In-situ direct shear tester for soil bodies

Abstract

The invention discloses an in-situ direct shear tester for soil bodies. The in-situ direct shear tester comprises a steel frame, a vertical oil cylinder, a cylinder, a horizontal oil cylinder and a push bowl, wherein the vertical oil cylinder is arranged on the steel frame; the cylinder can be horizontally and movably arranged at the power output end of the vertical oil cylinder; the horizontal oil cylinder is arranged on the steel frame; the push bowl is arranged at the power output end of the horizontal oil cylinder, and used for exerting a horizontal thrust on the cylinder, and enabling the cylinder to move a predetermined distance; and the horizontal oil cylinder is also provided with a displacement sensor for measuring the displacement and a first pressure sensor for measuring the thrust, and the vertical oil cylinder is also provided with a second pressure sensor for measuring the lateral pressure. According to the in-situ direct shear tester, the vertical oil cylinder and the horizontal oil cylinder are adopted for automatically and gradually exerting horizontal and vertical loads, and then the cohesion, internal friction angle standard value and pressure-deformation curve of a soil body are obtained by using a shear test; and the tester is accurate in testing, flexible to operate and reliable in result.

Description

technical field [0001] The invention relates to the technical field of soil in-situ testing, in particular to an in-situ soil shearing test instrument. Background technique [0002] Soil shear strength test values ​​are currently divided into indoor shear experiments, field shear experiments, and cross shear experiments. The basic principles and theoretical basis for determination are the same. The key to the availability of the results lies in the selection of test methods The determination of body shear strength mainly includes direct shear test and in-situ direct shear test. [0003] The direct shear test is a method for measuring the shear strength of soil. The common method is to use 4 samples, respectively, under different vertical pressures, to apply horizontal shear force for shearing, to obtain the shear stress at the time of failure, and then according to Coulomb's law determines the shear strength parameters of soils, internal friction and cohesion. [0004] The...

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Problems solved by technology

[0004] There are three methods of direct shear test: fast shear, consolidation fast shear, and slow shear. Whether it is triaxial shear or conventional direct shear test, it is required to collect undisturbed soil samples on site, and then test them under different pressures, drainage conditions and conditions. The test is carried out under the environment to determine the value of the soil. The indoor direct shear test artificially controls the shear plane, and the drainage conditions are also difficult to control, so that the stress state is quite different from the natural state of the soil. It is difficult to ensure the consistency and uniformity of the soil sample state

[0005] The above-mentioned method also has the weakness of taking soil from local areas, the shear surface of the soil sample is too small, and the result is "point to surface".

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