Simulation monitoring and method for granite residual soil slope in rainfall process under simulated earthquake action

Abstract

The invention discloses simulation monitoring and method for a granite residual soil slope in a rainfall process under the action of simulated earthquake. The simulation monitoring system mainly comprises a model box, a rainfall module, an earthquake module and a monitoring module, a water collecting tank is arranged at the bottom of the model box, a drainage hole is formed in the left side wall of the water collecting tank and connected with a drainage pipeline, and the drainage pipeline is connected with a drainage box; a water conveying pipeline is arranged at the top of the model box; an intelligent flow control valve is arranged on the water conveying pipeline; the top of the model box is provided with a counter-force cover plate and a force transmission penetration coupler, and a slope top loading system is arranged between the counter-force cover plate and the force transmission penetration coupler; the earthquake module comprises a vibration motor and a base, the vibration motor is fixed at the bottom of the water collecting tank, and the fixed base is arranged below the vibration motor; the monitoring module comprises a pore water pressure gauge, a soil pressure box, a soil engineering data acquisition instrument and a high-speed camera, the soil pressure box is arranged between the side slope front side baffle and the inner side wall of the model box, and the soil engineering data acquisition instrument acquires data and transmits the data to the computer operation terminal. The device can be used for simulating slope model test research under the action of downhill top load and earthquake under the rainfall condition, simulating the thickening rainfall infiltration function and analyzing external influence factors of slope instability failure, and the reliability and authenticity of slope stability research are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering, and in particular to a model test device for simulating the instability of a granite residual soil slope under an earthquake. Background Art

[0002] Granite is widely distributed in my country, especially in the southeast. Residual soil on the weathering crust of granite plays an important role in engineering construction. However, differences in climatic and environmental conditions in different places lead to different degrees of weathering. The higher the temperature and rainfall, the stronger the weathering. Therefore, in the southeastern provinces of my country, granite residual soil is common in mountains, hills and denuded peneplains, becoming an important foundation and geological environment medium for engineering construction. Rainfall is one of the main factors that induce slope instability, especially in the south. Increased pore water pressure and increased volumetric water content are one of the main causes of slope sliding failure under rainfall conditions. The south is often affected by long-lasting, high-intensity and widely distributed heavy rains, which makes rainfall closely related to disasters such as landslides and mud-rock flows. Establishing a correlation with rainfall and gaining a deep understanding of its development mechanism are the keys to disaster prevention and mitigation and ensuring safety. Landslide accidents occur frequently, and society is paying increasing attention to slope stability issues. Slope support measures are divided into two categories: reducing the sliding force of landslides and increasing support structures. It is expected to provide useful information for engineering safety.

[0003] Earthquakes will increase the pore pressure of the soil. As the inertial force of the earthquake and the excess pore water pressure after the earthquake grow and accumulate rapidly, the strength of the soil will be reduced, which will affect the stability of the slope and increase the risk of slope instability. Earthquake-induced landslides are very destructive. Under the action of earthquake loads, the slope is prone to thixotropy, liquefaction, shear failure and other phenomena, thereby inducing landslides. Many large landslides are caused by earthquakes. Therefore, conducting engineering geological research on earthquake-induced landslides, judging the stability of slopes, and assessing the risk of slope instability are of great importance to ensuring my country's economic development and the safety of people's lives.

[0004] Existing research mainly focuses on the stability of slopes under self-weight conditions, without considering loads such as large-scale buildings. In addition, model tests are generally only conducted on rock slopes under certain extreme conditions. Their functions are relatively single and they cannot simulate the influence of multiple factors at the same time. Moreover, simulation of only one external factor cannot meet the needs of current simulation tests. There are even fewer studies on the simultaneous influence of three factors, namely heavy rain, slope top overload and earthquake. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a model test device for simulating the instability of granite residual soil slope under earthquake action.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A model test device for simulating the instability of a granite residual soil slope under earthquake action, mainly comprising a model box, a rainfall module, a seismic module and a monitoring module; a water collecting trough is provided at the bottom of the model box, a drainage hole is provided on the left wall of the water collecting trough, the drainage hole is connected to a drainage pipe, and the drainage pipe is connected to a drainage box; a water delivery pipeline, a force transmission and penetration coupler and a reaction cover are provided on the top of the model box, an intelligent flow control valve is provided on the water delivery pipeline, and a slope top loading system is provided on the reaction cover and the force transmission and penetration coupler; the seismic module comprises a vibration motor and a base, the vibration motor is fixed at the bottom of the water collecting trough, and a fixed base is provided under the vibration motor; the monitoring module comprises a pore water pressure gauge, an earth pressure box, a geotechnical data acquisition instrument and a high-speed camera, the earth pressure box is arranged between the front baffle of the slope and the inner wall of the model box, and the geotechnical data acquisition instrument collects data and transmits it to a computer operation terminal;

[0008] The model box is transparent acrylic; the slope top loading system includes an air bag; the force transmission and penetration coupler is a rectangular tube composed of a number of loading and force transmission frames spliced ​​together by tongue-and-groove seams; the two sides of the rectangular tube are open, and the bottom of the rectangular tube is spliced ​​to form a plurality of strip gaps, and the loading and force transmission frames can move vertically along the tongue-and-groove seams; the air bag is laid flat between the reaction cover plate and the force transmission and penetration coupler; a reserved hole is opened on any side panel of the model box; the air bag is connected to an air pump after passing through the reserved hole in the side panel of the model box through an air pipe; a pressure gauge is provided on the air pipe; a water collecting trough is provided at the bottom of the model box; the water collecting trough is fixed to the model box through a card slot; the bottom of the model box is provided with drainage circular holes with equal spacing; the drainage circular holes are blocked by a piston, the upper end of the piston is flush with the upper end of the bottom of the model box, and the lower end of the piston extends to the drainage trough;

[0009] Preferably, a drainage hole is provided on the left side wall of the drainage groove, and the drainage hole is connected to the drainage box outside the model box through a drainage pipe;

[0010] Preferably, the front, rear and left side walls of the model box are provided with drainage holes, and the left side of the right side wall is provided with a baffle;

[0011] Preferably, the outer wall of the model box is painted with a coordinate grid;

[0012] The rainfall module includes: a water supply tank, a booster pump, an intelligent flow control valve, a water delivery pipeline, and a sprinkler head; the sprinkler head is fixed on the top of the model box;

[0013] Preferably, the water delivery pipeline is connected to the spray head;

[0014] Preferably, the intelligent flow control valve is arranged on the water delivery pipeline; the intelligent flow control valve is electrically connected to the operation terminal, and the operation terminal is a computer;

[0015] The seismic module comprises a vibration motor and a base; the vibration motor is fixed at the bottom of the water collection tank;

[0016] Preferably, the vibration motor is fixed to the top of the base by bolts;

[0017] Preferably, the four corners of the base are fixed to the ground;

[0018] The vibration motor includes a No. 1 vibration motor, a No. 2 vibration motor, and a No. 3 vibration motor; the vibration motor is a bidirectional vibration motor; the No. 2 vibration motor is fixed in the middle of the bottom of the water collection tank, the No. 1 vibration motor is fixed on the left side of the No. 2 vibration motor, and the No. 3 vibration motor is fixed on the right side of the No. 2 vibration motor, and the No. 1 vibration motor and the No. 3 vibration motor are at the same distance from the No. 2 vibration motor;

[0019] The soil pressure boxes are arranged at equal intervals between the baffle and the inner side wall of the model box;

[0020] Preferably, the pore water pressure gauges are connected in series through polyester sheathed sensing optical fibers and arranged in layers inside the slope;

[0021] Preferably, the geotechnical data collector is connected to a computer operation terminal via a USB interface and transmits data;

[0023] Preferably, the high-speed camera is arranged in the middle of the front side of the model box.

[0024] Compared with the prior art, the present invention also has the following advantages:

[0025] The present invention can efficiently simulate external conditions such as rainfall, slope top pressure and earthquake on rock and soil slopes, and record and transmit data through a geotechnical data acquisition instrument, with simple operation and strong practicality.

[0026] The rainfall module and the earthquake module of the present invention are independent of each other and do not interfere with each other. According to test needs, slope model test research under rainfall seepage, earthquake vibration or mutual coupling can be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a model test device for simulating the instability of a granite residual soil slope under an earthquake provided by the present invention;

[0028] Figure 2 It is a structural schematic diagram of a rainfall module in a model test device for simulating the instability of a granite residual soil slope under an earthquake provided by the present invention;

[0029] Among them, 1. model box; 2. water collection tank; 3. piston; 4. drainage pipe; 5. drainage box; 6. baffle; 7. sprinkler head; 8. water supply pipe; 9. No. 1 vibration motor; 10. No. 2 vibration motor; 11. No. 3 vibration motor; 12. base; 13. pore water pressure gauge; 14. soil pressure box; 15. optical fiber; 16. high-speed camera; 17. water supply tank; 18. booster pump; 19. intelligent flow control valve; 20. computer 21. reaction cover plate; 22. force transmission penetration coupler; 23. air bag; 24. air pipe; 25. barometer; 26. air pump. Specific implementation method:

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear and explicit, the present invention is further described below with reference to the accompanying drawings and embodiments.

[0031] Example:

[0032] Please refer to Figure 1 , a model test device for simulating the instability of granite residual soil slope under earthquake action, including a model box, a rainfall module, an earthquake module and a monitoring module;

[0033] The model box 1 is an acrylic transparent box, and drainage holes are arranged on the front, rear and left walls of the model box 1 to simulate the situation that the natural slope drains water in all directions during rainfall; a reaction cover plate 21 is arranged on the top of the model box 1, and a force transmission and penetration coupler 22 is placed on the top of the slope. A rainfall infiltration simulation system is crossed in the internal space of the force transmission and penetration coupler 22, and a slope top loading system is installed between the force transmission and penetration coupler 22 and the reaction cover plate 21; a baffle plate 6 is arranged on the left side of the right side wall of the model box 1, and the right side wall of the model box 1 and the baffle plate 6 jointly fix the earth pressure box 14; the bottom of the model box 1 is provided with drainage circular holes with equal intervals, and the circular holes are blocked by a piston 33, the upper end of the piston 3 is flush with the upper end of the bottom of the model box, and the lower end of the piston 3 extends to the sump 2, so that the piston 3 can be taken out conveniently during rainfall;

[0034] Furthermore, the water collection trough 2 is fixed to the bottom of the model box 1 through a slot, and a drainage hole is provided on the left wall of the drainage trough 2. The drainage hole is connected to a drainage pipe 4 to drain the rainwater into a drainage box 5 provided on the left side of the model box 1; a coordinate grid is painted on the outer wall of the model box, which can be used to observe the displacement change of the slope;

[0035] The spray head 7 is fixed on the top of the model box 1, which can effectively prevent the vibration motor from interfering with the spray head 7 in simulating rainfall; the water delivery pipe 8 is connected to the spray head 7; the water in the water supply tank 17 is output to the spray head through the water delivery pipe 8, and the spray head 7 simulates rainfall; the intelligent flow control valve 19 is arranged on the water delivery pipe 8; the booster pump 18 is arranged on the left side of the intelligent flow control valve 19;

[0036] Furthermore, the intelligent flow control valve 19 is provided with an intelligently controlled servo amplifier, which can automatically perform PID adjustment according to a given value, and adjust the flow and pressure by adjusting the valve opening; the intelligent flow control valve 19 is electrically connected to an operation terminal, and the operation terminal is a computer 20, and an operator outputs an operation instruction through the operation terminal, thereby realizing intelligent and precise control of the flow and rainfall intensity, reducing errors caused by manual operation, and reducing labor costs;

[0037] The seismic module includes a vibration motor and a base; the vibration motor is fixed to the bottom of the water collection tank 2; the vibration motor is fixed to the top of the base by bolts; the four corners of the base are fixed to the ground by anchor bolts;

[0038] Further, the vibration motor includes a No. 1 vibration motor 9, a No. 2 vibration motor 10, and a No. 3 vibration motor 11; the vibration motor is a bidirectional vibration motor; the No. 2 vibration motor 10 is fixed in the middle of the bottom of the water collection tank, and the No. 1 vibration motor 9 and the No. 3 vibration motor 11 are respectively fixed on the left and right sides of the No. 2 vibration motor 10, and the distance from the No. 2 vibration motor 10 is equal; the vibration force generated by the vibration motor is transmitted to the bottom of the model box 1 through the bottom of the water collection tank 2, and then transmitted to the inside of the slope; by adjusting the installation position 12 of the No. 1 vibration motor 9 and the No. 3 vibration motor 11 on the base, the adjustment of the source position is achieved;

[0039] The monitoring module includes a pore water pressure gauge 13, an earth pressure box 14, a geotechnical data acquisition instrument and a high-speed camera 16; the earth pressure box 14 is arranged at equal intervals between the front baffle 6 of the slope and the inner wall of the model box 1. When the slope is deformed, the soil at the foot of the slope will squeeze the baffle 6, and the downward thrust of the landslide body of the slope can be measured at this time; the pore water pressure gauge 13 is arranged in layers inside the slope to monitor the change law of the pore water pressure of the soil; the pore water pressure gauge 13 is connected in series by a polyester sheathed sensing optical fiber 15, and the transmission end of the optical fiber 15 extends out of the model box and is connected to the geotechnical data acquisition instrument; the geotechnical data acquisition instrument is connected to the computer 20 operating terminal through a USB interface and transmits data; the high-speed camera 16 is arranged in the middle of the front side of the model box 1, and can take pictures and record the process of slope instability;

[0040] The model test device for the instability of granite residual soil slope under earthquake action includes the following steps:

[0041] In the first step, the drainage circular hole at the bottom of the model box 1 is blocked with a piston, and soil aggregate is filled into the model box 1 in multiple times, and the slope is cut after layered compaction; during the filling process, a pore water pressure gauge 13, an earth pressure box 14 and an optical fiber 15 are arranged at corresponding positions and connected to a geotechnical data acquisition instrument;

[0042] The second step is to fix the spray head 7 to the top of the model box 1 and connect the water pipe 8; the intelligent flow control valve 19 is electrically connected to the computer 20 to adjust the parameters and set the flow value; debug the slope top loading system and calibrate the air pressure, expansion degree, pressure bearing capacity, etc. of the air bag 23;

[0043] The third step is to pull out the piston 3 of the drainage hole 1 at the bottom of the model box, install the water collection tank 2 and the drainage device, and fix the three vibration motors in the corresponding positions;

[0044] The fourth step is to turn on the high-speed camera 16 and the switches of various instruments, observe the displacement change of the slope through the coordinate grid, collect various test data, analyze the evolution process of slope instability under the action of rainfall, slope top load and earthquake, and summarize the rules;

[0045] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A simulation monitoring method of a granite residual soil slope under a simulated earthquake during rainfall, mainly comprising a model box, a rainfall module, a seismic module and a monitoring module; a water collecting trough is provided at the bottom of the model box, a drainage hole is provided on the left wall of the water collecting trough, the drainage hole is connected to a drainage pipe, and the drainage pipe is connected to a drainage box; a water delivery pipeline, a force transmission and penetration coupler and a reaction cover are provided on the top of the model box, an intelligent flow control valve is provided on the water delivery pipeline, and a slope top loading system is provided on the reaction cover and the force transmission and penetration coupler; the seismic module comprises a vibration motor and a base, the vibration motor is fixed at the bottom of the water collecting trough, and a fixed base is provided under the vibration motor; the monitoring module comprises a pore water pressure gauge, an earth pressure box, a geotechnical data acquisition instrument and a high-speed camera, the earth pressure box is arranged between the front baffle of the slope and the inner wall of the model box, and the geotechnical data acquisition instrument collects data and transmits it to a computer operation terminal.

2. The method for simulating monitoring of granite residual soil slope during rainfall under simulated earthquake action according to claim 1 is characterized in that: The model box is made of transparent acrylic; a water collecting trough is provided at the bottom of the model box, and the water collecting trough is fixed to the model box through a slot; the bottom of the model box is provided with drainage circular holes at equal intervals; the drainage circular holes are blocked by a piston, the upper end of the piston is flush with the upper end of the bottom of the model box, and the lower end of the piston extends to the drainage trough; a drainage hole is provided on the left side wall of the drainage trough, and the drainage hole is connected to the drainage box outside the model box through a drainage pipe; drainage holes are provided on the front, rear and left side walls of the model box, and a baffle is provided on the left side of the right side wall; a coordinate grid is painted on the outer wall of the model box.

3. The method for simulating monitoring of granite residual soil slope under simulated earthquake action during rainfall according to claim 1, characterized in that: The rainfall module includes: a water supply tank, a booster pump, an intelligent flow control valve, a water pipeline, and a sprinkler head; the sprinkler head is fixed on the top of the model box; the water pipeline is connected to the sprinkler head; the intelligent flow control valve is arranged on the water pipeline; the intelligent flow control valve is electrically connected to the operation terminal, and the operation terminal is a computer.

4. The method for simulating monitoring of granite residual soil slope under simulated earthquake action during rainfall according to claim 1, characterized in that: The seismic module comprises a vibration motor and a base; the vibration motor is fixed to the bottom of the water collection tank; the vibration motor is fixed to the top of the base by bolts; and the four corners of the base are fixed to the ground.

5. The method for simulating monitoring of granite residual soil slope under simulated earthquake action during rainfall according to claim 1, characterized in that: The vibration motors include a first vibration motor, a second vibration motor, and a third vibration motor; The vibration motor is a bidirectional vibration motor; the No. 2 vibration motor is fixed in the middle of the bottom of the water collection tank, the No. 1 vibration motor is fixed on the left side of the No. 2 vibration motor, and the No. 3 vibration motor is fixed on the right side of the No. 2 vibration motor. The No. 1 vibration motor and the No. 3 vibration motor are at the same distance from the No. 2 vibration motor.

6. The method for simulating monitoring of granite residual soil slope under simulated earthquake action during rainfall according to claim 1, characterized in that: The soil pressure boxes are arranged at equal intervals between the baffle and the inner wall of the model box; the pore water pressure gauges are connected in series through polyester sheathed sensing optical fibers and arranged in layers inside the slope; the geotechnical data acquisition instrument is connected to the computer operation terminal through a USB interface and transmits data; the high-speed camera is arranged in the middle of the front side of the model box.

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