A test system and method for testing the strength of the structural surface of the reservoir bank drawdown zone

Abstract

The present invention discloses a test system and method for testing the strength of the structural surface of the drawdown zone of a reservoir bank, including a water tank system, a fan system, a soil strength test system under the influence of natural conditions, a soil strength test system under the influence of dry-wet cycles, and a soil strength test system in an immersion saturated zone; the water tank system includes a water tank and a steel frame chair, and the water tank is placed above the steel frame chair; three water outlets are arranged on the water tank in equal intervals from left to right, and each water outlet is provided with a water outlet pipeline. The structural device of the present invention is simple and easy to assemble, the device structure is reasonably designed, the processing and manufacturing are simple, the components are convenient to disassemble and assemble, the parts are easy to replace and transport, and the structural surface under different working conditions of the drawdown zone of the reservoir bank can be realized, and the disturbance caused by the removal of the structural surface sample causes the change of the sample to be tested, so that the test data is more accurate and effective.

Description

Technical Field

[0001] The invention relates to a rock and soil structural surface strength monitoring method, and in particular to a reservoir bank drawdown zone structural surface strength testing system and method. Background Art

[0002] Studying the strength characteristics of the structural surface of the drawdown zone of the reservoir bank is of great significance for studying the influence of weakening strength of the soil mass in the drawdown zone on the stability of landslides. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a test system and method for testing the strength of the structural surface of the reservoir bank drawdown zone, which has an axial loading device on the top of the sample and a confining pressure loading device on the side; at the same time, the structural surface strength monitoring of different areas of the reservoir bank drawdown zone can be simulated by controlling the water immersion degree of the sample, and the device is simple and easy to assemble.

[0004] The reservoir bank drawdown zone structural surface strength test system of the present invention is realized by the following technical scheme: It includes a water tank system, a fan system, a soil strength test system under the influence of natural conditions, a soil strength test system under the influence of dry-wet cycles, and a soil strength test system in a soaking saturated zone;

[0005] The water tank system includes a water tank and a steel frame chair, and the water tank is placed above the steel frame chair; three water outlets are arranged on the water tank at equal intervals from left to right, and each water outlet is provided with a water outlet pipe; the water outlet pipe is connected with the soil strength test system under the influence of natural conditions, the soil strength test system under the influence of dry-wet cycles, and the soil strength test system in the immersion saturated zone, and a water flow control valve is provided on the water outlet pipe.

[0006] The fan system includes a fan with adjustable wind temperature and a ventilation duct, and the fan is connected to a soil strength test system under the influence of natural conditions and a soil strength test system under the influence of dry-wet cycles through the ventilation duct.

[0007] As the preferred technical scheme, the soil strength test system under the influence of natural conditions and the soil strength test system under the influence of dry-wet cycles are both composed of a sample tank, a sample tube, an exciter, a deformation meter and an air pressure device; the sample tank is filled with the sample to be tested, and a water hole is arranged on the side of the sample tank; the sample tank is provided with a switch for controlling the water hole, the sample tube is fixed outside the sample tank and connected with a water inlet pipe, a water outlet pipe, an air inlet pipe and an air outlet pipe for water inlet and outlet and ventilation; a jack, a pressure sensor, a pressure display, an exciter and a deformation meter are fixed on the top of the sample tank, and include a mounting seat and a power part; a water pressure gauge is fixed outside the sample tube, and a pipeline switch is arranged on the water inlet pipe, the water outlet pipe, the air inlet pipe and the air outlet pipe; the water inlet pipe is connected to the water outlet pipeline, and the air inlet pipe is connected to the ventilation duct;

[0008] The saturated zone soil strength test system is also composed of a sample tank, a sample tube, an exciter, a deformation meter and an air pressure device; the sample tank is filled with the sample to be tested, and a water hole is set on the side of the sample tank; the sample tank is provided with a switch for controlling the water hole, and the sample tube is fixed outside the sample tank and connected with a water inlet pipe and a water outlet pipe for water inlet and outlet and ventilation; the jack, pressure sensor, pressure display exciter, exciter and deformation meter are fixed on the top of the sample tank, and include a mounting seat and a power part; a water pressure gauge is fixed outside the sample tube, and pipeline switches are set on the water inlet pipe and the water outlet pipe; the water inlet pipe is connected to the water outlet pipeline, and the air inlet pipe is connected to the ventilation duct.

[0009] As a preferred technical solution, the water permeable holes of the soil strength testing system under natural conditions are 0.2 cm, the water permeable holes of the soil strength testing system under the influence of dry-wet cycles are 0.5 cm, and the water permeable holes of the soil strength testing system in the immersion saturated zone are 0.8 cm; a base is fixed underneath the soil strength testing system under natural conditions, the soil strength testing system under the influence of dry-wet cycles, and the soil strength testing system in the immersion saturated zone.

[0010] As a preferred technical solution, the water outlet pipe is a straight water outlet pipe, the ventilation duct consists of a straight pipe and a curved pipe, and the straight pipe is connected to the fan, the soil strength test system under natural conditions, and the soil strength test system under the influence of dry-wet cycles. The curved pipe is used to connect the straight pipe, and the curved pipe has an S-shaped bend structure.

[0011] As a preferred technical solution, the air pressure device is composed of an air pressure bottle, an air pressure regulating valve, a barometer, and an air pressure tube. The air pressure tube is connected to the air pressure bottle, and the air pressure bottle is fixed to the bottom of the sample loading tube.

[0012] As an optimal technical solution, the mounting seat is in the shape of a circular tube, and the mounting seat is fixedly connected to the top of the sample loading tube. The power part is an oil cylinder, and the oil cylinder is a bidirectional double-acting low-friction sealed hydraulic cylinder; the cylinder barrel of the oil cylinder is in the shape of a disc and the axis coincides with the axis of the mounting seat, and the edge of the cylinder barrel is fixedly connected to one end of the mounting seat. The piston rod of the oil cylinder can move linearly reciprocatingly relative to the cylinder barrel, and the piston rod passes through the mounting seat and both ends are located outside the mounting seat, and one end extends into the sample loading groove; the strain meter is fixed to the top of the sample, and is used to detect the vertical displacement of the sample when the exciter applies stress to the sample.

[0013] A test method for testing the strength of a reservoir bank drawdown zone structure surface comprises the following steps:

[0014] S1. Preparation of structural surface samples: Process the structural surface samples retrieved from the soil layer to be tested into circular specimens with a diameter of 10 cm, and then tie the upper and lower parts of the structural surface with steel wire ropes;

[0015] S2. Sample installation: remove the pressure device and the strain gauge, then put the prepared sample into the sample slot, and cut off the iron wire previously tied to the structural surface and remove it; then reinstall the pressure device and the strain gauge;

[0016] S3, soil strength test under simulated natural conditions, soil strength test under dry-wet cycle conditions and soil strength test in saturated zone;

[0017] S4. Stress application: After the soil sample to be tested reaches the simulation condition, a loading jack is used to apply a predetermined stress, and the stress applied by the jack is increased step by step until the vertical displacement of the soil sample reaches the set value.

[0018] As a preferred technical solution, in S3, the soil strength test method under simulated natural conditions is as follows:

[0019] Under natural conditions, rainfall and wind have an impact on soil strength. Therefore, after the soil sample to be tested is fixed in the sample slot, the water flow control valve of the water tank is opened, and the water stop valve of the water inlet pipe and the water stop valve of the water outlet pipe of the sample tube a are opened to allow water to flow for 10 minutes to simulate natural rainfall. After 10 minutes of water flow, the fan is turned on, and the air inlet control valve and the air outlet control valve are opened to ventilate for 10 minutes to simulate wind action. Due to different weather conditions in different regions, the water and ventilation time is also different.

[0020] As a preferred technical solution, in S3, the soil strength test method under the influence of simulated dry-wet cycle conditions is as follows:

[0021] Close all water flow stop valves, open the water flow regulator of the water tank, open the water inlet stop valve of the sample tube b, and allow water to slowly flow into the sample tube b until the entire sample tube is filled, and record the water pressure of the water pressure gauge; soak the sample in water for 4 hours, then close the water inlet stop valve of the sample tube b, open the water outlet stop valve of the sample tube b, and after all the water in the sample tube flows out, open the fan and the valve switch of the ventilation duct, adjust the fan temperature to 50℃, ventilate for 2 hours, and then close the fan and ventilation valve; repeat the above operation 5 times under the same water pressure condition, that is, complete 5 dry-wet cycles, and the number of dry-wet cycles is determined according to the length of time the local reservoir was built;

[0022] As a preferred technical solution, in S3, the soil strength test method for simulating immersion saturated zone is as follows:

[0023] Close all water stop valves, open the water flow regulator of the water tank, open the water inlet pipe stop valve of the sample tube c, and allow the water to slowly flow into the sample tube c until it fills the entire sample tube. At the same time, record the water pressure of the water pressure gauge, immerse the soil to be tested until pressurized using the jack; at the same time, add water to the water tank to simulate the soil strength under different water pressures.

[0024] The beneficial effects of the present invention are:

[0025] 1. The structural device of the present invention is simple and easy to assemble, the device structure is reasonably designed, the processing and manufacturing are simple, the components are easy to disassemble and assemble, the parts are easy to replace and transport, and the structural surface under different working conditions of the reservoir bank drawdown zone can be realized.

[0026] 2. The present invention overcomes the problem of disturbance caused by taking out the structural surface sample, which leads to changes in the sample to be tested, making the test data more accurate and effective.

[0027] 3. The present invention adopts multiple devices to improve the test efficiency. The water in the device can be replaced with other solutions to detect the soil strength of the soil sample in a corrosive environment and simulate the chemical reaction of water and rock. At the same time, the vibrator can also study the mechanical properties of simulated rock and soil under dynamic action. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the planar structure of the present invention;

[0030] Figure 2 It is a water tank system diagram of the present invention;

[0031] Figure 3 A fan system diagram of the present invention;

[0032] Figure 4 It is a diagram of the soil strength test system under natural conditions and the influence of dry-wet cycles of the present invention;

[0033] Figure 5 This is a diagram of the immersion saturated zone soil strength test system of the present invention;

[0034] Figure 6 It is a sample tank housing diagram of the present invention;

[0035] Figure 7 It is the shear strength envelope diagram of the present invention. DETAILED DESCRIPTION

[0036] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0037] Any feature disclosed in this specification (including any additional claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0038] In the description of the present invention, it is necessary to understand that the terms "one end", "the other end", "outside", "upper", "inside", "horizontal", "coaxial", "center", "end", "length", "outer end" and the like 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.

[0039] In addition, in the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0040] Terms such as "upper", "above", "lower", "below", etc. used in the present invention to indicate spatial relative positions are used for the purpose of convenience to describe the relationship of one unit or feature relative to another unit or feature as shown in the accompanying drawings. Terms of spatial relative position may be intended to include different orientations of the device in use or operation other than the orientation shown in the drawings. For example, if the device in the figure is turned over, the unit described as being "below" or "beneath" other units or features will be located "above" the other units or features. Therefore, the exemplary term "below" can encompass both the above and below orientations. The device may be oriented in other ways, and the spatially related descriptors used herein shall be interpreted accordingly.

[0041] In the present invention, unless otherwise clearly defined and limited, the terms "disposed", "socketed", "connected", "through", "inserted" 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 or an electrical connection; 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.

[0042] like Figure 1 — Figure 6 As shown, a reservoir bank drawdown zone structural surface strength test system and method of the present invention includes a water tank system 500, a fan system 100, a soil strength test system 200 under natural conditions, a soil strength test system 300 under dry-wet cycle influence, and a saturated zone soil strength test system 400;

[0043] The water tank system includes a water tank 1 and a steel frame chair 3, and the water tank 1 is placed above the steel frame chair 3; three water outlets are arranged on the water tank 1 at equal intervals from left to right, and each water outlet is provided with a water outlet pipe 4; the water outlet pipe 4 is connected with a soil strength test system 200 under the influence of natural conditions, a soil strength test system 300 under the influence of dry-wet cycles, and a soil strength test system 400 in an immersion saturated zone, and a water flow control valve 2 is arranged on the water outlet pipe 4, and the water flow control valve 2 is used to control the water flow size, and water enters different sample tubes through the water inlet pipe; the steel frame chair 3 is used to provide a certain height for the water tank so that water can enter the sample tube through the water inlet pipe.

[0044] The fan system includes a fan 5 and a ventilation duct 6 with adjustable wind temperature, and the fan 5 is connected to the soil strength test system 200 under natural conditions and the soil strength test system 300 under dry-wet cycle through the ventilation duct 6. The fan system can simulate the influence of wind on rock soil under natural conditions and accelerate the evaporation of water in rock soil during dry-wet cycle by adjusting the fan power. The fan is connected to the air inlet pipe, and there is a pipeline switch at the air inlet pipe to control whether the wind can pass into the sample tube.

[0045] In this embodiment, the soil strength test system 200 under the influence of natural conditions and the soil strength test system 300 under the influence of dry-wet cycles are both composed of a sample tank 24, a sample tube 15, an exciter, a deformation meter 22 and a pneumatic device; the sample tank 24 contains a sample to be tested, and a water hole 26 is provided on the side of the sample tank 24; the sample tank 24 is provided with a switch 25 for controlling the water hole 26, the sample tube 15 is fixed to the outside of the sample tank 24 and is connected with a water inlet pipe, a water outlet pipe 11, an air inlet pipe and an air outlet pipe 13 for water inlet and outlet and ventilation; the jack, the pressure sensor, the pressure display, the exciter and the deformation meter 22 are used for ventilation. 2 is fixed on the top of the sample tank 24, and includes a mounting seat 19 and a power part; a water pressure gauge is fixed on the outside of the sample tube 15, and pipeline switches are provided on the water inlet pipe, the water outlet pipe 11, the air inlet pipe and the air outlet pipe 13, and the pipeline switches are respectively used to control the water inlet and outlet and ventilation; the water inlet pipe is connected to the water outlet pipe 4, and the air inlet pipe is connected to the ventilation pipe 6; the jack is used to apply pressure to the sample, the pressure sensor transmits the pressure, the pressure display is used to display the applied pressure, and the deformation meter is used to detect the deformation of the sample under the applied pressure; the water pressure gauge is fixed on the outer surface of the sample tube, and is used to detect the water pressure in the closed sample tube;

[0046] The saturated zone soil strength test system 400 is also composed of a sample tank 24, a sample tube 15, an exciter, a strain gauge 22 and a pneumatic device; the sample tank 24 contains a sample to be tested, and a water hole 26 is provided on the side of the sample tank 24; the sample tank 24 is provided with a switch 25 for controlling the water hole 26, the sample tube 15 is fixed outside the sample tank 24 and connected with a water inlet pipe and a water outlet pipe 11 for water inlet and outlet and ventilation; the jack, pressure sensor, pressure display exciter, exciter and strain gauge 22 are fixed on the top of the sample tank 24 The sample tube 15 is provided with a water pressure gauge, and the water inlet pipe and the water outlet pipe 11 are provided with pipeline switches, which are used to control the water inlet and outlet respectively; the water inlet pipe is connected to the water outlet pipe 4, and the air inlet pipe is connected to the ventilation pipe 6; the jack is used to apply pressure to the sample, the pressure sensor transmits the pressure, the pressure display is used to display the applied pressure, and the deformation meter is used to detect the deformation of the sample under the applied pressure; the water pressure gauge is fixed on the outer surface of the sample tube, and is used to detect the water pressure in the closed sample tube.

[0047] In this embodiment, the water permeable hole 26 of the soil strength testing system 200 under the influence of natural conditions is 0.2 cm, the water permeable hole 26 of the soil strength testing system 300 under the influence of dry-wet cycles is 0.5 cm, and the water permeable hole 26 of the immersion saturated zone soil strength testing system 400 is 0.8 cm, so that water can penetrate the sample and the sample can seep water under the action of external pressure; a base 10 is fixed underneath the soil strength testing system 200 under the influence of natural conditions, the soil strength testing system 300 under the influence of dry-wet cycles, and the immersion saturated zone soil strength testing system 400 to fix the sample tubes of the three systems so that the vibrator can be pressurized.

[0048] In this embodiment, the water outlet pipe 4 is a straight water outlet pipe, the ventilation duct 6 is composed of a straight pipe and a curved pipe, and the straight pipe is connected to the fan 5, the soil strength test system 200 under the influence of natural conditions, and the soil strength test system 300 under the influence of dry-wet cycles. The curved pipe is used to connect the straight pipe, and the curved pipe has an S-shaped bend structure.

[0049] In this embodiment, the air pressure device is composed of a pressure bottle 7, a pressure regulating valve 8, a barometer 9, and a pressure tube 16. The pressure tube 16 is connected to the pressure bottle 7, and the pressure bottle 7 is fixed to the bottom of the sample tube 15; the pressure bottle is filled with gas to provide air pressure, the pressure regulating valve is used to control the air pressure, the barometer is used to display the amount of applied air pressure, and the pressure tube is used to connect the pressure bottle and fix it inside the sample tube to apply ambient pressure.

[0050] In this embodiment, the mounting seat 19 is in the shape of a circular tube, and the mounting seat 19 is fixedly connected to the top of the sample loading tube 15. The power part is the oil cylinder 20, and the oil cylinder 20 is a bidirectional double-acting low-friction sealed hydraulic oil cylinder; the cylinder barrel of the oil cylinder 20 is in the shape of a disc and the axis coincides with the axis of the mounting seat 19. The edge of the cylinder barrel is fixedly connected to one end of the mounting seat 19. The piston rod 23 of the oil cylinder 20 can move linearly back and forth relative to the cylinder barrel. The piston rod 23 passes through the mounting seat 19 and both ends are located outside the mounting seat 19, and one end extends into the sample loading groove; the strain meter is fixed to the top of the sample, and is used to detect the vertical displacement of the sample when the exciter applies stress to the sample.

[0051] In this embodiment, the sample tube is made of white transparent fiberglass, and the sample slot is made of flexible material with a thickness of 3-5 mm and good elasticity;

[0052] A test method for testing the strength of a reservoir bank drawdown zone structure surface comprises the following steps:

[0053] S1. Preparation of structural surface samples: Process the structural surface samples retrieved from the soil layer to be tested into circular specimens with a diameter of 10 cm, and then tie the upper and lower parts of the structural surface with steel wire ropes;

[0054] S2. Sample installation: remove the pressure device and the strain gauge, then put the prepared sample into the sample slot, and cut off the iron wire previously tied to the structural surface and remove it; then reinstall the pressure device and the strain gauge;

[0055] S3, soil strength test under simulated natural conditions, soil strength test under dry-wet cycle conditions and soil strength test in saturated zone;

[0056] S4. Stress application: After the soil sample to be tested reaches the simulation condition, a loading jack is used to apply a predetermined stress, and the stress applied by the jack is increased step by step until the vertical displacement of the soil sample reaches the set value; in the triaxial shear test designed based on the Mohr-Coulomb strength theory, the sample is subjected to a fixed ambient pressure and the axial pressure is gradually increased until the sample is destroyed, based on which a limit stress circle can be drawn; 3 to 4 specimens of the same soil sample are tested under different ambient pressures to obtain a set of limit stress circles, and the common tangents of these limit stress circles are drawn, which are the shear strength envelope of the soil sample, and the shear strength index of the soil sample can be obtained, such as Figure 7 shown.

[0057] In this embodiment, in S3, the soil strength test method under simulated natural conditions is as follows:

[0058] Under natural conditions, rainfall and wind have an impact on soil strength. Therefore, after the soil sample to be tested is fixed in the sample slot, the water flow control valve of the water tank is opened, and the water stop valve of the water inlet pipe and the water stop valve of the water outlet pipe of the sample tube a are opened to allow water to flow for 10 minutes to simulate natural rainfall. After 10 minutes of water flow, the fan is turned on, and the air inlet control valve and the air outlet control valve are opened to ventilate for 10 minutes to simulate wind action. Due to different weather conditions in different regions, the water and ventilation time is also different.

[0059] In this embodiment, in S3, the soil strength test method under the influence of simulated dry-wet cycle conditions is as follows:

[0060] Close all water flow stop valves, open the water flow regulator of the water tank, open the water inlet stop valve of the sample tube b, and allow water to slowly flow into the sample tube b until the entire sample tube is filled, and record the water pressure of the water pressure gauge; soak the sample in water for 4 hours, then close the water inlet stop valve of the sample tube b, open the water outlet stop valve of the sample tube b, and after all the water in the sample tube has flowed out, open the fan and the valve switch of the ventilation duct, adjust the fan temperature to 50°C, ventilate for 2 hours, and then close the fan and ventilation valve; repeat the above operation 5 times under the same water pressure condition, that is, complete 5 dry-wet cycles, and the number of dry-wet cycles is determined according to the length of time the local reservoir was built; after the dry-wet cycle, close the fan 5, the switch of the ventilation pipe 6, the water outlet stop valve 12 and the switch 26, so that the sample tube is filled with water, and then open the air pressure regulating valve to pressurize it, Then use the preset stress of the vibrator and gradually increase the stress applied by the vibrator until the vertical displacement of the soil sample reaches the set value; record the surrounding pressure value and vertical pressure value at this moment; take out the sample and change the surrounding pressure, repeat the above process, and obtain the surrounding pressure value and vertical pressure value of several groups of soil sample failure.

[0061] In this embodiment, in S3, the method for testing the soil strength in the simulated immersion saturated zone is as follows:

[0062] Close all water stop valves, open the water flow regulator of the water tank, open the water inlet pipe stop valve of the sample tube c, and allow the water to slowly flow into the sample tube c until it fills the entire sample tube. At the same time, record the water pressure of the water pressure gauge, immerse the soil to be tested until pressurized using the jack; at the same time, add water to the water tank to simulate the soil strength under different water pressures.

[0063] In summary, the test system and method for testing the structural surface strength of the bank drawdown zone has an axial loading device on the top of the sample and a confining pressure loading device on the side. At the same time, the structural surface strength monitoring of different areas of the bank drawdown zone can be simulated by controlling the water immersion degree of the sample, and the device is simple and easy to combine.

[0064] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A test system for testing the strength of the structural surface of a reservoir bank drawdown zone, characterized by: It comprises a water tank system (500), a fan system (100), a soil strength test system under the influence of natural conditions (200), a soil strength test system under the influence of dry-wet cycles (300) and a saturated zone soil strength test system (400); The water tank system comprises a water tank (1) and a steel frame chair (3), wherein the water tank (1) is placed above the steel frame chair (3); three water outlets are arranged on the water tank (1) at equal intervals from left to right, and each water outlet is provided with a water outlet pipeline (4); the water outlet pipeline (4) is connected to a soil strength test system (200) under the influence of natural conditions, a soil strength test system (300) under the influence of dry-wet cycles, and a soil strength test system (400) in an immersion saturated zone, and a water flow control valve (2) is provided on the water outlet pipeline (4). The fan system comprises a fan (5) capable of adjusting wind temperature and a ventilation duct (6), and the fan (5) is connected to a soil strength test system (200) under the influence of natural conditions and a soil strength test system (300) under the influence of dry-wet cycles through the ventilation duct (6); The soil strength testing system (200) under the influence of natural conditions and the soil strength testing system (300) under the influence of dry-wet cycles are both composed of a sample tank (24), a sample loading tube (15), an exciter, a deformation meter (22) and a pneumatic device; the sample tank (24) contains a sample to be tested, and a water permeable hole (26) is provided on the side of the sample tank (24); the sample tank (24) is provided with a switch (25) for controlling the water permeable hole (26), and the sample loading tube (15) is fixed to the outside of the sample tank (24) and connected to the sample tank (24). A water inlet pipe, a water outlet pipe (11), an air inlet pipe and an air outlet pipe (13) are connected for water inlet and outlet and ventilation; a jack, a pressure sensor, a pressure display, an exciter and a strain gauge (22) are fixed on the top of the sample tank (24), and include a mounting seat (19) and a power part; a water pressure gauge is fixed outside the sample loading tube (15), and pipeline switches are arranged on the water inlet pipe, the water outlet pipe (11), the air inlet pipe and the air outlet pipe (13); the water inlet pipe is connected to the water outlet pipeline (4), and the air inlet pipe is connected to the ventilation pipeline (6); The saturated zone soil strength test system (400) is also composed of a sample tank (24), a sample loading tube (15), an exciter, a strain gauge (22) and a pneumatic device; the sample tank (24) contains a sample to be tested, and a water permeable hole (26) is provided on the side of the sample tank (24); the sample tank (24) is provided with a switch (25) for controlling the water permeable hole (26); the sample loading tube (15) is fixed outside the sample tank (24) and connected with a water inlet pipe and a water outlet pipe (11) for water inlet and outlet and ventilation; the jack, pressure sensor, pressure display exciter, exciter and strain gauge (22) are fixed on the top of the sample tank (24) and include a mounting seat (19) and a power part; a water pressure gauge is fixed outside the sample loading tube (15), and pipeline switches are provided on the water inlet pipe and the water outlet pipe (11); the water inlet pipe is connected to the water outlet pipeline (4), and the air inlet pipe is connected to the ventilation pipeline (6).

2. The reservoir bank drawdown zone structural surface strength test system according to claim 1 is characterized by: The water permeable hole (26) of the soil strength testing system (200) under the influence of natural conditions is 0.2 cm, the water permeable hole (26) of the soil strength testing system (300) under the influence of dry-wet cycles is 0.5 cm, and the water permeable hole (26) of the immersion saturated zone soil strength testing system (400) is 0.8 cm; a base (10) is fixed below the soil strength testing system (200) under the influence of natural conditions, the soil strength testing system (300) under the influence of dry-wet cycles, and the immersion saturated zone soil strength testing system (400).

3. The reservoir bank drawdown zone structural surface strength test system according to claim 1 is characterized by: The water outlet pipe (4) is a straight water outlet pipe, the ventilation duct (6) is composed of a straight pipe and a curved pipe, and the straight pipe is connected to the fan (5), the soil strength test system under natural conditions (200) and the soil strength test system under dry-wet cycle (300), the curved pipe is used to connect the straight pipe, and the curved pipe has an S-shaped bent structure.

4. The reservoir bank drawdown zone structural surface strength test system according to claim 1 is characterized by: The air pressure device is composed of an air pressure bottle (7), an air pressure regulating valve (8), a barometer (9), and an air pressure pipe (16). The air pressure pipe (16) is connected to the air pressure bottle (7), and the air pressure bottle (7) is fixed to the bottom of the sample loading tube (15).

5. The reservoir bank drawdown zone structural surface strength test system according to claim 1 is characterized by: The mounting seat (19) is in the shape of a circular tube. The mounting seat (19) is fixedly connected to the top of the sample loading tube (15). The power part is an oil cylinder (20). The oil cylinder (20) is a bidirectional double-acting low-friction sealed hydraulic oil cylinder. The cylinder barrel of the oil cylinder (20) is in the shape of a circular disc and its axis coincides with the axis of the mounting seat (19). The edge of the cylinder barrel is fixedly connected to one end of the mounting seat (19). The piston rod (23) of the oil cylinder (20) can move linearly back and forth relative to the cylinder barrel. The piston rod (23) passes through the mounting seat (19) and its two ends are located outside the mounting seat (19), and one end thereof extends into the sample loading groove. The strain gauge is fixed to the top of the sample and is used to detect the vertical displacement of the sample when the sample is subjected to stress by the exciter.

6. A test method for testing the strength of the structural surface of the reservoir bank drawdown zone, characterized in that: The test system for testing the structural surface strength of the bank drawdown zone according to any one of claims 1 to 5 comprises the following steps: S1. Preparation of structural surface samples: Process the structural surface samples retrieved from the soil layer to be tested into circular specimens with a diameter of 10 cm, and then tie the upper and lower parts of the structural surface with steel wire ropes; S2. Sample installation: remove the pressure device and the strain gauge, then put the prepared sample into the sample slot, and cut off the iron wire previously tied to the structural surface and remove it; then reinstall the pressure device and the strain gauge; S3, soil strength test under simulated natural conditions, soil strength test under dry-wet cycle conditions and soil strength test in saturated zone; S4. Stress application: After the soil sample to be tested reaches the simulation condition, a loading jack is used to apply a predetermined stress, and the stress applied by the jack is increased step by step until the vertical displacement of the soil sample reaches the set value.

7. The test method for testing the strength of the structure surface of the bank drawdown zone according to claim 6 is characterized in that: In S3, the soil strength test method under simulated natural conditions is as follows: In natural conditions, rainfall and wind both have an impact on soil strength. Therefore, after the soil sample to be tested is fixed in the sample slot, open the water flow control valve of the water tank, and at the same time open the water stop valve of the water inlet pipe and the water stop valve of the water outlet pipe of the sample tube a to allow water to flow for 10 minutes to simulate natural rainfall. After 10 minutes of water flow, turn on the fan, open the air inlet control valve and the air outlet control valve, and ventilate for 10 minutes to simulate wind action. Due to different weather conditions in different regions, the water and ventilation time is also different.

8. The test method for testing the strength of the structure surface of the bank drawdown zone according to claim 6 is characterized in that: In S3, the soil strength test method under the influence of simulated dry-wet cycle conditions is as follows: Close all water flow stop valves, open the water flow regulator of the water tank, open the water inlet stop valve of the sample tube b, and allow water to slowly flow into the sample tube b until it fills the entire sample tube. At the same time, record the water pressure on the water pressure gauge; soak the sample in water for 4 hours, then close the water inlet stop valve of the sample tube b, and open the water outlet stop valve of the sample tube b. After all the water in the sample tube has flowed out, open the fan and the valve switch of the ventilation duct, adjust the fan temperature to 50℃, ventilate for 2 hours, and then close the fan and ventilation valve; repeat the above operation 5 times under the same water pressure condition, that is, complete 5 dry-wet cycles. The number of dry-wet cycles is determined according to the length of time the local reservoir was built.

9. The test method for testing the strength of the structure surface of the bank drawdown zone according to claim 6 is characterized in that: In S3, the soil strength test method for simulating immersion saturated zone is as follows: Close all water stop valves, open the water flow regulator of the water tank, open the water inlet pipe stop valve of the sample tube c, and allow the water to slowly flow into the sample tube c until it fills the entire sample tube. At the same time, record the water pressure of the water pressure gauge, immerse the soil to be tested until pressurized using the jack; at the same time, add water to the water tank to simulate the soil strength under different water pressures.

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