Permeation triaxial test device and test method
By using a bidirectional permeability failure mode and a permeability triaxial testing device, the problem of simulating complex stress states and fine particle behavior in soil permeability failure tests has been solved, achieving efficient and accurate permeability failure evaluation and reducing manual operation.
Patent Information
- Application Number
- CN202511060515.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-07
AI Technical Summary
Existing technologies are insufficient to accurately simulate complex stress states and the seepage behavior of fine particles in soil seepage failure tests, and lack automation, resulting in inaccurate test results and high human effort consumption.
Employing a bidirectional seepage failure mode, combined with a triaxial seepage testing device, including an equipment housing, PC operating terminal, confining pressure controller, triaxial testing module, seepage acquisition device, etc., it achieves soil-water separation and real-time collection of effluent. Equipped with fully automatic confining pressure and back pressure controllers and sensors, it simulates seepage failure modes in actual engineering projects.
It improves the automation and accuracy of the test, reduces manual operation, and can simulate the infiltration failure process under different stress conditions indoors, providing a more accurate evaluation of infiltration failure.
Smart Images
Figure CN120908059A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The soil experiment belongs to the technical field, and particularly relates to a permeation triaxial test device and an experimental method. BACKGROUND
[0002] In order to deeply study the internal erosion mechanism of the soil and the macro mechanical property change caused by the internal erosion, the influences of the consolidation pressure, the permeation pressure and the permeation time on the permeation damage process and the soil strength caused by the internal erosion of the soil are studied. The soil permeation damage deterioration test is carried out by using the self-developed soil permeation shear triaxial instrument, so that the evaluation indexes such as the water gradient and the deterioration degree of the permeation damage can be conveniently and accurately obtained, and the reference for the analysis of the soil mechanical strength deterioration caused by the permeation and the prevention and control of the permeation damage disaster in the geotechnical engineering is provided. SUMMARY
[0003] In order to solve the problems in the prior art, the present application provides a two-way permeation damage mode, which can better simulate the form of the permeation damage in the actual engineering, considers the complex stress state of the permeation damaged soil and the real permeation state of the fine particles carried out in the soil, realizes the water-soil separation, accurately collects the total volume and total mass of the outflow in real time, evaluates the permeation damage speed and the final damage condition, improves the automation degree and accuracy of the test, greatly reduces the energy consumed by the artificial in the long-term permeation test, and can carry out the soil triaxial permeation test in the laboratory.
[0004] To achieve the above object, the present application provides the following technical scheme: a permeation triaxial test device, comprising a device box body, a PC operation end and a confining pressure controller are arranged in the device box body, and the confining pressure controller is connected with a triaxial test module main body through a water pipe. The triaxial test module comprises an axial force control device at the bottom, a load frame support rod is arranged on the axial force control device, a reverse cross beam and a universal hinge are arranged on the load frame support rod, and the universal hinge is connected with an axial pressure sensor at the bottom. A multi-hole pressure chamber bottom plate is arranged on the axial force control device, the multi-hole pressure chamber bottom plate is connected with a pressure chamber through a side stand column, a sealing ring is arranged between the pressure chamber and the multi-hole pressure chamber bottom plate, a gas release valve is arranged at the top of the pressure chamber, an axial pressure loading rod is further arranged between the load frame support rod and the multi-hole pressure chamber bottom plate, a displacement sensor is arranged on the surface of the multi-hole pressure chamber bottom plate, pressure chambers are arranged on both sides above the displacement sensor, a pore pressure sensor and a confining pressure inlet are arranged at the bottom of the pressure chamber on both sides respectively, the pressure chamber at the bottom is connected with the confining pressure controller through a pipeline, and a counter pressure sensor is arranged between the confining pressure controller and the triaxial test module. The shaft pressure sensor bottom is connected with a permeation collection device, the permeation collection device is connected with a permeation pressure controller, a water storage bucket and a booster pump through pipelines in sequence.
[0005] Preferably, the permeation collection device comprises a particle screen and a particle collection cylinder.
[0006] Preferably, the booster pump can be replaced by a refillable gas cylinder and a pressure relief valve.
[0007] Preferably, the permeation collection device comprises a bottom plate, the bottom plate is provided with a particle collection device, the particle collection device is provided with a screen, and the screen is filled with sample particles.
[0008] Preferably, the permeation collection device is connected with a back pressure controller and a sample upper pressure cap through a channel a, connected with a test bottom hole and a pore pressure sensor through a channel b, connected with a pressure chamber through a channel c, connected with a sample bottom hole through a channel d, and connected with a permeation pressure control device at the right end.
[0009] An experimental method of a permeation triaxial test device, the experimental steps comprising: S1, instrument inspection: check whether the test equipment can normally operate, ensure that the air bubbles in the pore water pressure measurement system are completely discharged, the pipeline is kept unobstructed, no water leakage occurs at each connection, the pressure chamber piston rod can slide in the shaft sleeve, and the rubber membrane is checked; S2, sample preparation and installation: first, select a certain amount of representative soil samples, dry, crush, sieve, spray water on the soil and mix evenly, and stand for a period of time, then use a three-piece mold to prepare the sample by layering and compaction; The sample is placed on the upper part of the permeation collection device, the membrane holder is used to tightly wrap the outer surface of the sample and the permeation collection device, and vaseline is applied on the inner surface of the latex film to prevent seepage along the surface of the sample during the seepage process; The whole sample wrapped by the latex film is placed on the porous pressure chamber bottom plate and the steel hoop is tightened, the permeation collection device and the bottom plate are fixed, and the positions of the filter paper and the water permeable stone are paid attention to during the sample installation process, and the rubber film is tightly tied on the pressure chamber base and the sample cap by using a rubber ring; The whole sample wrapped by the latex film is placed on the porous pressure chamber bottom plate and the steel hoop is tightened, the permeation collection device and the bottom plate are fixed, and the positions of the filter paper and the water permeable stone are paid attention to during the sample installation process, and the rubber film is tightly tied on the pressure chamber base and the sample cap by using a rubber ring; S3. Sample Saturation and Consolidation: Open the confining pressure control pipeline valve and the pore pressure measurement pipeline valve. Under fixed confining pressure, open the osmotic pressure controller to saturate the sample from bottom to top. Stop saturation 10 minutes after water flows out of the outlet. Since the silt sample becomes too soft after being saturated by back pressure evacuation, it is saturated inside the pressure chamber to avoid disturbing the permeated sample. After saturation, control the confining pressure and perform B-value testing. If the sample saturation does not reach 99%, back pressure saturation should be performed again. Open the back pressure control pipeline valve. When the consolidation degree reaches 95% or more, consolidation is complete. Close the pore pressure measurement pipeline valve and the back pressure control pipeline valve, and adjust the piston rod of the pressure chamber. S4. Triaxial Permeation Test: Keep the confining pressure constant, open the valves of the upper and lower water supply pipes, and open the permeation pressure controller to conduct the test with a constant pressure head. After the permeation begins, start timing when water flows out of the outlet. When the permeation time reaches the permeation time requirement of each group, the permeation test ends and the valves of the upper and lower water supply pipes are closed. S5. Triaxial Shear Test. Select the shear strain rate and axial strain value according to the test plan, start the shearing, record the measurement data and plot it in real time on the PC. When the set axial strain value is reached, the equipment will stop automatically, close the confining pressure control pipeline valve, lower the pressure chamber, open the vent to remove the water in the pressure chamber, remove the outer cover of the pressure chamber, take out the sample and the soil in the particle collection cylinder, dry and weigh and record, and finally clean the equipment. S6. By changing the setting values of the confining pressure control unit and the osmotic pressure controller, repeat the above S1-S5 steps to simulate the occurrence and development of osmotic failure under different stress conditions.
[0010] Compared with the prior art, the beneficial effects of the present invention are: The bidirectional permeation failure mode can better simulate the form of permeation failure in actual engineering. It takes into account the complex stress state of the soil under permeation failure and the real permeation state of fine particles being carried out of the soil, realizing water and soil separation, and accurately collecting the total volume and total mass of the effluent in real time to evaluate the rate of permeation failure and the final failure situation. It improves the automation and accuracy of the test, and greatly reduces the effort spent by humans in long-term permeation tests. It can conduct triaxial permeation tests of soil indoors, and can meet the requirements of triaxial permeation tests of soil while also taking into account conventional triaxial tests of soil. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the structure of the present invention.
[0012] Figure 2 This is a schematic diagram of the experimental apparatus of the present invention.
[0013] Figure 3 This is a schematic diagram of the channel structure of the permeation device of the present invention.
[0014] Figure 4 The structure diagram of the permeation device of the present application. DETAILED DESCRIPTION
[0015] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative labor on the basis of the embodiments in the present application shall fall within the protection scope of the present application.
[0016] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Embodiment one
[0017] According to Figures 1-2 As shown in the figure, a permeation triaxial test device includes a device box 1, a PC operation end 2 and a confining pressure controller 3 are arranged inside the device box 1, and the confining pressure controller 3 is connected with a triaxial test module main body 5 through a water pipe 4; The triaxial test module 5 includes an axial force control device 510 at the bottom, a load frame support rod 511 is arranged on the axial force control device 510, a reverse cross beam and a universal hinge 512 are arranged on the load frame support rod 511, and an axial pressure sensor 55 is connected with the universal hinge 512 at the bottom; A multi-hole pressure chamber bottom plate 56 is arranged on the axial force control device 510, the multi-hole pressure chamber bottom plate 56 is bolted with a pressure chamber 52 through a side stand column, a sealing ring is arranged between the pressure chamber 52 and the multi-hole pressure chamber bottom plate 56, a gas release valve is arranged at the top of the pressure chamber 52, an axial pressure loading rod 57 is further arranged between the load frame support rod 511 and the multi-hole pressure chamber bottom plate 56, a displacement sensor 51 is arranged on the surface of the multi-hole pressure chamber bottom plate 56, pressure chambers 52 are arranged on both sides above the displacement sensor 51, hole pressure sensors 53 and confining pressure inlets 54 are arranged at both sides of the bottom of the pressure chambers 52, the pressure chambers 52 are connected to the confining pressure controller 3 through pipelines, a counter-pressure sensor 51 is arranged between the confining pressure controller 3 and the triaxial test module 5, the PC operation end 2 is connected with the axial pressure sensor 55, and the axial pressure sensor 55 is fixed at the top of the triaxial test module main body 5; The shaft pressure sensor 55 is connected with a permeation collection device 6 at the bottom, which is connected with a permeation pressure controller 61, a water storage bucket 62 and a booster pump 63 in sequence through pipelines.
[0018] The permeation collection device 6 comprises a particle screen and a particle collection cylinder.
[0019] An experimental method of a permeation triaxial test device, the experimental steps comprising: S1, instrument inspection: check whether the test equipment can normally operate, ensure that the air bubbles in the pore water pressure measurement system are completely discharged, the pipeline is kept unobstructed, no water leakage occurs at each connection, the pressure chamber piston rod can slide in the shaft sleeve, and the rubber membrane is checked; S2, sample preparation and installation: first, a certain amount of representative soil sample (1-2.5 kg) is selected, dried, crushed, sieved, water (200-400 g) is sprayed on the soil and mixed evenly, and then left for a period of time (18-36 h), and then the sample is prepared by using a three-piece mold to layer and compact; The sample is placed on the upper part of the permeation collection device, the membrane bearing cylinder is used to tightly wrap the outer surface of the rubber mold and the permeation collection device, and vaseline is applied on the inner surface of the latex film to prevent seepage along the surface of the sample during the seepage process; The whole sample covered by the latex film is placed on the porous pressure chamber base and the steel hoop is tightened, the permeation collection device and the base are fixed, and during the sample installation process, the positions of the filter paper and the water permeable stone are paid attention to, and the rubber film is tightly tied on the pressure chamber base and the sample cap by using a rubber ring; The whole sample covered by the latex film is placed on the porous pressure chamber base and the steel hoop is tightened, the permeation collection device and the base are fixed, and during the sample installation process, the positions of the filter paper and the water permeable stone are paid attention to, and the rubber film is tightly tied on the pressure chamber base and the sample cap by using a rubber ring; S3, sample saturation and consolidation: open the confining pressure control pipeline valve and the pore pressure measurement pipeline valve, open the permeation pressure controller under the fixed confining pressure, saturate the sample from bottom to top, stop saturation after 10 min after water outlet, because the saturation degree of the silt sample is too high after saturation by reverse pressure air extraction, the sample is soft and not convenient for sample installation, therefore, internal saturation of the pressure chamber is selected, which can also avoid disturbance to the permeated sample; after saturation is completed, control the confining pressure, detect the B value, when the saturation degree of the sample does not reach 99%, additional reverse pressure saturation should be performed, open the reverse pressure control pipeline valve, and when the consolidation degree reaches more than 95%, it indicates that the consolidation is completed, close the pore pressure measurement pipeline valve and the reverse pressure control pipeline valve, and adjust the pressure chamber piston rod; S4, triaxial permeation test: keep the confining pressure unchanged, open the upper and lower water pipeline valves, open the permeation pressure controller to perform the test at a constant pressure water head, start timing after water flows out of the water outlet after permeation starts, the permeation test is completed when the permeation time reaches the permeation time requirement of each group, and the upper and lower water pipeline valves are closed; S5, triaxial shear test. According to the test plan, the shear strain rate and axial strain value are selected, the shear is started, the PC end records the measurement data in real time and draws a graph, when the set axial strain value is reached, the device is automatically stopped, the confining pressure control pipeline valve is closed, the pressure chamber is lowered, the exhaust hole is opened, the water in the pressure chamber is discharged, the pressure chamber outer cover is removed, the sample and the soil in the particle collection cylinder are taken out, dried, weighed and recorded, and finally the equipment is cleaned; S6, by changing the setting value of the confining pressure control unit and the osmotic pressure controller, the test of the above S1-S5 steps is repeated to simulate the occurrence and development of osmotic damage under different stress conditions. Example two
[0020] The difference lies in the replacement of the booster pump 63, which can be replaced by a refillable gas cylinder and a pressure relief valve. Example three
[0021] As Figures 3-4 described, the difference lies in the redesign of the osmotic collection device 6, which includes a bottom plate 601, the bottom plate 601 is provided with a particle collection device 602, the particle collection device 602 is provided with a screen 603, and the screen 603 is filled with sample particles 604.
[0022] The osmotic collection device 6 is connected to the back pressure controller and the upper pressure cap of the pattern through channel a, connected to the test bottom hole and the pore pressure sensor 53 through channel b, connected to the pressure chamber 52 through channel c, connected to the sample bottom hole through channel d, and connected to the osmotic pressure control device at the right end, which can realize the saturation process from bottom to top in the sample, and realize the downward permeation path; channel d and channel a are connected with a water pipe, and a three-way valve is arranged at the joint, by adjusting the valve, the osmotic pressure of the osmotic pressure control device can be introduced from the pressure cap connected by channel a, and the sample is subjected to the upward permeation path.
[0023] Working principle: Since osmotic damage is the phenomenon of fine particles in soil moving along the pores formed by skeleton particles under the action of seepage, under the condition that the pore diameter formed by coarse particles in soil is greater than the diameter of fine particles, the seepage of water in soil leads to a sharp increase in pore water pressure, making the effective stress of fine particles zero, and driving fine particles to move between pores. In order to simulate the actual working condition, the test sample is placed in the pressure chamber which can apply triaxial pressure, the gas pressure in the water collecting tank is controlled by the osmotic pressure controller to provide pressure water head, the soil-water mixture after permeation can enter the particle collection cylinder through the screen and be saved, until the permeation is completed, the pressure water head is closed, the axial pressure is applied by the axial pressure loading rod in the strain control mode, and the test is completed when the given axial strain value is reached.
[0024] The two-way permeation damage mode can better simulate the form of permeation damage in actual engineering, and the added permeation path is suitable for different types and gradations of test samples, and has obvious advantages compared with the commonly used one-way seepage of the existing test device. The complex stress state of the permeation damaged soil body and the real permeation state of the fine particles carried out of the soil body are considered, a full-automatic confining pressure and counter-pressure controller is equipped, an axial pressure sensor, a pore pressure sensor and a displacement sensor are connected with a PC operation end, each module can work independently, the soil body is not disturbed during the test process, the maximum permeation pressure head of the equipment can reach 1 MPa, the confining pressure can reach 2 MPa, the stress state simulation of the underground soil body in most actual engineering is met, the pressure sensor with a pressure accuracy of 0.3% and the displacement sensor system with an accuracy of 0.001 mm are adopted, and the accuracy of the test data is ensured. The permeation collection device can realize the water-soil separation in a relatively ideal manner, and can accurately collect the total volume and total mass of the gushing material in real time, so as to evaluate the permeation damage speed and the final damage condition, improve the automation degree and accuracy of the test, and greatly reduce the energy consumed by manual work in long-term permeation test. The soil triaxial permeation test can be carried out in the laboratory, and the soil triaxial permeation test can be met while the conventional triaxial test of the soil can be considered.
[0025] The above shows and describes the basic principles and main features of the present application and the advantages of the present application, and it is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or basic characteristics of the present application; therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, and any reference signs in the claims should not be regarded as limiting the involved claims.
[0026] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A triaxial permeation test apparatus comprising an apparatus housing, characterised in that: The device box is internally provided with a PC operation end and a confining pressure controller, and the confining pressure controller is connected with a triaxial test module main body through a water pipe; The triaxial test module comprises an axial force control device at the bottom, a load frame support rod is arranged on the axial force control device, a reverse cross beam and a universal hinge are arranged on the load frame support rod, and the universal hinge is connected with an axial pressure sensor at the bottom; A multi-hole pressure chamber base plate is arranged on the axial force control device, the multi-hole pressure chamber base plate is connected with a pressure chamber through side columns and bolts, a sealing ring is arranged between the pressure chamber and the multi-hole pressure chamber base plate, a deflation valve is arranged at the top of the pressure chamber, an axial pressure loading rod is further arranged between the load frame support rod and the multi-hole pressure chamber base plate, a displacement sensor is arranged on the surface of the multi-hole pressure chamber base plate, pressure chambers are arranged on both sides of the displacement sensor, a pore pressure sensor and a confining pressure inlet are arranged at the bottom of the pressure chamber on both sides respectively, the pressure chamber is connected with the confining pressure controller through a pipeline, and a counter pressure sensor is arranged between the confining pressure controller and the triaxial test module, the PC operation end is connected with the axial pressure sensor, and the axial pressure sensor is fixed on the top of the triaxial test module main body; The axial pressure sensor is connected with a permeation collection device, and the permeation collection device is sequentially connected with a permeation pressure controller, a water storage bucket and a booster pump through pipelines.
2. The triaxial permeation test apparatus according to claim 1, wherein The permeation collection device comprises a particle screen and a particle collection cylinder.
3. The triaxial permeation test apparatus according to claim 1, wherein The booster pump can be replaced by a refillable gas cylinder and a pressure relief valve.
4. The triaxial permeation test apparatus according to claim 1, wherein The permeation collection device comprises a bottom plate, a particle collection device is arranged on the bottom plate, a screen is arranged on the particle collection device, and sample particles are filled in the screen.
5. The triaxial permeation test apparatus according to claim 1, wherein The permeation collection device is connected with a counter pressure controller and a sample upper pressure cap through a channel a, is connected with a test bottom hole and a pore pressure sensor through a channel b, is connected with a pressure chamber through a channel c, is connected with a sample bottom hole through a pressure chamber, and is connected with a permeation pressure control device at the right end.
6. A method of conducting an experimental permeation triaxial test, characterized by: The experimental steps comprise: S1, instrument inspection: check whether the test equipment can normally operate, ensure that the pore water pressure measurement system is completely free of air bubbles, the pipeline is kept unobstructed, no water leakage occurs at each connection, the pressure chamber piston rod can slide in the shaft sleeve, and the rubber membrane is checked; S2, sample preparation and installation: first, a certain amount of representative soil sample is selected, dried, crushed, sieved, water is sprayed on the soil material, stirred and placed for a period of time, and then a three-piece mold is used to prepare the sample by layering and compaction; The sample is placed on the upper part of the permeation collection device, the rubber mold is tightly wrapped around the outer surface of the sample and the permeation collection device by using a film bearing cylinder, and vaseline is applied on the inner surface of the latex film to prevent seepage along the surface of the sample during the seepage process; The whole sample wrapped by the latex film is placed on the multi-hole pressure chamber base plate and the steel hoop is tightened, the permeation collection device and the base plate are fixed, and attention is paid to the positions of the filter paper and the water permeable stone during the sample installation process, and the rubber film is tightly tied on the pressure chamber base and the sample cap by using a rubber ring; The whole sample wrapped by the latex film is placed on the multi-hole pressure chamber base plate and the steel hoop is tightened, the permeation collection device and the base plate are fixed, and attention is paid to the positions of the filter paper and the water permeable stone during the sample installation process, and the rubber film is tightly tied on the pressure chamber base and the sample cap by using a rubber ring; S3, sample saturation consolidation: open the confining pressure control pipeline valve and pore pressure measurement pipeline valve, fix the confining pressure, open the permeation pressure controller from bottom to top, saturate the sample, stop saturation after 10 minutes after the water outlet, because the silt sample is saturated by back pressure air extraction, the saturation degree is too high, the sample is soft and not convenient to load, so choose to saturate inside the pressure chamber, which can avoid disturbance to the permeated sample; after saturation, control the confining pressure and detect B value, if the saturation degree of the sample does not reach 99%, additional back pressure saturation should be performed. Open the back pressure control pipeline valve, when the degree of consolidation reaches more than 95%, it indicates that the consolidation is completed, close the pore pressure measurement pipeline valve and back pressure control pipeline valve, adjust the pressure chamber piston rod; S4, triaxial permeation test: keep the confining pressure unchanged, open the upper and lower water pipeline valves, open the permeation pressure controller to conduct the test with constant pressure water head, after the permeation starts, start timing when water flows out of the water outlet, when the permeation time reaches the permeation time requirement of each group, the permeation test is completed, close the upper and lower water pipeline valves; S5, triaxial shear test: according to the test plan, select the shear strain rate and axial strain value, start shear, PC end records the measurement data and draws the graph in real time, when the set axial strain value is reached, the device automatically stops, close the confining pressure control pipeline valve, lower the pressure chamber, open the exhaust hole, remove the water in the pressure chamber, remove the pressure chamber outer cover, take out the sample and the soil in the particle collection cylinder, dry and weigh to record, finally clean the equipment; S6, by changing the setting values of the confining pressure control unit and the permeation pressure controller, repeat the test of S1-S5 steps to simulate the development of permeation failure under different stress conditions.