Ground fracture and ground subsidence test device and method for simulating multi-layer underground water level change

Abstract

The invention discloses a ground fissure and ground subsidence test device and method for simulating multi-layer underground water level change, the device comprises a box body, a fixed platform and a lifting platform are arranged in the box body, the box body is divided into two parts of space by the fixed platform and the lifting platform, and the two parts of space are arranged in the box body. A space positioned on the upper surfaces of the fixed platform and the lifting platform is used for laying a test soil layer; a plurality of water seepage pipe sets are buried in the test soil layer in the height direction, each water seepage pipe set is provided with a main opening and a plurality of water seepage holes, the main opening of each water seepage pipe set is connected with a water supply pipe, each water supply pipe is connected to a water supply assembly, each water supply pipe is in branch connection with a water drainage pipe, and each water drainage pipe is in branch connection with a water drainage pipe. Each drainage pipe is connected to water pumping equipment, a first valve is arranged on each water supply pipe and located between the water supply assembly and the corresponding drainage pipe, and a second valve is arranged on each drainage pipe.

Description

Technical Field

[0001] The invention belongs to the technical field of ground fissure and ground settlement simulation test, and in particular relates to a ground fissure and ground settlement test device and method for simulating multi-layer groundwater level changes. Background Art In the field of geology and environmental science, the study of the impact of groundwater activity on the stability of geological structures, especially the causal mechanism of groundwater-induced ground fissures and ground subsidence, has always been the focus of scientists. However, in this research field, there is still a lack of a comprehensive and accurate simulation test system platform to simulate and analyze ground fissures and ground subsidence under multi-layer groundwater conditions. The complexity of multi-layer groundwater systems, including the distribution of different aquifers, differences in permeability, and dynamic changes in water flow, all pose challenges to simulation experiments.

[0002] Although some tentative simulation test devices have been proposed, such as a ground fissure test device and method for simulating fracture dislocation and groundwater changes disclosed in the patent application with publication number CN110954680A, the test device mainly uses a water tank as a water injection system, utilizes the gravitational potential energy of the water body and controls the water inlet process of the test model box through a water supply valve. However, this water inlet method and its related structural design are relatively simple, and fail to fully consider the uneven permeability characteristics of the water body in a complex geological structure. In addition, the test device does not consider the specific layout of the water distribution pipeline and the water inlet pipe, and the drainage device is too simple, with only one drainage outlet. Since the flow and discharge of groundwater in a multi-layer aquifer is a complex process, the design of a single drainage outlet is obviously unable to fully simulate this process, thereby limiting the application effect of the device in simulating ground fissures and ground subsidence under multi-layer groundwater conditions, and is prone to uneven drainage problems, affecting the accuracy of the test results. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a ground fissure and ground settlement test device and method for simulating multi-layer groundwater level changes, which aims to solve the above problems.

[0004] In order to solve the above technical problems, the present invention is implemented by the following technical solutions: A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes, comprising a box body, wherein a fixed platform and a liftable platform are arranged in the box body, wherein the fixed platform and the liftable platform jointly divide the box body into two spaces, and the space located on the upper surfaces of the fixed platform and the liftable platform is used for laying out a test soil layer; a plurality of seepage pipe groups are buried in the test soil layer along the height direction, each of the seepage pipe groups is provided with a main opening and a plurality of seepage holes, the main opening of each seepage pipe group is connected to a water supply pipe, each of the water supply pipes is connected to a water supply assembly, each of the water supply pipes is branched and connected to a drainage pipe, each of the drainage pipes is connected to a pumping device, a first valve is provided on each of the water supply pipes between the water supply assembly and the drainage pipe, and a second valve is provided on each of the drainage pipes.

[0005] Furthermore, the water supply assembly includes a water supply device, a water tank bracket and a water tank arranged on the water tank bracket, the water supply device is connected to the water inlet of the water tank through a first pipe, the bottom water outlet of the water tank is vertically connected to a second pipe, and each of the water supply pipes is connected to the second pipe.

[0006] Furthermore, moving wheels are provided at the bottom of the water tank bracket.

[0007] Furthermore, the seepage pipe group is composed of at least two seepage pipes connected in parallel to form a loop, and each seepage pipe is provided with a plurality of seepage holes.

[0008] Furthermore, a plurality of jacks are arranged at the bottom of the liftable platform, and a limited position connecting rod mechanism is hinged between the liftable platform and the bottom of the box.

[0009] Furthermore, the test device also includes an anti-overturning device located on one side of the box body, the anti-overturning device includes a support frame, a plurality of inclined brackets inclined to the box body are arranged in the support frame, each of the inclined brackets is provided with a slider, and a connecting frame is connected between the slider on each of the inclined brackets and the box body.

[0010] Furthermore, soil material transport equipment is arranged on the top of the box.

[0011] Furthermore, the soil material transportation equipment includes triangular brackets arranged on both sides of the top of the box body, the triangular brackets are provided with horizontal slide rails, the horizontal slide rails are provided with a sliding vehicle, and the sliding vehicle is provided with a hook.

[0012] Furthermore, the test soil layer is composed of sandy soil layers and silty clay layers arranged alternately from bottom to top, and the seepage pipe group is buried in the corresponding sandy soil layer.

[0013] A method for testing ground fissures and ground settlement by simulating multi-layer groundwater level changes, using a ground fissure and ground settlement testing device simulating multi-layer groundwater level changes, comprising: Laying a test soil layer on the upper surfaces of the fixed platform and the liftable platform, burying a plurality of the seepage pipe groups in the test soil layer along the height direction, burying a first detection sensor in the test soil layer, and arranging a second detection sensor above the box, wherein the second detection sensor is used to detect ground subsidence; Open the first valve, close the second valve, use the water supply assembly and the water supply pipe to descend toward the seepage pipe group to simulate the ground fissure, and use the first detection sensor and the second detection sensor to detect data in real time; The first valve is closed, the second valve is opened, the water in the soil layer is pumped out by using the pumping equipment and the drainage pipe, and the data is detected in real time by using the first detection sensor and the second detection sensor.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides a ground fissure and ground settlement test device for simulating multi-layer groundwater level changes. By burying multiple seepage pipe groups in the test soil layer along the height direction, each seepage pipe group can independently control water injection and drainage, thereby realizing accurate simulation of multi-layer groundwater level changes, taking full account of the uneven permeability characteristics of groundwater in complex geological structures, and making the simulation test closer to the actual situation. Each seepage pipe group is equipped with a water supply pipe, a drainage pipe and corresponding valves, which can accurately control the process of water injection and drainage, and can monitor the changes of ground fissures and ground settlement in real time, thereby greatly improving the accuracy of the test results. By controlling the lifting and lowering of the liftable platform, the generation and expansion process of ground fissures can be flexibly simulated. At the same time, combined with water injection and drainage operations, the influence of groundwater activity on ground settlement can be further simulated. The structural design of the device of the present invention is reasonable, and the connection between the components is tight and easy to operate. During the test, the control of water injection and drainage can be achieved by opening or closing the corresponding valves, and the operation is simple and quick.

[0015] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of a ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to the present invention; Figure 2 Schematic diagram of the test coating; Figure 3 This is a schematic diagram of the layout of the laser displacement meter (surface displacement meter) in the embodiment; Figure 4 A schematic diagram of the layout of the soil pressure sensor (pressure box) in the embodiment; Figure 5 A schematic diagram of the layout of the optical fiber (and the soil pressure box) in the embodiment; Figure 6 , Figure 7 and Figure 8 It is a schematic diagram of the layout of pore pressure sensors and water meters at different depths in the embodiment.

[0018] In the figure: 1-box; 2-fixed platform; 3-liftable platform; 4-test soil layer; 40-sandy soil layer; 41-silty clay layer; 5-seepage pipe group; 6-water supply pipe; 7-water supply assembly; 70-water supply equipment; 71-water tank bracket; 72-water tank; 73-first pipeline; 74-second pipeline; 75-moving wheel; 8-drain pipe; 9-pumping equipment; 10-first valve; 11-second valve; 12-jack; 13-limiting connecting rod mechanism; 14-anti-overturning device; 140-support frame; 141-tilt bracket; 142-sliding block; 143-connecting frame; 15-soil transportation equipment; 150-triangular bracket; 151-horizontal slide rail; 152-sliding vehicle; 153-hook. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are 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.

[0020] like Figure 1 and Figure 2As shown, an embodiment of the present invention provides a ground fissure and ground settlement test device for simulating multi-layer groundwater level changes, including a box body 1, a fixed platform 2 and a liftable platform 3 are arranged in the box body 1, the fixed platform 2 and the liftable platform 3 jointly divide the box body 1 into two spaces, and the space located on the upper surfaces of the fixed platform 2 and the liftable platform 3 is used to arrange a test soil layer 4; a plurality of seepage pipe groups 5 are buried in the test soil layer 4 along the height direction, each of the seepage pipe groups 5 is provided with a main opening and a plurality of seepage holes, the main opening of each seepage pipe group 5 is connected to a water supply pipe 6, each water supply pipe 6 is connected to a water supply assembly 7, each water supply pipe 6 is branched and connected to a drainage pipe 8, each drainage pipe 8 is connected to a pumping device 9, a first valve 10 is provided on each water supply pipe 6 between the water supply assembly 7 and the drainage pipe 8, and a second valve 11 is provided on each drainage pipe 8.

[0021] Specifically, the box 1 is made of high-strength, corrosion-resistant materials to ensure durability during long-term testing. The box 1 is made of transparent materials for easy observation. The size of the box 1 is designed according to the needs of the simulation test to accommodate enough test soil layers 4 and allow enough space for observation and measurement. The fixed platform 2 is located near the bottom of the box 1 and is an immovable structure used to support the test soil layer 4 and the seepage pipe group 5. The surface of the fixed platform 2 is flat to ensure the uniform laying of the test soil layer 4. The liftable platform 3 is installed near the bottom of the box 1 through a mechanical lifting mechanism, and the height can be adjusted according to the test requirements to simulate the process of ground fissure generation. It should be noted that the height of the liftable platform 3 is not higher than the height of the fixed platform 2. The test soil layer 4 is based on the geological structure characteristics of the study area, using soil materials of different properties (such as sand, clay, etc.) mixed in a certain proportion to simulate the real geological layer. The test soil layer 4 is laid in layers on the fixed platform 2 and the liftable platform 3. Each seepage pipe group 5 is composed of a plurality of slender seepage pipes in parallel, and seepage holes are evenly distributed on each pipe to simulate the infiltration process of groundwater in the soil. The main opening of the seepage pipe group 5 is connected to the water supply assembly 7 through the water supply pipe 6 to achieve water volume control. It should be noted that the arrangement of the seepage pipe group 5 in the test soil layer 4 should take into account the distribution and permeability differences of the aquifer in the actual geological structure to achieve a more realistic simulation effect. The water supply assembly 7 is composed of a water pump and a control system, which can adjust the water supply volume and water supply rate according to the test requirements. The water supply assembly 7 is connected to the main opening of each seepage pipe group 5 through the water supply pipe 6 to ensure that the water flow can be evenly distributed to different depths and positions of the test soil layer 4. The first valve 10 provided on the water supply pipe 6 is used to control the water supply to the seepage pipe group 5, and the second valve 11 on the drain pipe 8 is used to adjust the drainage volume, and the two together constitute a water flow control system. By adjusting the opening and closing states of the first valve 10 and the second valve 11, the flow and discharge process of groundwater in different aquifers can be simulated, including infiltration, accumulation and discharge, etc. The pumping device 9 is used to extract water from the seepage pipe group 5 when necessary to simulate the decline of the groundwater level.

[0022] This embodiment provides a ground fissure and ground settlement test method for simulating multi-layer groundwater level changes, specifically: According to the test requirements, a test soil layer 4 is laid on the upper surface of the fixed platform 2 and the liftable platform 3, and several seepage pipe groups 5 are buried in the soil layer along the height direction. At the same time, a first detection sensor is buried in the test soil layer 4, and a second detection sensor is arranged above the box 1.

[0023] During the water injection phase, the first valve 10 is opened, the second valve 11 is closed, the water supply assembly 7 is started, and water is injected into the soil layer where the seepage pipe group 5 is located through the water supply pipe 6. The first detection sensor and the second detection sensor are used to detect the soil moisture change, the development of ground fissures and the ground settlement in real time. The water injection speed and pressure are adjusted according to the detection results to simulate the groundwater activity under different conditions.

[0024] In the ground fissure simulation stage, after the water injection reaches the predetermined condition, the liftable platform 3 is controlled to descend to a certain height to simulate the formation process of the ground fissure. At the same time, the first detection sensor and the second detection sensor are continuously used to detect data in real time to observe the development of the ground fissure and the change of ground settlement.

[0025] In the drainage stage, the first valve 10 is closed, the second valve 11 is opened, the pumping equipment 9 is started, and the water in the soil layer is pumped out through the drainage pipe 8. The first detection sensor and the second detection sensor are used to detect the change of soil moisture, the closure of ground fissures and the recovery of ground settlement in real time. The pumping speed and duration are adjusted according to the detection results to simulate the process of groundwater level decline under different conditions. Exemplarily, the pumping equipment 9 is a water pump.

[0026] Finally, the data from the first detection sensor and the second detection sensor during the test were collected and sorted out to analyze the impact of groundwater activity on the stability of geological structures, as well as the causes of ground fissures and ground subsidence.

[0027] In one implementable embodiment, the water supply assembly 7 includes a water supply device 70, a water tank bracket 71, and a water tank 72 arranged on the water tank bracket 71. The water supply device 70 is connected to the water inlet of the water tank 72 through a first pipe 73, and the bottom water outlet of the water tank 72 is vertically connected to a second pipe 74, and each water supply pipe 6 is connected to the second pipe 74.

[0028] Specifically, the water supply assembly 7 is used to provide a stable water flow to the seepage pipe group 5 to simulate groundwater activities under different conditions. The assembly includes a water supply device 70, a water tank bracket 71, and a water tank 72 arranged on the water tank bracket 71. The water supply device 70 is a power device for providing a water source, which can be a water pump, a booster pump, etc., and its function is to inject water into the water tank 72 and maintain a certain water pressure to ensure that the water flow can smoothly enter the seepage pipe group 5. The water tank bracket 71 is a structural member supporting the water tank 72 to ensure that the water tank 72 remains stable during the test to avoid affecting the water supply effect due to shaking or tilting. The water tank 72 is a container for storing and regulating water flow, such as stainless steel, fiberglass, etc. The capacity of the water tank 72 is selected according to the test requirements to ensure that sufficient water can be provided during a long test. The water inlet of the water tank 72 is connected to the water supply device 70 through a first pipe 73 to receive the water flow from the water supply device 70. The bottom water outlet of the water tank 72 is vertically connected with a second pipe 74 for conveying water to each water supply pipe 6. The first pipe 73 is a pipe connecting the water supply device 70 and the water tank 72 to ensure that the water can smoothly enter the water tank 72. Accessories such as valves or flow meters can be set on the first pipe 73 to adjust and control the flow rate and pressure of the water. The second pipe 74 is a pipe connecting the water tank 72 and each water supply pipe 6 to ensure that the water can be evenly distributed to each water supply pipe 6. Accessories such as water distributors or diverter valves can be set on the second pipe 74 to evenly distribute the water to each seepage pipe group 5.

[0029] Before the test begins, the water supply device 70 is first started to inject water into the water tank 72. When the water level in the water tank 72 reaches a predetermined height, the water supply device 70 stops working. Then, the first valve 10 is opened, the second valve 11 is closed, and the water in the water tank 72 enters each water supply pipe 6 through the second pipe 74, and then penetrates into the test soil layer 4 through the seepage holes on the seepage pipe group 5. By adjusting the working state of the water supply device 70 and the valve on the first pipe 73, the flow rate and pressure of the water flow can be controlled to simulate groundwater activities under different conditions. During the test, the working state of the water supply device 70 and the water level in the water tank 72 can be adjusted as needed to simulate the changes in different groundwater levels. At the same time, by observing the data changes of the first detection sensor and the second detection sensor, the soil moisture changes, the development of ground fissures and the ground subsidence are monitored in real time, so as to analyze the influence mechanism of groundwater activities on the stability of geological structures.

[0030] In one achievable manner, a moving wheel 75 is provided at the bottom of the water tank bracket 71, and the moving wheel 75 enables the entire water supply assembly 7 to be easily moved and adjusted in position. The moving wheel 75 is made of wear-resistant and corrosion-resistant rubber or plastic to ensure good durability during long-term use. In order to facilitate the fixing of the position of the water tank bracket 71 during the test, the moving wheel 75 is equipped with a locking function. When the water tank bracket 71 needs to be fixed, it is only necessary to lock the moving wheel 75 to prevent it from sliding or moving. In order to meet the demand of moving the water tank bracket 71 in different directions, some of the moving wheels 75 are designed to be steerable, that is, they can rotate 360 ​​degrees or rotate within a certain angle.

[0031] In one achievable manner, the seepage pipe group 5 is formed by at least two seepage pipes connected in parallel to form a loop, and each seepage pipe is provided with a plurality of seepage holes. The seepage pipe group 5 is used to simulate the infiltration process of groundwater in the soil. That is to say, the seepage pipe is the basic unit of the seepage pipe group 5, and is made of corrosion-resistant and high-pressure-resistant materials, such as stainless steel, PE pipe, etc. The length and diameter of the seepage pipe are selected according to the test requirements to ensure that the test area can be covered and the requirements of the seepage simulation can be met. The seepage pipes in the seepage pipe group 5 are connected in parallel to form a loop, which improves the uniformity and stability of the seepage. Each seepage pipe is provided with a plurality of seepage holes for uniformly infiltrating water into the test soil layer. The size, number and distribution of the seepage holes are designed according to the test requirements to ensure that the water flow can infiltrate at a predetermined speed and direction. The shape of the seepage hole can be circular, elliptical or other shapes to adapt to different infiltration modes and soil conditions.

[0032] During the test, the water provided by the water supply assembly 7 enters the seepage pipe group 5 through the second pipe 74. When the water flows in the seepage pipe, it penetrates into the test soil layer 4 through the seepage holes, simulating the infiltration process of groundwater in the soil. Since the seepage pipe group 5 adopts a parallel loop design, the water flow can be evenly distributed on each seepage pipe, thereby improving the uniformity and stability of the seepage.

[0033] In one achievable manner, a plurality of jacks 12 are provided at the bottom of the liftable platform 3, and a limited position link mechanism 13 is hinged between the liftable platform 3 and the bottom of the box 1. Specifically, the jack 12 is a key component installed at the bottom of the liftable platform 3, and is used to realize the lifting function of the platform. The number and layout of the jacks 12 are designed according to the size and weight of the liftable platform 3 to ensure the stability of the lifting process. Exemplarily, the type of the jack 12 can be hydraulic, mechanical or electric. During the lifting process, the jack 12 ensures that the liftable platform 3 rises or falls smoothly and evenly through synchronous control. The limit link mechanism 13 is an articulated mechanism connected between the liftable platform 3 and the bottom of the box 1, which is used to limit the lifting range of the liftable platform 3 and prevent it from over-tilting. The limit link mechanism 13 is composed of a plurality of links and hinge points. During the lifting process, the limit link mechanism 13 plays a guiding and limiting role to ensure that the liftable platform 3 moves smoothly within a predetermined trajectory.

[0034] In one possible implementation, the test device further includes an anti-overturning device 14 located on one side of the box body 1, and the anti-overturning device 14 includes a support frame 140, and a plurality of inclined brackets 141 inclined toward the box body 1 are arranged in the support frame 140, and a slider 142 is arranged on each inclined bracket 141, and a connecting frame 143 is connected between the slider 142 on each inclined bracket 141 and the box body 1. The anti-overturning device 14 is to prevent the box body 1 from overturning or becoming unstable due to various reasons (such as a sharp change in the groundwater level, uneven settlement of the soil, etc.) during the test.

[0035] Specifically, the support frame 140 is the main structure of the anti-overturning device 14, which is used to support and fix the tilt bracket 141. The support frame 140 is made of metal materials, such as steel or aluminum alloy, to ensure that it has sufficient strength. The shape and size of the support frame 140 are designed according to the size and shape of the box 1 to ensure that it can fit tightly and effectively support the box 1. The tilt bracket 141 is connected to the support frame 140 to provide a tilting support force in the direction of the box 1. The number and layout of the tilt bracket 141 are designed according to the weight and stability requirements of the box 1 to ensure that sufficient support force can be provided during the test. The tilt bracket 141 adopts an adjustable design so that it can be adjusted according to different test conditions and the tilt of the box 1. The slider 142 is a moving part arranged on the tilt bracket 141, which is used to cooperate with the connecting frame 143 to achieve a flexible connection between the box 1 and the anti-overturning device 14. The connecting frame 143 is a bridge connecting the slider 142 and the box 1, which is used to transmit the support force of the anti-overturning device 14 to the box 1. The connecting frame 143 is made of metal material to ensure that it has sufficient strength.

[0036] During the test, when the box 1 is affected by external factors such as groundwater activity and soil settlement, the anti-overturning device 14 begins to work. The tilting bracket 141 provides tilting support force to the box 1 through the slider 142 and the connecting frame 143 to prevent it from overturning or becoming unstable. At the same time, since the slider 142 and the connecting frame 143 are designed to be adjustable, they can be adjusted according to different test conditions and the tilt of the box 1 to ensure that the anti-overturning device 14 can always provide effective support force. The anti-overturning device 14 prevents the box 1 from overturning or becoming unstable during the test, thereby ensuring the smooth progress of the test and the safety of personnel and equipment.

[0037] In one possible implementation, a soil material transport device 15 is provided on the top of the box 1. The soil material transport device 15 is used to transport soil or test materials to the top of the box 1, so as to facilitate loading into the box 1. During the test, the soil material transport device 15 starts to work and transports soil from the ground or low place to the top of the box 1, thereby improving the operating efficiency of the test device and reducing the labor intensity of the operator.

[0038] In one achievable manner, the soil material transport equipment 15 includes triangular brackets 150 disposed on both sides of the top of the box body 1 , the triangular brackets 150 are provided with horizontal slide rails 151 , the horizontal slide rails 151 are provided with a sliding vehicle 152 , and the sliding vehicle 152 is provided with a hook 153 .

[0039] Specifically, the triangular bracket 150 is the supporting structure of the soil material transporting equipment 15, and is arranged on both sides of the top of the box body 1. The triangular bracket 150 adopts the principle of triangular stability to ensure the stability and load-bearing capacity of the structure. The horizontal slide rail 151 is arranged on the triangular bracket 150, and is used to support and guide the movement of the sliding vehicle 152. The sliding vehicle 152 is a mobile platform arranged on the horizontal slide rail 151, and is used to carry and transport soil materials. Exemplarily, the bottom of the sliding vehicle 152 is provided with rollers or sliders matching the horizontal slide rail 151, so that it can slide steadily and smoothly during the movement. The hook 153 is a component arranged on the sliding vehicle 152, and is used to suspend and lift soil materials.

[0040] During the test, the operator first placed the soil on the hook 153, and then operated the skid trolley 152 to move on the horizontal slide rail 151 to transport the soil to the top of the box 1. Then, the operator adjusted the height and position of the hook 153 to drop the soil into the box 1. During the whole process, the tripod support 150 provided a stable support to ensure the stability of the soil transport equipment 15.

[0041] The soil material transport equipment 15 can transport soil materials continuously and efficiently, greatly improving the efficiency of the test. The automated operation of the soil material transport equipment 15 greatly reduces the labor intensity of the operator and improves the comfort of the test.

[0042] In one achievable manner, the test soil layer 4 is alternately arranged with sandy soil layers 40 and silty clay layers 41 from bottom to top, and the seepage pipe group 5 is buried in the corresponding sandy soil layer 40. Specifically, the test soil layer 4 is alternately arranged with sandy soil layers 40 and silty clay layers 41 from bottom to top, simulating the multi-layer geological structure commonly seen in nature, and studying the response characteristics of different soil layers under changes in groundwater levels. The seepage pipe group 5 is buried in the corresponding sandy soil layer 40. Since the sandy soil layer 40 has good water permeability, the seepage pipe group 5 can more effectively introduce or discharge water into or out of the test soil layer.

[0043] It can be seen that the test device provided in the above embodiment can be used for testing without preset cracks (fractures) or for testing with preset cracks to simulate the effect of changes in the water level of multiple layers of underground confined water on the characteristics of ground fissure rupture and expansion and ground subsidence. The test device is mainly used to simulate the evolution of ground fissures and ground subsidence when drainage and seepage occur in underground aquifers under natural conditions; to simulate the evolution of ground fissure rupture and expansion, and ground subsidence deformation under the action of natural seepage recharge (drainage) or human extraction (recharge) of groundwater.

[0044] The present invention provides a ground fissure and ground settlement test method for simulating multi-layer groundwater level changes, which is as follows: Build a ground fissure and ground settlement test device that simulates multi-layer groundwater level changes, and ensure that the fixed platform 2 and the liftable platform 3 are firmly installed in the box 1. Lay the test soil layer 4 on the upper surface of the fixed platform 2 and the liftable platform 3, and simulate the multi-layer geological structure by alternating the sand layer 40 and the silty clay layer 41. Bury several seepage pipe groups 5 in the test soil layer 4 along the height direction, and ensure that the main opening of the seepage pipe group 5 is connected to the water supply pipe 6, and the water supply pipe 6 is connected to the water supply component 7. Bury the first detection sensor in the test soil layer 4 to monitor the stress, strain, pore water pressure and other parameters inside the soil layer. Arrange the second detection sensor above the box 1 to detect ground settlement.

[0045] Water injection stage: open the first valve 10 and close the second valve 11. Use the water supply assembly 7 and the water supply pipe 6 to inject water into the soil layer where the seepage pipe group 5 is located to simulate the rise of the groundwater level. Observe and record the data of the first detection sensor and the second detection sensor in real time, and analyze the stress, strain, pore water pressure changes and ground settlement inside the soil layer.

[0046] Ground fissure simulation stage: After the water injection stage, the liftable platform 3 is controlled to descend to simulate the ground fissures caused by ground subsidence. The data of the first detection sensor and the second detection sensor are observed and recorded in real time to analyze the stress and strain changes inside the soil layer and the ground subsidence during the formation of the ground fissures.

[0047] Drainage stage: close the first valve 10 and open the second valve 11. Use the pumping equipment 9 and the drainage pipe 8 to pump out the water in the soil layer to simulate the drop in the groundwater level. Observe and record the data of the first detection sensor and the second detection sensor in real time, and analyze the stress, strain, pore water pressure recovery and ground settlement recovery in the soil layer during the drainage process.

[0048] The data of the first detection sensor and the second detection sensor in the water injection stage, ground fissure simulation stage and drainage stage are collated and analyzed. Based on the data analysis results, the stress, strain, pore water pressure change and ground settlement of the soil layer under different groundwater level changes are studied. The changes in the internal mechanical properties of the soil layer during the formation and recovery of ground fissures are analyzed.

[0049] In one embodiment, if Figure 3 As shown in the figure, the laser displacement meter is arranged symmetrically along the central axis of the box body with four monitoring displacement lines. The central axis is also arranged with monitoring displacement lines, which are evenly arranged at a distance of 0.4 m. Each monitoring line is arranged with 11 laser displacement meters, and a total of 55 are arranged. The laser monitoring point extends along the top central axis. The distance between the monitoring line at the central axis and the upper and lower adjacent monitoring lines is 0.2 m, and the adjacent distance between the upper and lower side lines is 0.4 m.

[0050] In one embodiment, if Figure 4 As shown, when burying the soil pressure sensor, first compact and level the bottom of the hole, and lay a layer of screened fine sand on the bottom of the hole to ensure that the soil pressure sensor is evenly stressed during the crack activity. When placing it, the soil pressure sensor that measures the vertical pressure faces upward and is placed horizontally, and the soil pressure sensor that measures the horizontal pressure faces the preset crack direction and is placed vertically. Finally, screened fine sand is laid around the pressure box and compacted to ensure that the surface of the pressure box is evenly pressurized and to avoid fluctuations in the pressure box readings. At this time, the soil pressure sensor is buried.

[0051] In one embodiment, if Figure 5 As shown in the figure, the burial of the optical fiber is similar to that of the pressure box. A channel is excavated along the length of the box to the predetermined burial stratum height. The soil trough is kept as straight as possible to avoid distortion. At the same time, a mixture of kaolin and fine sand is spread on the bottom of the optical fiber to level the bottom and increase the coupling between the soil and the optical fiber and the sensitivity of the optical fiber deformation. At the same time, the positions of the preset crack projections and other fixed points are recorded to facilitate the later comparative analysis of the strain changes of the optical fiber. Then, the optical fiber is fixed to the soil layer in sections through acrylic plates. The optical fiber on both sides of the model is wrapped with a PVC tube with a diameter of 15 cm to achieve the transformation of the burial direction and pre-tensioning of the optical fiber.

[0052] In one embodiment, if Figure 6 , Figure 7 and Figure 8 As shown in the figure, the pore pressure sensor and moisture meter are buried by drilling with a ring knife. At the buried point, a ring knife is used to press and drill holes. After reaching the required depth or elevation, some clean sand is first filled at the bottom of the hole, and then the probe is placed, and then sand is filled around the probe. Finally, the upper part of the borehole is sealed with an expansive clay ball or a dry clay ball, so that the probe measures the pore water pressure of the soil layer at the elevation. The technical key to burying the pore water pressure probe is to first ensure that the sand padding around the probe is unobstructed, and secondly to cut off the downward leakage from the upper part of the borehole. The pore pressure sensor is arranged in the center of the silty clay aquifer and near the top and bottom plates of the aquifer.

[0053] In the ground fissure and ground subsidence test method simulating fault dislocation and groundwater changes adopted in the above-mentioned embodiment, a physical model test of ground fissures and ground subsidence expansion induced by simulating the coupling effect of fault dislocation and multi-layer groundwater level changes is carried out. Different monitoring instruments, multiple positions, multiple arrangements and different layouts are used to reproduce the formation, expansion and evolution process of ground fissures and ground subsidence, and the development of the width of ground fissures and ground subsidence in the simulated stratum, the simulated stratum surface settlement, and the changes in stress, strain and pore water pressure in the simulated stratum are obtained, thereby providing an analytical basis and physical model support for the formation mechanism and active expansion analysis of ground fissures and ground subsidence.

[0054] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "connected", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0058] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean 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 present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0059] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A ground fissure and ground settlement test device simulating multi-layer groundwater level changes, characterized in that: The invention comprises a box (1), wherein a fixed platform (2) and a liftable platform (3) are arranged in the box (1), wherein the fixed platform (2) and the liftable platform (3) together divide the box (1) into two spaces, wherein the space located on the upper surfaces of the fixed platform (2) and the liftable platform (3) is used to arrange a test soil layer (4); wherein a plurality of seepage pipe groups (5) are buried in the test soil layer (4) along the height direction, wherein each of the seepage pipe groups (5) is provided with a main opening and a plurality of seepage holes, wherein the main opening of each of the seepage pipe groups (5) is connected to a water supply pipe (6), wherein each of the water supply pipes (6) is connected to a water supply assembly (7), wherein a branch of each of the water supply pipes (6) is connected to a drainage pipe (8), wherein each of the drainage pipes (8) is connected to a water pumping device (9), wherein each of the water supply pipes (6) is provided with a first valve (10) between the water supply assembly (7) and the drainage pipe (8), and wherein each of the drainage pipes (8) is provided with a second valve (11).

2. A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 1, characterized in that: The water supply assembly (7) comprises a water supply device (70), a water tank bracket (71), and a water tank (72) arranged on the water tank bracket (71); the water supply device (70) is connected to a water inlet of the water tank (72) via a first pipe (73); a bottom water outlet of the water tank (72) is vertically connected to a second pipe (74); and each of the water supply pipes (6) is connected to the second pipe (74).

3. A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 2, characterized in that: The bottom of the water tank bracket (71) is provided with moving wheels (75).

4. A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 1, characterized in that: The seepage pipe group (5) is composed of at least two seepage pipes connected in parallel to form a loop, and each seepage pipe is provided with a plurality of seepage holes.

5. The ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 1, characterized in that: A plurality of jacks (12) are arranged at the bottom of the liftable platform (3), and a limited position connecting rod mechanism (13) is hingedly connected between the liftable platform (3) and the bottom of the box body (1).

6. A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 1, characterized in that: The test device also includes an anti-overturning device (14) located on one side of the box body (1), the anti-overturning device (14) including a support frame (140), a plurality of inclined brackets (141) inclined toward the box body (1) are arranged in the support frame (140), a sliding block (142) is arranged on each of the inclined brackets (141), and a connecting frame (143) is connected between the sliding block (142) on each of the inclined brackets (141) and the box body (1).

7. A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 1, characterized in that: Soil material transport equipment (15) is provided on the top of the box body (1).

8. A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 7, characterized in that: The soil material transport equipment (15) comprises triangular brackets (150) arranged on both sides of the top of the box body (1), the triangular brackets (150) are provided with horizontal slide rails (151), the horizontal slide rails (151) are provided with a sliding vehicle (152), and the sliding vehicle (152) is provided with a hook (153).

9. The ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to claim 1, characterized in that: The test soil layer (4) is composed of sandy soil layers (40) and silty clay layers (41) arranged alternately from bottom to top, and the seepage pipe group (5) is buried in the corresponding sandy soil layer (40).

10. A ground fissure and ground settlement test method simulating multi-layer groundwater level changes, characterized in that: A ground fissure and ground settlement test device for simulating multi-layer groundwater level changes according to any one of claims 1 to 9, comprising: A test soil layer (4) is laid on the upper surfaces of the fixed platform (2) and the liftable platform (3), and a plurality of the seepage pipe groups (5) are buried in the test soil layer (4) along the height direction, and a first detection sensor is buried in the test soil layer (4), and a second detection sensor is arranged above the box (1), wherein the second detection sensor is used to detect ground subsidence; Open the first valve (10), close the second valve (11), use the water supply assembly (7) and the water supply pipe (6) to inject water into the soil layer where the seepage pipe group (5) is located, and use the first detection sensor and the second detection sensor to detect data in real time; Controlling the liftable platform (3) to descend to simulate ground fissures, and using the first detection sensor and the second detection sensor to detect data in real time; The first valve (10) is closed, the second valve (11) is opened, the water in the soil layer is pumped out using the pumping equipment (9) and the drainage pipe (8), and the data is detected in real time using the first detection sensor and the second detection sensor.

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