Soil body internal settlement and soil pressure monitoring device and method for model test

Abstract

The invention provides a soil internal settlement and soil pressure monitoring device and method for a model test, and the device comprises a bottom observation box which is internally provided with a bottom stay wire displacement meter; an earth surface observation box, wherein an earth surface stay wire displacement meter is arranged in the earth surface observation box; the settlement plate assembly is pre-buried in a to-be-measured settlement position and a to-be-measured pressure position in the soil body; the telescopic corrugated hose comprises an upper section and a lower section, the stay wire of the stay wire displacement meter and the stay wire of the bottom stay wire displacement meter are arranged in the upper section and the lower section of the telescopic corrugated hose in a penetrating manner, and the earth surface stay wire displacement meter is connected to the lower surface and the upper surface of the settlement plate assembly respectively. According to the invention, the vertical settlement, the horizontal soil pressure and the vertical soil pressure of the soil body can be measured at the same time, the integrated monitoring of multiple parameters is realized, and the monitoring comprehensiveness is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of geotechnical tests, and particularly relates to a device and method for monitoring soil internal settlement and earth pressure in model tests. Background Art

[0002] At present, significant progress has been made in the field of soil settlement monitoring technology for in-situ soil internal monitoring. Existing technologies mainly achieve soil settlement monitoring through physical devices and automated systems, providing important data support for engineering safety assessment. However, these technologies are mainly oriented towards large-scale engineering site monitoring and all use large-size and large-rigidity settlement rods or similar devices. The disturbance problem caused by such rigid devices buried in the soil can be ignored at the engineering scale, but it will have an undeniable impact in small-scale model tests with high precision requirements and small sizes. There are obvious limitations in the application of small-scale model tests with high precision requirements and precise sizes.

[0003] Chinese invention patent CN 114739359 A needs to set an outer casing and an inner settlement pipe when monitoring soil internal settlement, and then measure the settlement displacement through a level connected to the top of the inner settlement pipe. The outer casing has a large rigidity, which will significantly interfere with the response of the soil itself when applied to model tests. At the same time, the friction between the inner settlement pipe and the outer casing will also cause errors in the measurement results.

[0004] Chinese invention patent CN 115248027 A sets a settlement reference rod when measuring settlement. In model tests, this settlement reference rod will affect the response of the model soil and interfere with the test results.

[0005] Chinese invention patent CN 114739359 A first needs to anchor the settlement measurement mechanism on the soil surface when measuring soil internal settlement. In model tests, there is often no space and implementation conditions for anchoring on the soil surface, otherwise it will cause great interference to the research of the model test itself. Secondly, it is necessary to set exploration wells in the soil. In the research of model tests, setting exploration wells will cause huge interference to the observation and development of the test itself.

[0006] In addition, the current soil internal settlement monitoring devices have relatively single functions. In small-scale model tests, it is often necessary to monitor multiple physical quantities (such as earth pressure and settlement) simultaneously. Existing devices need to arrange multiple sets of sensor systems, which are complex to operate, prone to introducing interference, and reduce the test efficiency.

[0007] Generally speaking, although the existing technologies can effectively solve the problem of soil settlement monitoring in large-scale projects, they still need to be improved in precise small-scale model tests. There is an urgent need to develop monitoring devices suitable for miniaturization and low interference to better meet the requirements of experimental accuracy and uniformity. Summary of the Invention

[0008] The first purpose of the present invention is to solve the problem that in scaled model tests, large-sized and high-rigidity settlement rods or similar devices will interfere with the response of the soil itself, and the friction between the devices will also introduce measurement errors. In addition, in scaled model tests, due to the small size, the integration requirements for sensors are high, and the arrangement of multiple sensors will affect and interfere with the test itself. Therefore, a new type of miniaturized, low-interference soil internal settlement and soil pressure monitoring device for model tests is provided.

[0009] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions: A soil internal settlement and soil pressure monitoring device for model testing, comprising: A bottom observation box, wherein a bottom wire displacement meter is provided in the bottom observation box; A surface observation box, wherein a surface wire displacement meter is provided in the surface observation box; A settlement plate assembly, wherein the settlement plate assembly is pre-buried in the soil at a location where settlement and pressure to be measured are to be measured; The telescopic corrugated hose comprises an upper section and a lower section, wherein the pull wire of the pull wire displacement meter is passed through the upper and lower sections of the telescopic corrugated hose, and the pull wire of the bottom pull wire displacement meter and the surface pull wire displacement meter are respectively connected to the lower surface and the upper surface of the settlement plate assembly.

[0010] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions: As a preferred technical solution of the present invention: the settlement plate assembly comprises: a horizontal settlement plate and a vertical pressure plate, wherein the horizontal settlement plate and the vertical pressure plate form a cross-shaped settlement plate assembly; The horizontal settlement plate is provided with a horizontally arranged vertical earth pressure sensor, and the vertical pressure plate is provided with a vertically arranged horizontal earth pressure sensor.

[0011] As a preferred technical solution of the present invention: the vertical earth pressure sensor is a thin film earth pressure sensor, which is pasted to the surface of the horizontal settlement plate.

[0012] As a preferred technical solution of the present invention: the horizontal earth pressure sensor is a thin film earth pressure sensor, which is pasted to the surface of the vertical pressure plate.

[0013] As a preferred technical solution of the present invention: the upper end of the upper telescopic corrugated hose is connected to the bottom of the surface observation box, and the lower end of the upper telescopic corrugated hose is connected to the upper surface of the sedimentation plate assembly.

[0014] As a preferred technical solution of the present invention: the lower end of the lower telescopic corrugated hose is connected to the top of the bottom observation box, and the upper end of the lower telescopic corrugated hose is connected to the lower surface of the settlement plate assembly.

[0015] As a preferred technical solution of the present invention: the telescopic corrugated hose is made of a polyurethane steel wire hose, and the hose is composed of a bent steel wire coil as the skeleton and a polyurethane film.

[0016] As a preferred technical solution of the present invention: the bottom observation box and the surface observation box are both provided with connection holes to dock with the telescopic corrugated hose.

[0017] As a preferred technical solution of the present invention: the bottom observation box and the surface observation box are both provided with wiring holes to lead out the data lines of the pull wire displacement meter.

[0018] Another object of the present invention is to provide a method for monitoring soil internal settlement and soil pressure for model tests.

[0019] To this end, the above object of the present invention is achieved by the following technical solutions: A method for monitoring soil internal settlement and soil pressure for model tests, the method is based on the monitoring device as described above, and includes the following steps: S1. Fix the bottom pull wire displacement meter inside the bottom observation box, and fix the bottom observation box at the projection position of the bottom of the model box corresponding to the internal settlement measurement point of the soil to be measured; S2. Cut the lower telescopic corrugated hose with a corresponding length according to the depth of the internal settlement measurement point of the soil to be measured, and connect its end to the top opening of the bottom observation box; S3. Lead out the measurement pull wire of the bottom pull wire displacement meter through the internal cavity of the lower telescopic corrugated hose, connect it to the lower surface of the horizontal settlement plate of the settlement plate assembly, and connect the top end of the lower telescopic corrugated hose to the lower surface of the horizontal settlement plate of the settlement plate assembly; S4. Paste thin film soil pressure sensors on the horizontal settlement plate and the vertical pressure plate of the settlement plate assembly respectively, and lead the wires of the thin film soil pressure sensors into the bottom observation box through the telescopic corrugated hose; S5. Temporarily fix the settlement plate assembly through a temporary support, and perform filling and tamping operations according to the requirements of the model test; S6. When the filling reaches the position of the settlement plate assembly, remove the temporary support; S7. Fix the surface pull wire displacement meter inside the surface observation box, and fix the surface observation box downward at the cross beam or the top of the model box structure at the projection position of the top of the model box corresponding to the internal settlement measurement point of the soil to be measured; S8. Cut another upper telescopic corrugated hose with a corresponding length according to the soil burial depth of the internal settlement measurement point of the soil to be measured, and connect its end to the top opening of the surface observation box; S9, lead the measuring wire of the surface wire displacement meter through the inner cavity of the upper telescopic corrugated hose, connect it to the upper surface of the horizontal settlement plate of the settlement plate assembly, and connect the top end of the upper telescopic corrugated hose to the upper surface of the horizontal settlement plate of the settlement plate assembly; S10, continue to perform soil filling and tamping operations according to the model test requirements until the designed soil height is reached; S11, read and debug the data of the wire displacement meter and the earth pressure sensor, measure the initial value, and synchronize data acquisition to ensure that the sensors start and end data acquisition at the same time to avoid errors caused by time difference; S12. Conduct experiments, collect and record sensor readings.

[0020] The present invention provides a soil internal settlement and soil pressure monitoring device and method for model testing. Firstly, the size and stiffness of the settlement monitoring device were considered to ensure its applicability in scaled model tests. To address this problem, a settlement plate assembly was designed. The assembly can be pre-buried in the soil and deform together with the soil, thereby reducing interference with the soil.

[0021] Secondly, the data transmission of the settlement plate assembly adopts a telescopic corrugated hose. Unlike traditional exploration wells or rigid settlement rods, the hose deforms together with the soil and causes little disturbance to the soil.

[0022] Thirdly, the monitoring accuracy issue was taken into consideration, and a pull-wire displacement meter with extremely high measurement accuracy was used as the data acquisition instrument, combined with a wired signal transmission and connection system to ensure the accuracy of the monitoring data.

[0023] Finally, vertical and horizontal earth pressure sensors are integrated on the settlement plate assembly to realize the integrated monitoring of soil vertical settlement, horizontal earth pressure and vertical earth pressure.

[0024] Specifically, the present invention has the following beneficial effects: (1) The settlement plate can deform together with the soil, causing little disturbance to the soil. It can also accurately reflect the vertical settlement and horizontal earth pressure of the soil, thus realizing integrated monitoring.

[0025] (2) Use a high-precision pull-wire displacement meter to measure the settlement value to improve the settlement monitoring accuracy. At the same time, the sensor wiring is led out through the internal cavity of the telescopic corrugated hose to the observation box to provide stable signal transmission and ensure the reliability of data collection.

[0026] (3) The telescopic corrugated hose can freely expand and contract with the soil, reducing disturbance to the soil. At the same time, it protects the wire of the wire displacement meter from almost any friction interference, ensuring the accuracy of the measurement data. It is especially suitable for scenarios with high requirements for soil disturbance, such as model tests.

[0027] (4) The fixed positions and structural designs of the bottom observation box and the surface observation box provide a stable storage position for the wire-pull displacement meter, which is not affected by soil deformation, ensuring the stability of the measurement data.

[0028] (5) One wire-pull displacement meter is installed at the bottom and one at the surface for tension monitoring to improve the reliability of the data. The measurement data of the two wire-pull displacement meters can be averaged to obtain a result close to the true value. Even if a single data fails, an effective data can still be retained.

[0029] The present invention can simultaneously measure the vertical settlement, horizontal soil pressure, and vertical soil pressure of the soil mass, realizing the integrated monitoring of multiple parameters and improving the comprehensiveness of the monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the layout diagram of a device for monitoring the internal settlement and soil pressure of the soil mass used in the model test provided by the present invention.

[0031] Figure 2 It is the structural diagram of the bottom observation box.

[0032] Figure 3 It is the structural diagram of the telescopic corrugated hose.

[0033] Figure 4 It is the structural diagram of the settlement plate assembly.

[0034] In the above figures: 1 - bottom observation box; 2 - bottom wire-pull displacement meter; 3 - telescopic corrugated hose; 4 - settlement plate assembly; 5 - surface observation box; 6 - surface wire-pull displacement meter; 11 - reserved wiring hole of the observation box; 12 - reserved top connection hole of the observation box; 21 - wire drawn out from the wire-pull displacement meter; 31 - thin film on the surface of the corrugated hose; 32 - steel ring inside the corrugated hose; 41 - horizontal settlement plate; 42 - vertical pressure plate; 43 - vertical soil pressure sensor; 44 - horizontal soil pressure sensor. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

[0036] As Figure 1 shown, a device for monitoring the internal settlement and soil pressure of the soil mass used in the model test includes: A bottom observation box 1, fixed at the bottom of the model test box, and a bottom wire-pull displacement meter 2 is fixed inside it; A surface observation box 5, fixed on the top crossbeam or similar fixed structure of the model test box, and a surface wire-pull displacement meter 6 is fixed inside it; The bottom observation box 1 and the surface observation box 5 are respectively fixed at the bottom of the model test box and on the ground surface, not affected by soil deformation, and provide stable storage positions for the bottom wire displacement meter 2 and the surface wire displacement meter 6.

[0037] A hole corresponding to the size of the telescopic corrugated hose 3 is reserved at the top of the bottom observation box 1 / surface observation box 5 (as Figure 2 shown, the top connection hole 12 of the observation box is reserved. Similarly, the surface observation box 5 is arranged in the same way), for connecting the telescopic corrugated hose 3. The lead wire 21 of the wire displacement meter passes through the top connection hole 12 of the observation box; a small hole corresponding to the data lines of the bottom wire displacement meter 2 and the surface wire displacement meter 6 is reserved at the bottom (as Figure 2 shown, the wiring hole 11 of the observation box is reserved. Similarly, the surface observation box 5 is arranged in the same way), for leading out the data lines of the wire displacement meter, and the pore is sealed.

[0038] The telescopic corrugated hose 3 includes two independent upper and lower sections: One end of the lower half is connected to the top of the bottom observation box 1, and the other end is connected to the lower surface of the settlement plate assembly 4; One end of the upper half is connected to the bottom of the surface observation box 5, and the other end is connected to the upper surface of the settlement plate assembly 4.

[0039] The upper and lower ends of the telescopic corrugated hose 3 are respectively connected to the bottom observation box 1 / surface observation box 5 and the settlement plate assembly 4 to prevent soil from entering the interior.

[0040] As Figure 3 shown, the telescopic corrugated hose 3 is made of a polyurethane steel wire hose, which is a hose composed of a bent steel wire coil (the inner steel ring 32 of the corrugated hose) as the skeleton and a polyurethane film (the surface film 31 of the corrugated hose), and can freely stretch and bend and resist soil pressure without being flattened.

[0041] The settlement plate assembly 4 is buried inside the soil at the position to be measured for settlement and pressure. As Figure 4 shown, it includes: A horizontal settlement plate 41, which deforms together with the soil and reflects the vertical settlement, and at the same time monitors the vertical soil pressure; A vertical pressure plate 42, which is fixedly arranged vertically in the middle of the horizontal settlement plate 41 and is used to monitor the horizontal soil pressure; On the surface of the horizontal settlement plate 41, there are vertically arranged vertical soil pressure sensors 43 horizontally. On the surface of the vertical pressure plate 42, there are horizontally arranged horizontal soil pressure sensors 44 vertically. The vertical soil pressure sensors 43 and the horizontal soil pressure sensors 44 are thin-film soil pressure sensors, which are respectively pasted on the surface of the horizontal settlement plate and the surface of the vertical pressure plate and are used to measure the vertical and horizontal soil pressures; The settlement plate assembly 4 is used to deform together with the soil at the settlement position inside the soil to be measured and reflect the settlement situation of the soil at that place.

[0042] The upper and lower surfaces of the settlement plate assembly 4 are respectively connected to the surface wire displacement meter 6 and the bottom wire displacement meter 2 to simultaneously provide the measurement data of the two wire displacement meters.

[0043] The upper and lower surfaces of the settlement plate assembly 4 are connected to the telescopic corrugated hose 3. The telescopic corrugated hose 3 can freely expand and contract and deform with the soil mass without interfering with the co-settlement of the settlement plate assembly 4 with the soil mass.

[0044] The settlement plate assembly 4 can simultaneously measure three physical quantities: the vertical settlement of the soil mass, the horizontal soil pressure, and the vertical soil pressure.

[0045] The wire of the bottom wire displacement meter 2 is connected to the lower surface of the horizontal settlement plate 41 through the lower telescopic corrugated hose 3, and the wire of the surface wire displacement meter 6 is connected to the upper surface of the horizontal settlement plate through the upper telescopic corrugated hose; the wires of the bottom wire displacement meter 2 and the surface wire displacement meter 6 are stored in the internal cavity of the telescopic corrugated hose 3, so that the movement of the wires is not interfered by factors such as soil friction.

[0046] The wiring of the thin-film soil pressure sensors (vertical soil pressure sensor 43, horizontal soil pressure sensor 44) is led out through the internal cavity of the telescopic corrugated hose 3 to the surface observation box 5 and then connected to the acquisition terminal. Among them, the wire of the bottom wire displacement meter 2 is connected to the lower surface of the settlement plate assembly 4 through the internal cavity of the telescopic corrugated hose 3, and the wire of the surface wire displacement meter 6 is connected to the upper surface of the settlement plate assembly 4 through the internal cavity of another section of the telescopic corrugated hose 3.

[0047] A method for monitoring the internal settlement and soil pressure of soil mass in model tests, based on the above monitoring device, and specifically includes the following steps: S1. Before the start of the model test, fix the bottom wire displacement meter 2 inside the bottom observation box 1, fix the bottom observation box 1 at the projection position of the bottom of the model box corresponding to the internal settlement measurement point of the soil mass to be measured, and lead out the data line of the bottom wire displacement meter 2 through the reserved hole; S2. Cut the telescopic corrugated hose 3 with a corresponding length according to the depth of the internal settlement measurement point of the soil mass to be measured, and connect its end to the top opening of the bottom observation box 1; S3. Lead out the measurement wire of the bottom wire displacement meter 2 through the internal cavity of the lower telescopic corrugated hose and connect it to the lower surface of the horizontal settlement plate 41, and connect the top of the telescopic corrugated hose 3 to the lower surface of the horizontal settlement plate 41; S4. Paste the thin-film soil pressure sensors (vertical soil pressure sensor 43 and horizontal soil pressure sensor 44), and lead the wires of the soil pressure sensors into the bottom observation box through the telescopic corrugated hose and lead them out through the reserved hole; S5. Temporarily fix the settlement plate assembly 4 by means of a temporary support or the like, and perform operations such as filling and tamping in accordance with the requirements of the model test; S6. When the filling reaches the position of the settlement plate assembly 4, remove the temporary support; S7. Fix the surface wire displacement meter 6 inside the surface observation box 5, fix the surface observation box 5 downward at the crossbeam at the projection position of the top of the model box corresponding to the settlement measurement point inside the soil to be measured or at the top of the model box structure, and lead out the data line of the surface wire displacement meter 6 through the reserved hole; S8. According to the buried depth of the soil body at the settlement measurement point inside the soil to be measured, cut another section of the telescopic corrugated hose 3 with a corresponding length, and connect its end to the top opening of the surface observation box 5; S9. Lead out the measuring wire of the surface wire displacement meter 6 through the inner cavity of the telescopic corrugated hose 3, connect it to the upper surface of the horizontal settlement plate 41, and connect the top end of the telescopic corrugated hose 3 to the upper surface of the horizontal settlement plate 41; S10. Continue to perform operations such as filling and tamping in accordance with the requirements of the model test until the designed soil height is reached; S11. Read and debug the data of the wire displacement meter and the earth pressure sensor, measure the initial value, and synchronize the data acquisition to ensure that all sensors start and end the data acquisition simultaneously to avoid errors caused by time differences; S12. Conduct the test, collect and record the sensor readings.

[0048] The above specific embodiments are used to explain the present invention, and are only the preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and scope of the protection of the claims of the present invention fall within the protection scope of the present invention.

Claims

1. An internal soil settlement and earth pressure monitoring device for model tests, characterized in that: include: A bottom observation box, wherein a bottom wire displacement meter is provided in the bottom observation box; A surface observation box, wherein a surface wire displacement meter is provided in the surface observation box; A settlement plate assembly, wherein the settlement plate assembly is pre-buried in the soil at a location where settlement and pressure to be measured are to be measured; The telescopic corrugated hose comprises an upper section and a lower section, wherein the pull wire of the pull wire displacement meter is passed through the upper and lower sections of the telescopic corrugated hose, and the pull wire of the bottom pull wire displacement meter and the surface pull wire displacement meter are respectively connected to the lower surface and the upper surface of the settlement plate assembly.

2. The monitoring device according to claim 1, characterized in that: The settlement plate assembly comprises: a horizontal settlement plate and a vertical pressure plate, wherein the horizontal settlement plate and the vertical pressure plate form a cross-shaped settlement plate assembly; The horizontal settlement plate is provided with a horizontally arranged vertical earth pressure sensor, and the vertical pressure plate is provided with a vertically arranged horizontal earth pressure sensor.

3. The monitoring device according to claim 2, characterized in that: The vertical earth pressure sensor is a thin film earth pressure sensor, which is adhered to the surface of the horizontal settlement plate.

4. The monitoring device according to claim 2, characterized in that: The horizontal earth pressure sensor is a thin film earth pressure sensor, which is adhered to the surface of the vertical pressure plate.

5. The monitoring device according to claim 1, characterized in that: The upper end of the upper telescopic corrugated hose is connected to the bottom of the surface observation box, and the lower end of the upper telescopic corrugated hose is connected to the upper surface of the settlement plate assembly.

6. The monitoring device according to claim 1, wherein: The lower end of the lower telescopic corrugated hose is connected to the top of the bottom observation box, and the upper end of the lower telescopic corrugated hose is connected to the lower surface of the settling plate assembly.

7. The monitoring device according to claim 1 or 5 or 6, characterized in that: The telescopic corrugated hose is made of polyurethane steel wire hose, with a bent steel wire roll as the skeleton and a polyurethane film as the hose.

8. The monitoring device according to claim 1, wherein: The bottom observation box and the surface observation box are both provided with connection holes for connecting with the telescopic corrugated hose.

9. The monitoring device according to claim 1, wherein: The bottom observation box and the surface observation box are both provided with wiring holes to lead out the data lines of the wire displacement meter.

10. A method for monitoring internal settlement and earth pressure of soil mass in model tests, characterized in that: The method is based on the monitoring device according to any one of claims 1 to 9, and comprises the following steps: S1. Fix the bottom wire displacement meter inside the bottom observation box, and fix the bottom observation box to the bottom projection position of the model box corresponding to the settlement measuring point inside the soil body to be measured; S2. According to the depth of the settlement measuring point inside the soil body to be measured, cut the corresponding length of the lower section of the telescopic corrugated hose and connect its end to the top opening of the bottom observation box; S3, lead the measuring wire of the bottom wire displacement meter through the inner cavity of the lower telescopic corrugated hose, connect it to the lower surface of the horizontal settlement plate of the settlement plate assembly, and connect the top end of the lower telescopic corrugated hose to the lower surface of the horizontal settlement plate of the settlement plate assembly; S4, attaching thin film soil pressure sensors to the horizontal settlement plate and the vertical pressure plate of the settlement plate assembly respectively, and introducing the wires of the thin film soil pressure sensors to the bottom observation box through the telescopic corrugated hose; S5. Temporarily fix the settlement plate assembly by means of temporary brackets and perform soil filling and compaction operations according to the model test requirements; S6. When the filling reaches the position of the settlement plate assembly, the temporary support is removed; S7, fix the surface wire displacement meter inside the surface observation box, and fix the surface observation box downward to the crossbeam or the top of the model box structure at the projection position of the top of the model box corresponding to the settlement measuring point inside the soil body to be measured; S8. According to the buried depth of the internal settlement measuring point of the soil body to be measured, cut another section of the upper telescopic corrugated hose of corresponding length, and connect the end thereof to the top opening of the surface observation box; S9. Lead out the measuring wire of the surface guy wire displacement meter through the inner cavity of the upper telescopic corrugated hose, and connect it to the upper surface of the horizontal settlement plate of the settlement plate assembly. Connect the top of the upper telescopic corrugated hose to the upper surface of the horizontal settlement plate of the settlement plate assembly; S10. Continue to carry out the soil filling and tamping operation according to the requirements of the model test until the designed soil height is reached; S11. Read and debug the data of the wire displacement meter and the soil pressure sensor, measure the initial value, and synchronize the data acquisition to ensure that all sensors start and end the data acquisition at the same time to avoid errors caused by time differences; S12. Conduct the test, collect and record the sensor readings.

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