Circulating compression-shear soil frost heaving test system and test method

Abstract

The invention discloses a circulating compression-shear soil frost heaving test system and test method. The test system comprises a temperature control test cabin, a horizontal loading motor, a vertical loading motor, a horizontal displacement sensor, a horizontal force sensor, a vertical displacement sensor, a vertical force sensor, a pore pressure acquisition instrument, a temperature controller, a Markov water replenishing bottle and a power supply. For a test soil unit, the temperature control test chamber adopts a temperature control metal plate to form a temperature control space around a test piece, so that the test is prevented from being influenced by the atmospheric environment on one hand, and on the other hand, a laminated ring with relatively small thickness can be conveniently adopted in the test, and the loading effect of the horizontal cyclic shear stress of the soil unit is improved. The vertical direction and the horizontal direction of the soil body frost heaving test system can be set to be static or dynamic loading, a soil body frost heaving test, a soil body melting test or a soil body freezing and thawing cycle test under temperature-complex stress path coupling can be carried out, and dynamic parameters such as dynamic shear modulus and damping ratio of frozen soil or positive temperature soil can be tested.

Description

technical field [0001] The invention belongs to the technical field of geotechnical tests, and relates to a cyclic compression-shear soil frost heave test system and a test method. Background technique [0002] In geotechnical engineering in cold regions, soil frost heaving has brought many engineering diseases, resulting in more economic losses. Existing studies have shown that soil frost heave is a complex physical process, which is affected by factors such as temperature, moisture, load, and soil quality. For subgrade soil, under the action of moving traffic loads, the stresses borne by subgrade soil units include vertical dynamic compressive stress, horizontal dynamic compressive stress, and horizontal cyclic shear stress. In fact, for the soil under positive temperature, the horizontal cyclic shear stress will bring about the shear dilatation of soil particles, which has a great influence on the deformation of the soil and the pore water pressure inside the soil. In p...

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Problems solved by technology

CN110940598A discloses a multifunctional permafrost cycle single-shear test device and test method, because its shear box adopts the mode of circulating refrigerated liquid to control the side temperature of the test piece, causing the thickness of a single shear box to be too large, which is difficult for fine particles For soil specimens, the applied horizontal shear stress is not uniform inside the soil unit, so it is not suitable for cyclic single shear loading of fine-grained soil

[0004] In summary, it can be seen that the current soil frost heave test system and test methods still have the following deficiencies: (1) Most of the test systems achieve lateral insulation by adding thermal insulation materials on the side of the specimen, but the existence of gaps in reality As a result, the insulation effect is not ideal, and the temperature during the test is still affected by the outside world (2) There is no device for cyclic single-shear heave tests for fine-grained soils, which cannot reflect the impact of horizontal cyclic shear stress components on soil frost heave (3) The current soil frost heaving test system has not yet been able to apply the overlying dynamic compressive stress, horizontal dynamic compressive stress, and horizontal shear stress at the same time, and cannot achieve the effect of the rotation of the principal stress axis of the soil unit during the test

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