable layer is arranged between the aquifers. The impermeable layer is filled with low-permeability clay material and has a thickness of 0.15 to 0.25 m.

3. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The water head control system comprises: Three groups of water tanks are set on both sides of the simulation box, and the size of the water tanks is 2m×2m×0.1m 3 ; The water tank is connected to the three aquifers through free pipes, and the water level in the water tank is controlled by a float valve to control the head pressure; A water head pressure sensor is buried inside the aquifer to monitor the water head height and pressure changes in real time.

4. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The precipitation control system comprises: A spray device is evenly arranged on the top of the simulation box, and the spray device includes a plurality of nozzles with adjustable flow rates; The water source is supplied by a water pump, and the nozzle realizes precipitation replenishment of different intensities; The precipitation process is carried out in stages according to the experimental requirements to simulate different water level recharge conditions.

5. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The load system comprises: Arranging point loads and surface loads on the top of the simulation box; The point load simulates the effect of a single-story building through a concentrated load of 0.1 to 0.2 kg; The surface load is laid out by stacking 20×10×1cm steel plates to simulate high-rise building and road loads; Gradual loading: initially load 50% of the design load, and then gradually load in 10% increments until the ground settlement changes.

6. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The deep negative pressure simulation system comprises: A deep negative pressure simulation layer is arranged at the bottom of the simulation box, and a negative pressure environment is formed by a vacuum pump; A leakage hole with a diameter of 1 to 3 cm is set on the vertical plexiglass pipe; By opening the leakage hole and the negative pressure simulation valve, the rapid leakage of water and sand from the aquifer to the deep karst cavity is triggered; Adjust the negative pressure value of the vacuum pump to form different negative pressure conditions of -10 to -30 kPa.

7. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The precipitation circulation system comprises: A sedimentation tank and a water pump are arranged outside the simulation box; The sedimentation tank is used to filter the discharged water-sand mixture to complete solid-liquid separation; The filtered water is returned to the water head control system through a water pump to achieve the recycling of water resources.

8. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The sensor arrangement includes: A water head pressure sensor, a stress sensor, a displacement sensor and a temperature sensor are arranged inside the aquifer; The water head pressure sensor is used to monitor the water level change of the aquifer; The stress sensor is used to monitor the internal stress distribution of the soil; The displacement sensor is used to monitor ground settlement and deformation rate; High-frequency video equipment is used to record the entire experiment process and capture the dynamic changes in the stratum structure.

9. The sudden land subsidence simulation box in plain area according to claim 1 is characterized in that: The data analysis includes: Collect experimental data such as water head pressure, soil stress, displacement, flow and temperature; Analyze the correlation between the change of aquifer head pressure and the amount of sedimentation; Determine soil deformation and stress mutation points under load and negative pressure; The critical water level, stress threshold and maximum settlement rate are obtained to form a risk warning plan.

10. An experimental method for a simulation box for sudden land subsidence in plain areas, characterized in that: Using a simulation box for sudden land subsidence in a plain area as described in any one of claims 1 to 9 comprises the following steps: Constructing a plain area ground subsidence simulation box, the simulation box comprising a plain area ground subsidence process simulation layer and a deep stratum negative pressure simulation layer; A water head control system, a precipitation control system, a load system, a deep negative pressure simulation system and a sedimentation circulation system are arranged inside the simulation box; The water head pressure of the aquifer is adjusted by the water head control system to simulate the water level drop process of the aquifer; Apply point loads and surface loads through the load system to simulate the effects of building and road loads; Start the deep negative pressure simulation system to simulate the water and sand loss process under the negative pressure condition of the karst cavity; Water sand filtration is performed through a sedimentation circulation system to ensure water resource circulation; Sensors are placed inside the aquifer to collect data such as head pressure, soil stress, displacement and temperature in real time, and perform data analysis.

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