Ring shear test equipment under soil body freezing and thawing cycle and weathering environment and test method thereof

Abstract

The invention provides ring shear test equipment under a soil body freezing and thawing cycle and a weathering environment and a test method thereof. The equipment comprises a ring shear instrument, freezing and thawing cycle equipment, a data acquisition unit, a sunlight simulation system, a low-temperature cold air system and a computer. The ring shear instrument comprises a counter-force frame,a vertical loading device and a shear box assembly. When the ring shear test equipment works, a soil body is arranged into a shear box and is compacted. The freezing and thawing cycle equipment is used for introducing cold nitrogen into a freezing and thawing chamber and then the soil body is frozen. An oil-pressure chamber is internally and fully filled with hydraulic oil and hydraulic equipmentis used for loading or unloading to push a piston to move up and down, so as to control the volume of cold nitrogen. After frozen soil is prepared, vertical load is applied to the upper part of the soil body through a vertical loading device. A rotary platform rotates to drive a lower shear box to rotate and a torque is applied to the soil body. The test method of the equipment comprises the steps of filling the soil body, carrying out the freezing and thawing cycle, carrying out a ring shear test, processing data and the like. The equipment can be used for effectively simulating on-site frozen soil ring shear. Microscopic characteristics in a test process of a test sample can be observed and the acting time of the freezing and thawing cycle can be controlled.

Description

technical field [0001] The invention relates to the technical field of engineering permafrost science, in particular to a ring shear test device under soil freezing-thawing cycle and weathering environment. Background technique [0002] Frozen soil refers to various rocks and soils with a temperature at or below 0°C and containing ice. Permafrost is extremely temperature sensitive and contains abundant subsurface ice. Therefore, permafrost has rheological properties, and its long-term strength is much lower than the instantaneous strength characteristics. Because of these characteristics, construction of engineering structures in permafrost must face two major dangers: frost heaving and thawing. What plays an important role is the existence form of water. When the water turns into ice, the volume increases, which makes the soil expand, and the surface of the earth is arched and raised, which is frost heaving; when the ice in the soil turns into water, the volume increases....

AI Technical Summary

Problems solved by technology

[0004] In the prior art, there is no on-site freeze-thaw cycle of the soil, and there is no on-site simulation of the combination of the ring shear experiment and the frozen soil

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