Trench wall collapse simulation device

Abstract

The application discloses a kind of slot wall collapse simulation device, including box, water inlet hole plate, water outlet hole plate, cover plate, air connection water inlet pipe, displacement sensor;Multiple pore water pressure sensors;Cover plate is installed above first area, and is used to close the top of first area;Air connection water inlet pipe is communicated with first area inside;Multiple pore water pressure sensors are placed in the inside of soil sample in second area;Displacement sensor is installed in simulation tank.The device can simulate the migration of water flow in soil sample under different groundwater depths by pressurization, and then cause the process of soil sample collapse;It can test the stability of soil layer conditions in construction area under the action of groundwater, quantitatively evaluate the porosity and water erosion resistance of soil sample;At the same time, it can also approximately infer the depth of possible hole wall collapse, for engineering construction reference, to judge whether soil sample reinforcement is needed and propose appropriate soil sample reinforcement method, reduce the impact of hole wall collapse on project progress.

Description

Technical Field

[0001] This invention relates to the field of underground continuous wall collapse simulation technology, and in particular to a trench wall collapse simulation device. Background Technology

[0002] Diaphragm walls, as a foundation treatment technology, possess advantages such as high rigidity, high strength, and good water resistance, and are widely used in deep foundation pits and water-rich strata. Maintaining the stability of the trench walls during construction is crucial for ensuring smooth construction and project quality. The geological conditions of the construction area are a key factor affecting trench wall stability, especially in water-rich strata where the presence of groundwater further deteriorates the geological conditions. Particularly after trenching, the original stress state of the soil samples is disrupted, creating weak points along the trench walls, which frequently lead to trench wall collapses.

[0003] Therefore, it is necessary to develop a tank wall collapse simulation device to simulate wall collapse, so that technicians in related fields can obtain more simulation data to design better tank wall structures. Summary of the Invention

[0004] The purpose of this invention is to design a trench wall collapse simulation device to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions:

[0006] The tank wall collapse simulation device includes:

[0007] The box has an opening at the top; the box includes a front panel, a rear panel, a left side panel, a right side panel, and a bottom panel;

[0008] Inlet orifice plate;

[0009] The water outlet plate and the water inlet plate each have multiple horizontal through holes. Both are located inside the tank, dividing the tank space into three zones: the first zone is between the left side plate and the water inlet plate, the second zone is between the water inlet plate and the water outlet plate, and the third zone is between the water outlet plate and the right side plate. Water is placed in the first zone; a soil sample is placed in the second zone, with a simulation tank in the center of the soil sample; the third zone is the water outlet space.

[0010] Cover plate; The cover plate is installed above the first area and is used to close the top of the first area;

[0011] A gas inlet pipe for water or high-pressure gas intake; the gas inlet pipe is connected to the first area.

[0012] Multiple pore water pressure sensors; multiple pore water pressure sensors are placed inside the soil sample in the second region;

[0013] A displacement sensor used for simulating tank displacement measurement; the displacement sensor is installed inside the simulated tank.

[0014] The beneficial effects of this invention are as follows:

[0015] (1) Modular components, compact and easy to move

[0016] External devices such as gas cylinders, flow meters, pore water pressure sensors, and displacement sensors can be selected and replaced according to different usage needs. The assembly method is detachable for easy transportation. The main body of the device is composed of machinable sheet metal, allowing for high design freedom, simple structure, sturdiness, and durability, and can be matched with various construction conditions.

[0017] (2) High visualization, real-time detection

[0018] The tank is made of transparent material, allowing macroscopic changes in the tank walls to be observed with the naked eye. Combined with real-time detection by sensors, it can combine detailed parameter changes with macroscopic performance, highlighting the entire process from water injection to tank wall collapse.

[0019] (3) Numerous test parameters, accurate data, and comprehensive evaluation of soil sample performance.

[0020] Different sensors are used to comprehensively detect pore water pressure, total water flow, and trench wall condition at different locations. Changes in pore water pressure are used to infer changes in pore structure and water flow velocity within soil samples at different locations. Changes in water flow are used to infer the overall state of the soil sample, including internal pores and the number of water flow paths. Displacement sensors are used to analyze the state of the trench wall at different times, which can reveal the process by which small soil particles detach from the soil sample, leading to the collapse of the entire trench wall. The parameters and conclusions obtained from these three methods are combined to analyze the entire process of soil sample collapse at both the microscopic (soil sample pores and water flow velocity) and macroscopic (trench wall condition) levels, thereby evaluating the stability of the test soil sample under trench excavation and groundwater action.

[0021] (4) The device can simulate the movement of water in the soil sample at different groundwater depths by pressurizing, which leads to the collapse of the soil sample; it can test the stability of the soil layer conditions in the construction area under the action of groundwater, and quantitatively evaluate the porosity and water erosion resistance of the soil sample; at the same time, it can also approximately infer the depth at which the borehole wall may collapse, for reference by the engineering construction, so as to determine whether soil reinforcement is needed and to propose a suitable soil reinforcement method to reduce the impact of borehole wall collapse on the project progress. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of this application;

[0023] Figure 2This is a schematic diagram of the sensor-mounted platform holder in this application;

[0024] Figure 3 This is a schematic diagram of the water outlet plate in this application;

[0025] Figure 4 This is a schematic diagram of the structure of the water inlet orifice plate in this application;

[0026] Figure 5 This is a schematic diagram of the working status of this application;

[0027] Figure 6 This is a schematic diagram of the simulation method of this application;

[0028] Explanation of reference numerals in the attached figures

[0029] In the diagram: 1-Air and water inlet pipe; 2-First overflow pipe; 3-Gas cylinder; 4-Left side plate; 5-Cover plate; 6-Water inlet plate; 7-Pressure plate; 8-Rear plate; 9-First flow meter; 10-Second overflow pipe; 11-Sensor mounting platform holder; 111-Slide rail; 1101-Slide groove; 112-Mounting platform; 1121-Slider; 12-Water outlet plate; 13-Right side plate; 14-Second flow meter; 15-Third overflow pipe; 16-Pore water pressure sensor; 17-Connection port; 18-Front plate; 19-Water; 20-Quartz sand; 21-Soil sample; 22-Simulation tank. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0034] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0035] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0037] like Figure 1-5 As shown, the trench wall collapse simulation device includes:

[0038] The box has an opening at the top; the box includes a front panel 18, a rear panel 8, a left side panel 4, a right side panel 13 and a bottom panel;

[0039] Water inlet orifice plate 6;

[0040] The water outlet plate 12; the water inlet plate 6 and the water outlet plate 12 are both horizontally provided with multiple through holes. The water inlet plate 6 and the water outlet plate 12 are both set in the box body, and the space inside the box body is divided into a first area, a second area and a third area. The first area is located between the left side plate 4 and the water inlet plate 6, the second area is located between the water inlet plate 6 and the water outlet plate 12, and the third area is located between the water outlet plate 12 and the right side plate 13. Water is set in the first area; a soil sample 21 is set in the second area, and a simulation tank 22 is set in the middle of the soil sample 21; the third area is the water outlet space.

[0041] Cover plate 5; Cover plate 5 is installed above the first area and is used to close the top of the first area; Cover plate 5 serves to seal the second area, so that water can only flow out from the holes of the water inlet plate 6. This design allows the gas cylinder 3 to pressurize.

[0042] A gas inlet pipe 1 is used for water or high-pressure gas inlet; the gas inlet pipe 1 is connected to the first area; when additional pressure is required, the gas inlet pipe 1 is connected to a high-pressure gas cylinder 3 to provide a channel for pressurized gas to enter. It is used as a water inlet pipe when no external pressure is needed. The high-pressure gas cylinder 3 is used to provide additional pressure, simulating water pressure at different groundwater levels, and different specifications can be selected according to actual needs.

[0043] Multiple pore water pressure sensors 16 are used to detect pore water pressure at various locations of soil sample 21; the multiple pore water pressure sensors 16 are placed inside soil sample 21 in the second region.

[0044] A displacement sensor is used to measure the displacement of the simulated tank 22; the displacement sensor is installed inside the simulated tank 22.

[0045] like Figure 5 As shown, quartz sand 20 is placed between soil sample 21 and water inlet plate 6.

[0046] like Figure 1 and 5 As shown, a pressure plate 7 is installed to completely cover the top of the quartz sand 20. The purpose of the pressure plate 7 is to prevent water from flowing out from the top of the quartz sand 20 or the gap between the water inlet plate 6 and the soil sample 21 due to the sidewall effect, thus preventing water from flowing into the soil sample 21.

[0047] like Figure 5 As shown, the water pressure plate 7 is set at a height lower than the top of the soil sample 21, and part of the water pressure plate 7 extends into the soil sample 21.

[0048] like Figure 1 and 2 As shown, the trench wall collapse simulation device also includes a sensor mounting platform holder 11, which includes a mounting platform 112 and two slide rails 111. The two slide rails 111 are arranged opposite each other inside the front plate 18 and the rear plate 8, and are located at the setting position of the simulation trench 22. Two vertical grooves 1101 are formed on the slide rails 111. Two sliders 1121 are provided at both ends of the mounting platform 112, and the two sliders 1121 are slidably placed in the two grooves 1101 of the slide rails 111. The displacement sensor is mounted on the mounting platform 112. The frictional force between the sliders 1121 and the slide rails 111 is greater than or equal to the displacement sensor plus the weight of the mounting platform 112. In some embodiments, the mounting platform 112 can be slid up and down along the two slide rails 111 by an electric mechanism.

[0049] like Figure 1As shown, the left side plate 4 is connected to an air / water inlet pipe 1 and a first overflow pipe 2. The air / water inlet pipe 1 is used to input water or high-pressure gas. The installation height of both the air / water inlet pipe 1 and the first overflow pipe 2 is higher than the installation height of the soil sample 21. The first overflow pipe 2 is connected to an external switch valve. When no external pressure is required, it is used as an overflow outlet to maintain a constant water level in the tank. It is closed when the air inlet pipe is connected to the gas cylinder 3.

[0050] like Figure 1 As shown, a second overflow pipe 10 is provided on the rear plate 8, and a first flow meter 9 is provided on the second overflow pipe 10. The installation height of the second overflow pipe 10 is higher than the installation height of the soil sample 21.

[0051] like Figure 1 and 5 As shown, a third overflow pipe 15 is provided on the bottom side wall of the right side plate 13, and a second flow meter 14 is provided on the third overflow pipe 15.

[0052] like Figure 1 As shown, multiple connection ports 17 are provided at the bottom of the side wall of the front panel 18, and multiple pore water pressure sensors 16 are installed in the multiple connection ports 17.

[0053] In some embodiments, the front panel 18, rear panel 8, left side panel 4, right side panel 13, and bottom panel are all made of transparent glass.

[0054] like Figure 3 and 4 As shown, in some embodiments, the multiple through holes on the water inlet plate 6 and the water outlet plate 12 are arranged in a rectangular array; the diameter of the through holes on the water inlet plate 6 is smaller than the diameter of the through holes on the water outlet plate 12.

[0055] like Figure 5 and 6 As shown, the specific operation steps and methods of this application are detailed below:

[0056] 1. Sample preparation

[0057] To reduce the direct impact of water flow on soil sample 21, a layer of quartz sand 20 of a certain thickness needs to be placed on the inlet side. Simultaneously, to prevent water 19 from overflowing upwards through the quartz sand 20 layer during the experiment, a pressure plate 7 is placed on the quartz sand 20 layer to restrict the upward seepage path of water 19. To minimize the impact on experimental accuracy, the soil sample 21 should be placed as flat as possible, especially along the sides of the trench walls.

[0058] 2. Initial parameters

[0059] (1) Pore volume

[0060] Before the experiment, water was injected through the air-water inlet pipe 1 to raise the water level of the device to just level with the soil sample 21. Scale markings were made, and the water injection volume V was recorded. 注入 The pore volume can be calculated using the following formula:

[0061] V 孔隙 =V 注入 -V 左水箱 -V 右水箱 -V 槽

[0062] It is important to note that before filling the water tanks, ensure that there are no soil particles in the grooves of both the left and right tanks (first and third zones) to avoid affecting the final test results. 槽 This refers to the volume of water in the simulation tank 22.

[0063] (2) Tank wall condition

[0064] An ultrasonic ranging sensor was selected as the displacement sensor. The displacement sensor was fixed on the mounting platform 112, and the mounting platform 112 was fixed on two slide rails 111 and marked. The displacement sensor was used to measure the displacement of the simulated tank wall 22 from top to bottom, and the displacement-depth curve was plotted as the initial state of the tank wall for subsequent testing.

[0065] 3. No-pressure test

[0066] The unpressurized test is a test conducted without additional pressurization, using only water pressure to simulate shallow seepage conditions on the earth's surface.

[0067] (1) Initial front

[0068] The dye was poured into the first area, and the imaging equipment was set up at a fixed position. The changes in the front were photographed every ΔT time interval, and the time T when the front reached the simulation tank 22 was recorded. 槽 and the time T for complete seepage 终 The difference in seepage velocity can be qualitatively inferred by observing the changes in the front, and the results are relatively intuitive.

[0069] (2) Seepage parameters

[0070] After the frontal test, it is also necessary to record the height of each water head and the magnitude of the flow rate over a fixed period of time. The corresponding flow velocity can then be calculated using the following formula.

[0071]

[0072] In the formula, v is the flow velocity; Q is the flow rate; A is the cross-sectional area; Δh is the head difference; Δl is the piezometer spacing; and k is the permeability coefficient. As the experiment progresses, the porosity of the soil layer gradually increases, and the permeability coefficient also gradually increases. Therefore, flow velocities should be compared over short time periods. For comparisons of flow velocity changes over longer periods, a coefficient can be added before the formula as appropriate. Whether to add the coefficient can be determined based on changes in the tank wall condition; that is, if the tank wall changes significantly, the coefficient can be added appropriately, and if the change is small or nonexistent, the coefficient can be omitted. Note: If the flow rate is too small to be detected using a flow meter, it can be recorded by calculating the volume of water per unit time.

[0073] (3) Tank wall condition

[0074] As seepage proceeds, the condition of the tank wall needs to be monitored at fixed intervals to establish a correlation between changes in the tank wall and changes in hydraulic parameters. Specifically, this involves using an ultrasonic displacement sensor to measure the distance from the sensor to the tank wall from top to bottom (this requires moving the sensor mounting platform 112 up and down along two slide rails 111), plotting a depth-displacement curve, and comparing the curves at two different times to determine the changes in the tank wall.

[0075] 4. Repeated pressurization test

[0076] The repeated pressurization test simulates the seepage of soil samples 21 at different depths in the formation. When water is insufficient in the first region, pressure needs to be released and water re-injected; hence the name repeated pressurization. Unlike the unpressurized test, due to the applied additional pressure, water will inevitably overflow from the simulation tank 22 and flow out through the second overflow pipe 10 of the rear plate 8, bypassing or minimally bypassing the soil sample 21 on the right side of the simulation tank 22. Therefore, this test focuses only on the seepage of the soil sample 21 on the left side. The methods for obtaining seepage parameters and tank wall changes are the same as described above.

[0077] 5. Final parameters

[0078] The purpose of obtaining the final parameters is to compare them with the initial parameters, characterize the changes in relevant parameters before and after the experiment, and illustrate the impact of seepage on the soil layer and trench walls. The testing methods for relevant parameters are the same as described above.

[0079] 6. Results Compilation

[0080] By organizing the data obtained during the experiment, different data results can be obtained.

[0081] By comparing the changes in the front at different time points during the same test, we can determine the difference in flow velocity at different locations at the same moment. Comparing two frontal experiments reveals the difference in flow velocity at the same location between the two experiments.

[0082] By analyzing flow-time data, we can deduce the overall changes in flow velocity and draw macroscopic conclusions.

[0083] Processing the velocity-time data allows us to determine the specific velocity changes at different times and locations. By comparing the differences between the data, we can qualitatively determine the porosity changes in soil sample 21. The results of this data can be corroborated with the flow-time results.

[0084] The displacement of the tank wall is one of the most important data points in the experiment. By processing this data, we can determine the changes in tank wall displacement at different pressures and times. Combining this with the previously processed data, we can initially establish the relationship between flow velocity, displacement, and porosity, providing a basis for drawing conclusions.

[0085] 7. Conclusion

[0086] The processed experimental data were analyzed, and relevant literature was consulted to determine the mechanism by which seepage affects the stability of the trench wall. This mechanism was used to evaluate the stability of the measured soil sample 21, i.e., under what pressure is the trench wall most likely to collapse. Simultaneously, this device can also be used to evaluate the effectiveness of trench wall reinforcement materials.

[0087] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for simulating tank wall collapse, characterized in that, include: The box has an opening at the top; the box includes a front panel, a rear panel, a left side panel, a right side panel, and a bottom panel; Inlet orifice plate; Water outlet plate; Both the inlet and outlet perforations have multiple horizontal through holes. The inlet and outlet perforations are located inside the tank, dividing the internal space into three zones: the first zone is between the left side plate and the inlet perforation plate, the second zone is between the inlet and outlet perforations plate, and the third zone is between the outlet perforation plate and the right side plate. Water is placed in the first zone; a soil sample is placed in the second zone, with a simulation tank in the center of the soil sample; the third zone is the water outlet space. Cover plate; The cover plate is installed above the first area and is used to close the top of the first area; A gas inlet pipe for water or high-pressure gas intake; the gas inlet pipe is connected to the first area. Multiple pore water pressure sensors; multiple pore water pressure sensors are placed inside the soil sample in the second region; A displacement sensor is used for simulating tank displacement measurement; the displacement sensor is installed inside the simulated tank. The sensor mounting platform holder includes a mounting platform and two slide rails. The two slide rails are arranged opposite each other on the inner sides of the front and rear plates and are located at the position of the simulation slot. Vertical grooves are provided on the slide rails. Sliders are provided at both ends of the mounting platform and are slidably placed in the grooves of the slide rails. The displacement sensor is mounted on the mounting platform. The friction between the slider and the slide rail is greater than or equal to the displacement sensor plus the weight of the mounting platform.

2. The trench wall collapse simulation device according to claim 1, characterized in that, Quartz sand was placed between the soil sample and the inlet plate.

3. The trench wall collapse simulation device according to claim 2, characterized in that, A pressure plate is installed to completely cover the top of the quartz sand.

4. The trench wall collapse simulation device according to claim 3, characterized in that, The pressure plate is set at a height lower than the top of the soil sample, with part of the pressure plate extending into the soil sample.

5. The trench wall collapse simulation device according to claim 1, characterized in that, The left side plate is connected to an air inlet pipe and a first overflow pipe. The air inlet pipe is used to input water or high-pressure gas. The air inlet pipe and the first overflow pipe are both installed at a height higher than the soil sample.

6. The trench wall collapse simulation device according to claim 1, characterized in that, A second overflow pipe is installed on the rear plate, and a first flow meter is installed on the second overflow pipe. The installation height of the second overflow pipe is higher than the installation height of the soil sample.

7. The trench wall collapse simulation device according to claim 1, characterized in that, A third overflow pipe is installed on the bottom of the side wall of the right side plate, and a second flow meter is installed on the third overflow pipe.

8. The trench wall collapse simulation device according to claim 1, characterized in that, Multiple connection ports are provided at the bottom of the side wall of the front panel, and multiple pore water pressure sensors are installed in multiple connection ports.

9. The trench wall collapse simulation device according to claim 1, characterized in that, The front panel, rear panel, left side panel, right side panel, and bottom panel are all made of transparent material.

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