In-situ shearing experimental instrument for measuring saturated loess-mud rock contact surface

Abstract

The invention relates to an in-situ shearing experimental instrument for measuring a saturated loess-mud rock contact surface. A lower shearing box is mounted in an experiment foundation pit, an upper shearing box is mounted on the lower shearing box, and a horizontal hydraulic jack is horizontally arranged between the upper shearing box and the experimental foundation pit; a shearing box pressure cover is mounted on the top of the upper shearing box, the shearing box pressure cover is connected to a counterweight supporting plate through an axial hydraulic jack, and a counterweight is mounted on the counterweight supporting plate; a water holder is also mounted in the experimental foundation pit through a supporting rod of the water holder, and the water holder is connected to a water inlet hole in the upper portion of the upper shearing box through a water delivery pipe, so that injected water flows out from the lower portion of the upper shearing box. The in-situ shearing experimental instrument provided by the invention can truly reflect and keep an excessively wet, saturated and soft and plastic state of the loess-mud rock contact surface in situ without disturbance on soil. A test sample for the experiment is large in dimension, and the in-situ shearing experimental instrument is an effective instrument for acquiring in-situ instantaneous shearing strength and long-term creep shearing strength parameters of heterogeneous soil on the saturated loess-mud rock contact surface.

Description

technical field [0001] The invention relates to the technical field of in-situ testing, in particular to an in-situ shear tester for measuring the contact surface of saturated loess-mudstone. Background technique [0002] The in-situ shear test is actually to measure the shear strength of the rock-soil body itself when the rock-soil body moves along the weak surface or the contact surface under the action of external force; measure the shear strength of the test object under different axial pressures, and obtain the soil strength. The shear strength index cohesion c and friction angle ψ can calculate the stability of geological bodies such as landslides. [0003] At present, in situ shear experiments are mostly experiments on the same rock and soil, such as pure loess, pure gravel soil, etc. For the "loess-mudstone contact surface" landslides that are widely developed in Northwest China, there are few studies on loess and mudstone. The in-situ shear experiment under the sat...

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Problems solved by technology

[0003] At present, in situ shear experiments are mostly experiments on the same rock and soil, such as pure loess, pure gravel soil, etc. For the "loess-mudstone contact surface" landslides that are widely developed in Northwest China, there are few studies on loess and mudstone. The in-situ shear experiment under the saturated state between the contact surfaces shows that the reason why this kind of loess-mudstone contact surface can cause disasters is that there is a large difference in water permeability between the upper and lower contact surfaces. The water permeability of loess is much greater than that of mudstone. After infiltration, it gathers at the rock-soil contact surface, making the loess on the contact surface saturated by water and staying in a state of over-saturated soft plastic for a long time, reducing the strength of the loess

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