CN114428024A - Shear apparatus for freeze-thaw cycle shear test and test method - Google Patents
Shear apparatus for freeze-thaw cycle shear test and test method Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0003—Steady
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0025—Shearing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0222—Temperature
- G01N2203/0228—Low temperature; Cooling means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/025—Geometry of the test
- G01N2203/0258—Non axial, i.e. the forces not being applied along an axis of symmetry of the specimen
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0682—Spatial dimension, e.g. length, area, angle
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0694—Temperature
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Abstract
The invention relates to the technical field of test devices and test methods thereof, in particular to a shear apparatus for a freeze-thaw cycle shear test and a test method thereof, which comprises a shear apparatus main body, a refrigeration system and a data acquisition system; the intelligent control of the internal environment temperature of the shear box is realized through the connection of the shear apparatus and external refrigeration equipment, the automatic acquisition of dynamic reaction values in the freeze-thaw cycle and the shearing process of the soil sample is realized through the temperature sensor embedded in the soil sample, the pressure sensor, the dynamometer and the horizontal displacement meter which are installed at the top of the pressure rod, and the automatic acquisition of the dynamic reaction values in the freeze-thaw cycle and the shearing process of the soil sample is realized.
Description
Technical Field
The invention relates to the technical field of test devices and test methods thereof, in particular to a shear apparatus for a freeze-thaw cycling shear test and a test method thereof.
Background
As the third frozen soil of China, the frozen soil is widely distributed and is mostly located in earthquake regions, so that the mechanical properties of corresponding foundation soil are extremely complex. Particularly in a seasonal frozen soil area, the surface soil body is frozen along with the reduction of the air temperature, and a stable and clear freeze-thaw interface is formed in the soil body. Generally, the dynamic shear modulus and the damping ratio of the frozen soil are respectively 30-50 times and 2 times of those of the molten soil, and the frozen soil has the characteristics of nonlinearity, hysteresis property, strain accumulation property and the like under the action of cyclic load. Therefore, the strain of the soil body at the freezing and thawing interface is discontinuous, and the mechanical property is in step type mutation. Plastic slippage can also occur at the freezing and thawing interface under the action of earthquake, causing more serious damage,
shear strength is one of the important mechanical properties of soil, and the foundation, roadbed bearing capacity and stability of various slopes of a building are all controlled by the shear strength of the soil (see Zhao, Shu Xiao, Wang Shi ban Xiang. soil mechanics and basic engineering [ M ]. Wuhan: Wuhan Riji university Press, 2014: 99.). The shear test using a shear apparatus is a means for testing the shear strength of soil at present, and generally, a cylindrical sample is used in the shear test, the sample is placed in a shear box, the shear rate is electrically controlled, the internal friction angle and the cohesion are further measured, and the shear strength is obtained by applying the coulomb theory (see lie, shanxi, soil shear strength test method discussion [ J ] talent intelligence, 2012(36): 29.). However, the shear strength testing instruments for soil bodies on the market at present are mainly designed for non-frozen soil, and the shear strength testing instruments have the characteristics of simple operation, mature technology, capability of testing the shear strength of the molten soil only, incapability of testing the shear strength of a freeze-thaw interface and recording dynamic changes of horizontal force and horizontal displacement in real time, complex formation process of a field actual freeze-thaw interface, large influence of temperature and the like. At present, due to the small size of a soil sample and the limited function of a testing device, the internal temperature change cannot be monitored and measured in real time in the shear test.
Therefore, in order to accurately acquire the shear strength of the freeze-thaw interface, the internal temperature change is monitored in real time, and the forming process of the actual freeze-thaw interface is simulated more truly. Designing a set of reasonable and effective freeze-thaw cycle shear tester device and test method is very necessary, and has great significance for scientific research and practice work of engineering construction in cold regions.
Disclosure of Invention
Aiming at the problems, in order to simulate a freeze-thaw interface more truly, measure the shear strength accurately and realize the effective control of the temperature in the freeze-thaw cycle shearing process and the real-time measurement of the temperature, the stress and the strain of each soil layer in the test process, the invention aims to provide a shearing instrument device and a test method for the freeze-thaw cycle shearing test, which can simultaneously monitor the change of the temperature, the change of the stress and the shear displacement of each soil layer in the freeze-thaw cycle shearing process and the measurement, can be used for simulating the temperature change of foundation soil in a cold area environment, testing the dynamic change quantity of the stress, the strain, the temperature and the like in the freeze-thaw cycle shearing process of the foundation soil of a highway or a railway in the cold area, and can realize the automatic real-time monitoring and collection of the temperature, the stress, the strain and the like in the freeze-thaw cycle shearing process by connecting a built-in sensor with an external data acquisition instrument and a computer.
In order to realize the purpose of the invention, the invention provides the following technical scheme:
a shear apparatus for a freeze-thaw cycle shear test comprises a shear apparatus main body, a refrigeration system and a data acquisition system;
the shearing apparatus main body comprises a pressure rod, a heat preservation layer, an upper shearing box, a lower shearing box, a permeable plate, an upper permeable stone, a horizontal thrust rod, a shearing transmission mechanism, a rolling shaft, a bottom plate, a lower permeable stone and a supporting plate, wherein the lower shearing box is arranged at the top of the supporting plate, the rolling shaft is arranged at the bottom of the supporting plate, the horizontal thrust rod is arranged at one side of the supporting plate, the shearing transmission mechanism is arranged at the bottom of the horizontal thrust rod, the shearing transmission mechanism and the rolling shaft are both arranged at the top of the bottom plate, a boss is arranged at the top of the bottom plate, the upper shearing box is arranged at the top of the lower shearing box, the upper permeable stone is arranged in the upper shearing box, the lower permeable stone is arranged in the lower shearing box, the permeable plate is positioned at the top of the lower permeable stone, and the heat preservation layer is wrapped outside the upper shearing box and the lower shearing box, the pressure rod is arranged on the top of the upper permeable stone;
the refrigeration system is composed of a first cold liquid inlet pipe, a first cold liquid outlet pipe, a second cold liquid inlet pipe, a second cold liquid outlet pipe and external cold bath equipment, wherein the first cold liquid inlet pipe and the first cold liquid outlet pipe are both arranged on the upper permeable stone, and the second cold liquid inlet pipe and the second cold liquid outlet pipe are both arranged on the lower shearing box;
the data acquisition system comprises pressure sensor, dynamometer, horizontal displacement meter, temperature sensor lead wire, soil sample model, counterforce device, data acquisition equipment and computer, pressure sensor installs on the pressure pole, soil sample model installs in shearing appearance main part, temperature sensor installs in soil sample model, dynamometer and temperature sensor lead wire are all installed on counterforce device's horizontal pole, the one end and the temperature sensor of temperature sensor lead wire are connected, and the other end of temperature sensor lead wire is drawn forth and is connected with data acquisition equipment through the sensor lead wire hole, and data acquisition equipment is connected with the computer signal.
The invention is further configured to: the heat-insulating layer is wrapped outside the upper shearing box and the lower shearing box.
The invention is further configured to: the heat preservation layer is made of a heat preservation material with the thickness of 20 mm.
The invention is further configured to: and the first cold liquid inlet pipe, the first cold liquid outlet pipe, the second cold liquid inlet pipe and the second cold liquid outlet pipe are communicated with external cold bath equipment.
The invention is further configured to: and after the lead of the temperature sensor is led out of the upper shearing box and the lower shearing box, the lead hole of the sensor is sealed by adopting a heat-insulating material.
The invention is further configured to: the counterforce device is arranged at the top of the boss.
The invention also provides an experimental method for the freeze-thaw cycling shear test, which comprises the following steps:
(1) placing the prepared soil sample model in an experimental shearing box consisting of an upper shearing box and a lower shearing box according to a test scheme, arranging temperature sensors at test point positions, wrapping the upper shearing box and the lower shearing box by using a heat-insulating material, and forming a heat-insulating layer around the experimental shearing box;
(2) the temperature sensor is connected through a temperature sensor lead wire and then led out of a sensor lead wire hole of the experiment shearing box to be connected with data acquisition equipment;
(3) vertically connecting a pressure rod to the center of the upper permeable stone, installing a pressure sensor on the pressure rod, and installing a horizontal displacement meter and a dynamometer on a horizontal rod of a counterforce device;
(4) connecting a first cold liquid inlet pipe, a first cold liquid outlet pipe, a second cold liquid inlet pipe and a second cold liquid outlet pipe with external cold bath equipment, and switching on a power supply;
(5) and after the test is started, the external cold bath equipment is started to perform cold bath, refrigerating fluid enters the external cold bath equipment through the first cold fluid inlet pipe and the second cold fluid inlet pipe respectively, and returns to the external cold bath equipment through the first cold fluid outlet pipe and the second cold fluid outlet pipe after circulating for a week, so that the soil sample is subjected to a shear test.
The invention is further configured to: in step (5), in the shear test process, the data acquisition equipment acquires data at an interval of once every 10min, and the acquired data is analyzed by a computer.
Advantageous effects
Compared with the known public technology, the technical scheme provided by the invention has the following beneficial effects:
(1) according to the invention, the experiment shear box is connected with external cold bath equipment, so that the effective control of the internal environment temperature of the shear box is realized, and the purpose of simulating the freezing and thawing environment of the foundation soil in cold regions is achieved.
(2) The temperature sensor is arranged in the experiment shear box, so that the temperature change of different parts of the sample model can be monitored.
(3) The internal dynamometer and the horizontal displacement meter are arranged in the shear test device, so that the internal horizontal force and the change of horizontal displacement during the shear test of the sample model can be tested, and the real-time monitoring of stress and strain is further realized.
(4) The 20mm heat insulation material is arranged outside the box body of the experimental shearing instrument, so that the heat exchange inside and outside the shearing instrument can be effectively isolated, and the aim of improving the cooling effect is fulfilled.
(5) When the shearing apparatus provided by the invention is used, the shearing apparatus has the advantages of stable work, easy operation, accurate data measurement and the like.
Drawings
FIG. 1 is a schematic side view of a shear apparatus of the present invention;
FIG. 2 is a schematic top view of the shear apparatus of the present invention;
FIG. 3 is an elevational view of the shear apparatus of the present invention;
FIG. 4 is a graph showing the measured freeze-thaw cycle temperature change of a soil sample in example 3 of the present invention;
FIG. 5 is a graph showing the relationship between the shear strength and the vertical pressure of the soil sample measured in example 3 of the present invention.
The reference numbers in the figures illustrate:
1. a pressure sensor; 2. a pressure lever; 3. a first cold liquid inlet pipe; 4. a first cold liquid outlet pipe; 5. a heat-insulating layer; 6. a force gauge; 7. an upper shearing box; 8. a lower shear box; 9. a water permeable plate; 10. a horizontal displacement meter; 11. coating permeable stones; 12. a temperature sensor; 13. a second cold liquid inlet pipe; 14. a second cold liquid outlet pipe; 15. a horizontal thrust rod; 16. a shearing transmission mechanism; 17. a roller; 18. a base plate; 19. laying permeable stones; 20. a temperature sensor lead; 21. a soil sample model; 22. a counterforce device; 23. and (7) a supporting plate.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to achieve the effects of the present invention, the present invention will be further described with reference to the following examples.
Example 1:
referring to fig. 1-3, a shear apparatus for a freeze-thaw cycle shear test comprises a shear apparatus body, a refrigeration system and a data acquisition system; the shearing apparatus main body comprises a pressure rod 2, a heat-insulating layer 5, an upper shearing box 7, a lower shearing box 8, a water-permeable plate 9, an upper water-permeable stone 11, a horizontal thrust rod 15, a shearing transmission mechanism 16, a roller 17, a bottom plate 18, a lower water-permeable stone 19 and a supporting plate 23, wherein the lower shearing box 8 is arranged at the top of the supporting plate 23, the roller 17 is arranged at the bottom of the supporting plate 23, the horizontal thrust rod 15 is arranged at one side of the supporting plate 23, the shearing transmission mechanism 16 is arranged at the bottom of the horizontal thrust rod 15, the shearing transmission mechanism 16 and the roller 17 are both arranged at the top of the bottom plate 18, a boss is arranged at the top of the bottom plate 18, the upper shearing box 7 is arranged at the top of the lower shearing box 8, the upper water-permeable stone 11 is arranged in the upper shearing box 7, the lower water-permeable stone 19 is arranged in the lower shearing box 8, the water-permeable plate 9 is positioned at the top of the lower water-permeable stone 19, the heat-insulating layer 5 is wrapped outside the upper shearing box 7 and the lower shearing box 8, the pressure rod 2 is arranged on the top of the upper permeable stone 11; the refrigerating system consists of a first cold liquid inlet pipe 3, a first cold liquid outlet pipe 4, a second cold liquid inlet pipe 13, a second cold liquid outlet pipe 14 and external cold bath equipment, wherein the first cold liquid inlet pipe 3 and the first cold liquid outlet pipe are both arranged on the upper permeable stone 11, and the second cold liquid inlet pipe 13 and the second cold liquid outlet pipe 14 are both arranged on the lower shearing box 8; the data acquisition system is by pressure sensor 1, the dynamometer 6, horizontal displacement meter 10, temperature sensor 12, the temperature sensor lead wire 20, soil sample model 21, reaction device 22, data acquisition equipment and computer are constituteed, pressure sensor 1 installs on pressure pole 2, soil sample model 21 installs in the shearing machine main part, temperature sensor 12 installs in soil sample model 21, dynamometer 6 and temperature sensor lead wire 20 are all installed on reaction device 22's horizontal pole, the one end and the temperature sensor 12 of temperature sensor lead wire 20 are connected, and the other end of temperature sensor lead wire 20 is drawn forth through the sensor pin hole and is connected with data acquisition equipment, data acquisition equipment and computer signal connection.
In the embodiment, the arranged supporting plate 23 plays a role in supporting the experimental shear box formed by the upper shear box 7 and the lower shear box 8, intelligent control of the internal environment temperature of the experimental shear box is realized through connection of the shear instrument main body and external refrigeration equipment, and automatic collection of dynamic reaction values (such as stress, strain, temperature and the like) in the freeze-thaw cycle and the shearing process of the soil sample is realized through the temperature sensor 12 embedded in the soil sample, the pressure sensor 1 installed at the top of the pressure rod 2, the dynamometer 6 and the horizontal displacement meter 10.
In the present invention, the insulating layer 5 is wrapped around the outside of the upper and lower shear boxes 7 and 8.
In this embodiment, a good heat insulating effect can be achieved by the provided heat insulating layer 5.
In the invention, the heat-insulating layer 5 is made of a heat-insulating material with the thickness of 20 mm.
In this embodiment, the thermal insulation material used can be selected according to the use requirement, and is not cumbersome here.
In the invention, a first cold liquid inlet pipe 3, a first cold liquid outlet pipe 4, a second cold liquid inlet pipe 13 and a second cold liquid outlet pipe 14 are all communicated with external cold bath equipment.
In this embodiment, the cooling liquid enters through the first cooling liquid inlet pipe 3 and the second cooling liquid inlet pipe 13, and returns to the external cooling bath device through the first cooling liquid outlet pipe 4 and the second cooling liquid outlet pipe 14 after circulating for one week.
In the invention, after the temperature sensor lead 20 is led out of the upper shear box 7 and the lower shear box 8, the sensor lead hole is sealed by adopting a heat insulation material.
In this embodiment, seal the sensor pin hole through insulation material, can avoid the heat to scatter and disappear to improve the precision nature of this experiment.
In the present invention, the reaction force device 22 is mounted on top of the boss.
In this embodiment, a boss is provided to provide support for the reaction device 22.
Example 2:
on the basis of example 1, the invention also provides an experimental method for a freeze-thaw cycling shear test, which comprises the following steps:
(1) according to the test scheme, the prepared soil sample model 21 is placed in an experiment shearing box consisting of an upper shearing box 7 and a lower shearing box 8, meanwhile, the temperature sensors 12 are arranged at the test point positions, the upper shearing box 7 and the lower shearing box 8 are wrapped by heat-insulating materials, and a heat-insulating layer 5 is formed around the experiment shearing box;
(2) the temperature sensor 12 is connected through a temperature sensor lead 20 and then led out of a sensor lead hole of the experimental shear box to be connected with data acquisition equipment;
(3) vertically connecting a pressure rod 2 to the center of an upper permeable stone 11, installing a pressure sensor 1 on the pressure rod 2, and installing a horizontal displacement meter 10 and a dynamometer 6 on a horizontal rod of a counterforce device 22;
(4) connecting a first cold liquid inlet pipe 3, a first cold liquid outlet pipe 4, a second cold liquid inlet pipe 13 and a second cold liquid outlet pipe 14 with external cold bath equipment, and switching on a power supply;
(5) and after the test is started, the external cold bath equipment is started to perform cold bath, refrigerating fluid enters the external cold bath equipment through the first cold fluid inlet pipe 3 and the second cold fluid inlet pipe 13 respectively, and returns to the external cold bath equipment through the first cold fluid outlet pipe 4 and the second cold fluid outlet pipe 14 after circulating for a week, so that the soil sample is subjected to a shear test.
Furthermore, in the shearing test process, data acquisition equipment acquires data at an interval of once every 10min, and the acquired data are analyzed by a computer.
Example 3:
to illustrate the better tests performed on the present invention, a freeze-thaw cycle shear test was performed on soil samples having dimensions of 200mm x 200mm (diameter x height) using the present invention. The test soil sample is selected from Lanzhou loess, the particle size d is less than or equal to 2mm, and the initial water content is 16%.
The method in example 2 is used to perform a shear test on a test soil sample, and the test mainly tests the elements of the soil sample, such as temperature, horizontal displacement, horizontal force, vertical pressure and the like.
Fig. 4 shows the temperature profile over time for two freeze-thaw cycles of a soil sample, as can be seen from fig. 4: the temperature change curve is changed regularly, and when the temperature is reduced, the temperature is kept in a certain stable process, and then the temperature is returned. The temperature is a direct basis for the heat distribution and transfer of the soil body, and the curve represents the temperature change characteristic in the freeze-thaw cycle process in the test process.
FIG. 5 shows the shear strength versus vertical pressure, i.e., the shear strength versus vertical pressure curve of a soil sample after freeze-thaw cycling. According to the principle of direct shear test, namely under different vertical pressures, the maximum horizontal shear force is measured, a straight line is drawn by taking the vertical pressure as the abscissa and the maximum horizontal shear force as the ordinate, and the vertical pressure is as follows according to the basic formula: tau isfAnd (4) obtaining the soil sample shear strength index cohesive force c and internal friction angle phi by adding the index c + tan phi.
The test results show that the test device can ensure the realization of the freeze-thaw cycle process and the real-time measurement of the temperature change in the freeze-thaw process, can simply and accurately measure the elements such as the shear stress, the shear displacement, the vertical pressure and the like of the sample after the freeze-thaw cycle in real time, and further accurately obtain the relation curve of the shear strength and the vertical pressure, thereby obtaining the shear strength index of the sample.
Claims (8)
1. A shear apparatus for a freeze-thaw cycle shear test is characterized by comprising a shear apparatus main body, a refrigeration system and a data acquisition system;
the shearing apparatus main body comprises a pressure rod (2), a heat preservation layer (5), an upper shearing box (7), a lower shearing box (8), a water permeable plate (9), an upper permeable stone (11), a horizontal thrust rod (15), a shearing transmission mechanism (16), a rolling shaft (17), a bottom plate (18), a lower permeable stone (19) and a supporting plate (23), wherein the lower shearing box (8) is installed at the top of the supporting plate (23), the rolling shaft (17) is installed at the bottom of the supporting plate (23), the horizontal thrust rod (15) is installed at one side of the supporting plate (23), the shearing transmission mechanism (16) is installed at the bottom of the horizontal thrust rod (15), the shearing transmission mechanism (16) and the rolling shaft (17) are both installed at the top of the bottom plate (18), a boss is installed at the top of the bottom plate (18), the upper shearing box (7) is installed at the top of the lower shearing box (8), and the upper permeable stone (11) is installed in the upper shearing box (7), the lower permeable stone (19) is arranged in the lower shearing box (8), the permeable plate (9) is positioned at the top of the lower permeable stone (19), the heat-insulating layer (5) is wrapped outside the upper shearing box (7) and the lower shearing box (8), and the pressure rod (2) is arranged at the top of the upper permeable stone (11);
the refrigeration system is composed of a first cold liquid inlet pipe (3), a first cold liquid outlet pipe (4), a second cold liquid inlet pipe (13), a second cold liquid outlet pipe (14) and external cold bath equipment, wherein the first cold liquid inlet pipe (3) and the first cold liquid outlet pipe are both arranged on an upper permeable stone (11), and the second cold liquid inlet pipe (13) and the second cold liquid outlet pipe (14) are both arranged on a lower shearing box (8);
the data acquisition system consists of a pressure sensor (1), a dynamometer (6), a horizontal displacement meter (10), a temperature sensor (12), a temperature sensor lead (20), a soil sample model (21), a counterforce device (22), data acquisition equipment and a computer, the pressure sensor (1) is arranged on the pressure rod (2), the soil sample model (21) is arranged in the shear apparatus main body, the temperature sensor (12) is arranged in a soil sample model (21), the dynamometer (6) and the temperature sensor lead wire (20) are both arranged on a horizontal rod of a counterforce device (22), one end of the temperature sensor lead wire (20) is connected with the temperature sensor (12), and the other end of the temperature sensor lead (20) is led out through a sensor lead hole and is connected with data acquisition equipment, and the data acquisition equipment is in signal connection with a computer.
2. The shear apparatus for a freeze-thaw cycle shear test according to claim 1, wherein the insulation layer (5) is wrapped outside the upper shear box (7) and the lower shear box (8).
3. The shear apparatus for a freeze-thaw cycle shear test according to claim 1, wherein the insulation layer (5) is made of an insulation material with a thickness of 20 mm.
4. A shear gauge for a freeze-thaw cycle shear test according to claim 1, wherein the first cold liquid inlet pipe (3), the first cold liquid outlet pipe (4), the second cold liquid inlet pipe (13) and the second cold liquid outlet pipe (14) are all in communication with an external cold bath device.
5. The shear apparatus for a freeze-thaw cycle shear test according to claim 1, wherein the temperature sensor lead (20) is led out of the upper shear box (7) and the lower shear box (8), and then the sensor lead hole is sealed by using a heat insulating material.
6. Shear gauge for a freeze-thaw cycling shear test according to claim 1, characterized in that the counter force device (22) is mounted on top of the boss.
7. An experimental method for a freeze-thaw cycling shear test, characterized in that a shear apparatus for a freeze-thaw cycling shear test according to any one of claims 1-6 is used, comprising the steps of:
(1) according to the test scheme, a prepared soil sample model (21) is placed in an experiment shearing box consisting of an upper shearing box (7) and a lower shearing box (8), meanwhile, temperature sensors (12) are arranged at the test point positions, the upper shearing box (7) and the lower shearing box (8) are wrapped by heat-insulating materials, and a heat-insulating layer (5) is formed around the experiment shearing box;
(2) the temperature sensor (12) is connected through a temperature sensor lead (20) and then led out of a sensor lead hole of the experiment shearing box to be connected with data acquisition equipment;
(3) vertically connecting a pressure rod (2) to the center of an upper permeable stone (11), installing a pressure sensor (1) on the pressure rod (2), and installing a horizontal displacement meter (10) and a dynamometer (6) on a horizontal rod of a counterforce device (22);
(4) connecting a first cold liquid inlet pipe (3), a first cold liquid outlet pipe (4), a second cold liquid inlet pipe (13) and a second cold liquid outlet pipe (14) with external cold bath equipment, and switching on a power supply;
(5) and after the test is started, the external cold bath equipment is started to perform cold bath, refrigerating fluid enters the external cold bath equipment through the first cold fluid inlet pipe (3) and the second cold fluid inlet pipe (13) respectively, and returns to the external cold bath equipment through the first cold fluid outlet pipe (4) and the second cold fluid outlet pipe (14) after circulating for a week, so that the soil sample is subjected to a shear test.
8. The experimental method for a freeze-thaw cycling shear test according to claim 7, wherein in the step (5), during the shear test, the data acquisition device performs data acquisition at an interval of once every 10min, and the acquired data is analyzed by the computer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202111467495.5A CN114428024A (en) | 2021-12-03 | 2021-12-03 | Shear apparatus for freeze-thaw cycle shear test and test method |
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| CN202111467495.5A CN114428024A (en) | 2021-12-03 | 2021-12-03 | Shear apparatus for freeze-thaw cycle shear test and test method |
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