Soil triaxial test device capable of independently loading confining pressure and axial pressure

Abstract

The invention discloses a soil body triaxial test device capable of independently loading confining pressure and axial pressure, and relates to the technical field of soil stress measuring devices, the soil body triaxial test device comprises a base, a hydraulic pump, a pressure applying piece, a pressure chamber and a cylindrical soft film container, the pressure chamber is fixedly connected to the base, the soft film container is located in the pressure chamber, and the hydraulic pump is connected with the pressure applying piece. The interior of the soft film container is filled with to-be-detected soil; the bottom of the soft film container abuts against and is attached to the bottom of the pressure chamber, a window is formed in the center of the top of the pressure chamber, an opening of the soft film container is embedded in the inner wall of the window in a sealed mode, and a cover is arranged at the opening of the soft film container; a pressure cavity is formed between the inner wall of the pressure chamber and the peripheral side face of the soft film container, and a discharge port of the hydraulic pump is communicated with the pressure cavity through a pipeline, so that on one hand, the device is not influenced by axial pressure in the confining pressure testing process, and on the other hand, the axial pressure and the confining pressure can be changed to simulate different stress environments of soil to be tested; and the diversity of the test is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of soil stress measuring devices, in particular to a soil triaxial testing device with independent loading of confining pressure and axial pressure. Background Art

[0002] The triaxial apparatus is an instrument used to measure the mechanical properties of soil, such as shear strength. It is mainly composed of a pressure chamber, an axial loading system, a confining pressure system, a pore water pressure measurement system, a deformation measurement system, etc. Its core component is the pressure chamber, which can accommodate soil samples and apply axial pressure (axial pressure) and lateral pressure (confining pressure) to the samples during the test.

[0003] The patent with announcement number CN210665305U discloses an embedded geotechnical triaxial apparatus, which includes a sample base and a pressure cover; the sample is placed on the sample base of the pressure chamber and connected to the sample cap on the top of the sample; the sample is wrapped with a waterproof rubber membrane; the sample is connected to the pore water pressure sensor through a pore water pressure tube; and is connected to the surrounding pressure control system through a surrounding pressure connecting tube; the pressure chamber base is fixed on the lifting spindle of the test bench, the pressure chamber is placed in the pressure chamber of the original test instrument, the pore water drainage pipe is connected to the pore water measuring pipe of the original test instrument through a connecting valve and then connected to the pore water pressure sensor, and the back pressure connecting pipe is connected to the back pressure measuring pipe of the original test instrument through a valve and then connected to the back pressure control system.

[0004] In the prior art such as the above patent, the triaxial instrument adopts full-enclosed hydraulic loading when loading the lateral force. In this way, as long as the confining pressure is loaded, it must also be loaded in the vertical direction, and the test form is single. Summary of the invention

[0005] The object of the present invention is to provide a soil triaxial test device with independent loading of confining pressure and axial pressure, so as to solve the deficiencies in the above-mentioned prior art.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a soil triaxial test device with independent loading of confining pressure and axial pressure, comprising a base, a hydraulic pump, a pressure member, a pressure chamber and a cylindrical soft film container, wherein the pressure chamber is fixedly connected to the base, the soft film container is located in the pressure chamber, and the interior of the soft film container is used to fill the soil to be tested; the bottom of the soft film container abuts against the bottom of the pressure chamber, a window is provided at the top center of the pressure chamber, the mouth of the soft film container is sealed and embedded in the inner wall of the window, and a cover is provided at the mouth of the soft film container; a pressure chamber is formed between the inner wall of the pressure chamber and the peripheral side of the soft film container, and the discharge port of the hydraulic pump is connected to the pressure chamber through a pipeline.

[0007] Furthermore, it also includes a water injector and a water absorber. The cover is connected to a water injection pipe, and the other end of the water injection pipe is connected to the output port of the water injector. The bottom of the soft film container is connected to a water outlet pipe, and the water outlet pipe extends outside the pressure chamber. The other end of the water outlet pipe is connected to the suction port of the water absorber.

[0008] Furthermore, the pressure member includes a hydraulic cylinder, which includes a cylinder body and a piston rod. The cylinder body is fixedly connected to a base frame on the base, and a cylindrical pressure plate is fixedly connected to the piston rod. The peripheral side wall of the pressure plate can fit the inner wall of the soft film container.

[0009] Furthermore, an exhaust port is provided at the top of the pressure chamber, and a rubber plug is provided at the exhaust port.

[0010] Furthermore, the bottom of the soft film container and the bottom of the cover are both provided with a permeable stone layer.

[0011] Furthermore, a port is provided at the bottom of the pressure chamber, and a pipe of the drainage outlet of the hydraulic pump is connected to the port.

[0012] Furthermore, the peripheral side wall of the pressure chamber is made of organic glass.

[0013] In the above technical scheme, the present invention provides a soil triaxial test device with independent loading of confining pressure and axial pressure. First, pressure liquid is injected into the pressure chamber in the pressure chamber through a pressure pump. After the pressure chamber is filled with pressure liquid, the pressure liquid will squeeze the peripheral side wall of the soft film container. In this process, the top and the bottom of the soft film container are not affected by the pressure liquid. Then, the soil to be tested inside the soft film container is only subjected to the effect of the confining pressure. The lid of the soft film container is opened and axial pressures of different forces are applied to the soil through the pressure-applying member. In this process, the axial pressure and the confining pressure cooperate. On the one hand, this device can be unaffected by the axial pressure during the test of the confining pressure. On the other hand, the axial pressure and the confining pressure can be changed to simulate different stress environments of the soil to be tested, thereby effectively improving the diversity of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0015] Figure 1 A schematic diagram of the overall structure of the device provided by an embodiment of the present invention; Figure 2 A schematic diagram of a cross-sectional structure of a pressure chamber provided in an embodiment of the present invention; Figure 3A schematic diagram of the top structure of a pressure chamber provided in an embodiment of the present invention.

[0016] Description of reference numerals: 1. Base; 2. Pressure member; 21. Pressure plate; 3. Pressure chamber; 31. Window; 32. Exhaust port; 321. Rubber plug; 33. Port; 4. Soft film container; 41. Soil to be tested; 42. Cover; 5. Water injector; 51. Water injection pipe; 6. Water absorber; 61. Water outlet pipe; 7. Permeable stone layer. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0018] See also Figure 1-3 The embodiment of the present invention provides a soil triaxial test device with independent loading of confining pressure and axial pressure, comprising a base 1, a hydraulic pump, a pressure member 2, a pressure chamber 3 and a cylindrical soft film container 4, wherein the pressure chamber 3 is fixedly connected to the base 1, the soft film container 4 is located in the pressure chamber 3, and the interior of the soft film container 4 is used to fill the soil 41 to be tested; the bottom of the soft film container 4 is abutted against the bottom of the pressure chamber 3, a window 31 is provided at the top center of the pressure chamber 3, the mouth of the soft film container 4 is sealed and embedded in the inner wall of the window 31, and the mouth of the soft film container 4 is provided with Cover 42; a pressure chamber is formed between the inner wall of the pressure chamber 3 and the peripheral side of the soft film container 4, and the discharge port of the hydraulic pump is connected to the pressure chamber through a pipeline. Specifically, the pressure-applying member 2 includes a hydraulic cylinder, and the hydraulic cylinder includes a cylinder body and a piston rod. The cylinder body is fixedly connected to a base frame on the base 1, and a cylindrical pressure plate 21 is fixedly connected to the piston rod. The peripheral side wall of the pressure plate 21 can fit the inner wall of the soft film container 4, wherein the peripheral side wall of the pressure chamber 3 is made of organic glass material, and a port 33 is provided at the bottom of the pressure chamber 3, and the pipe of the discharge port of the hydraulic pump is connected to the port 33.

[0019] Working principle: There are two test conditions for the soil 41 to be tested, one is the separate test of axial pressure and confining pressure, and the other is the test of axial pressure and confining pressure together. When the axial pressure and confining pressure are tested separately, pressurized water is first injected into the pressure cavity in the pressure chamber 3 through a hydraulic pump (the hydraulic pump is a prior art, not shown in the figure). Since the bottom of the soft film container 4 fits the bottom of the pressure chamber 3 and the top cover 42 seals the window 31 embedded in the pressure chamber 3, the pressurized water can only act on the peripheral wall of the soft film container 4, generating confining pressure on the peripheral wall of the soft film container 4, and the pressure sensor of the triaxial instrument forms data for the induced confining pressure (the data conversion of the pressure sensor is a prior art, which is not described here). Then the data of the confining pressure is obtained; then, the pressurized water is discharged to replace the new soil 41 to be tested, and the piston rod of the hydraulic cylinder pushes the pressure plate 21 to vertically extrude the soil to generate axial pressure, and then the axial pressure data is obtained through the pressure sensor; the data of the axial pressure and the confining pressure are obtained separately; when the axial pressure and the confining pressure are tested together, the soft film container 4 does not need a cover 42, but the top of the soil in the soft film container 4 fits with the pressure plate 21, and then pressurized water is injected into the pressure cavity of the pressure chamber 3, and the axial pressure and confining pressure of the soil 41 to be tested are changed by the cooperation of the hydraulic pump and the piston rod, so as to realize more simulated environments of the soil 41 to be tested being subjected to different axial pressures and confining pressures, so that the test environment is more comprehensive.

[0020] In the above technical scheme, the present invention provides a soil triaxial test device with independent loading of confining pressure and axial pressure. First, pressure liquid is injected into the pressure cavity in the pressure chamber 3 through a pressure pump. After the pressure cavity is filled with pressure liquid, the pressure liquid will squeeze the peripheral side wall of the soft film container 4. During this process, the top and the bottom of the soft film container 4 are not affected by the pressure liquid. Then, the soil 41 to be tested inside the soft film container 4 is only subjected to the effect of the confining pressure. The lid 42 of the soft film container 4 is opened and axial pressures of different forces are applied to the soil through the pressure member 2. During this process, the axial pressure and the confining pressure cooperate. On the one hand, this device can be unaffected by the axial pressure during the test of the confining pressure. On the other hand, the axial pressure and the confining pressure can be changed to simulate the stress environment of different soils 41 to be tested, thereby effectively improving the diversity of the test.

[0021] Among them, it also includes a water injector 5 and a water absorber 6. The cover 42 is connected with a water injection pipe 51, and the other end of the water injection pipe 51 is connected to the output port of the water injector 5. The bottom of the soft film container 4 is connected with a water outlet pipe 61, which extends to the outside of the pressure chamber 3, and the other end of the water outlet pipe 61 is connected to the suction port of the water absorber 6. In an actual soil environment, when water in the surrounding soil penetrates into the soil to be subjected to confining pressure, it will affect its confining pressure. This is mainly because the penetration of water will change the pore water pressure of the soil, thereby affecting the effective confining pressure. The device can inject water into the soil to be tested 41 in the soft film container 4 through the injector and the water injection pipe 51, thereby simulating the environment in which the surrounding soil penetrates water into the soil to be tested 41, and then simulate the dry environment of the soil through the water absorber 6. The effect of water seepage into the surrounding on the confining pressure of the soil to be tested 41; it is worth mentioning that the injection of water into the soil to be tested 41 will also affect the axial pressure test. The axial pressure test simulates different test environments of soil axial pressure, making the test simulation environment more comprehensive.

[0022] Among them, an exhaust port 32 is opened on the top of the pressure chamber 3, and a rubber plug 321 is provided at the exhaust port 32. In the triaxial test, if a saturated soil sample is tested, the main function of the exhaust port 32 is to exhaust the air in the soil sample. When the soil sample is placed in the pressure chamber 3, the soil is saturated by injecting water into the pressure chamber 3.

[0023] The bottom of the soft film container 4 and the bottom of the cover 42 are both provided with a permeable stone layer 7. The permeable stone generally has good permeability and uniform pore structure. During the drainage process, it can make the pore water discharge evenly, avoiding the test error caused by local poor drainage (the permeable stone layer 7 is not required when studying the undrained shear strength of saturated soft clay).

[0024] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A soil triaxial test device with independent loading of confining pressure and axial pressure, comprising a base (1), a hydraulic pump, a pressure member (2), a pressure chamber (3) and a cylindrical soft film container (4), wherein the pressure chamber (3) is fixedly connected to the base (1), the soft film container (4) is located in the pressure chamber (3), and the interior of the soft film container (4) is used to fill the soil (41) to be tested; characterized in that: The bottom of the soft film container (4) is abutted against the bottom of the pressure chamber (3), a window (31) is provided at the center of the top of the pressure chamber (3), the mouth of the soft film container (4) is sealed and embedded in the inner wall of the window (31), and a lid (42) is provided at the mouth of the soft film container (4); A pressure chamber is formed between the inner wall of the pressure chamber (3) and the peripheral side of the soft film container (4), and the discharge port of the hydraulic pump is connected to the pressure chamber through a pipeline.

2. A soil triaxial test device with independent loading of confining pressure and axial pressure according to claim 1, characterized in that: It also includes a water injector (5) and a water absorber (6), wherein the cover (42) is connected to a water injection pipe (51), the other end of the water injection pipe (51) is connected to the output port of the water injector (5), and the bottom of the soft film container (4) is connected to a water outlet pipe (61), the water outlet pipe (61) extends to the outside of the pressure chamber (3), and the other end of the water outlet pipe (61) is connected to the suction port of the water absorber (6).

3. The soil triaxial test device with independent loading of confining pressure and axial pressure according to claim 1 is characterized in that: The pressure member (2) comprises a hydraulic cylinder, which comprises a cylinder body and a piston rod. The cylinder body is fixedly connected to a base frame on the base (1). A cylindrical pressure plate (21) is fixedly connected to the piston rod. The peripheral side wall of the pressure plate (21) can fit the inner wall of the soft film container (4).

4. The soil triaxial test device with independent loading of confining pressure and axial pressure according to claim 1 is characterized in that: An exhaust port (32) is provided at the top of the pressure chamber (3), and a rubber plug (321) is provided at the exhaust port (32).

5. The soil triaxial test device with independent loading of confining pressure and axial pressure according to claim 1 is characterized in that: The bottom of the soft film container (4) and the bottom of the cover (42) are both provided with a permeable stone layer (7).

6. The soil triaxial test device with independent loading of confining pressure and axial pressure according to claim 1 is characterized in that: A port (33) is provided at the bottom of the pressure chamber (3), and a pipe of a drainage outlet of the hydraulic pump is in communication with the port (33).

7. The soil triaxial test device with independent loading of confining pressure and axial pressure according to claim 1 is characterized in that: The peripheral side wall of the pressure chamber (3) is made of organic glass.

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