Experimental device and method for realizing rock shearing under mining-induced stress gradient

Abstract

The invention discloses an experimental device and method for realizing rock shearing under mining-induced stress gradient, and the device is characterized in that a normal loading mechanism is arranged above a roller support, and consists of a normal gradient pressure constructor, a normal loading rod, a normal pressure sensor and a normal displacement sensor; the normal gradient pressure constructor comprises a supporting plate, a loading pressing block, a cover plate and a spring; a plurality of loading pressing blocks are arranged on the supporting plate, a plurality of vertical sliding grooves are formed in the cover plate, and a plurality of springs with different lengths are independently connected to the corresponding vertical sliding grooves and the loading pressing blocks; and the left shear loading mechanism and the right shear loading mechanism are oppositely arranged on the left side and the right side of the test space between the support and the normal gradient pressure constructor. The method comprises the following steps: assembling the experimental device; applying initial pressure; applying mining normal gradient pressure; applying mining lateral pressure; performing a one-way shear test; performing a cyclic shear test; and ending the experiment, and storing and sorting data. According to the device and the method, the shearing mechanical property of the rock in the mining-induced stress environment can be accurately obtained.

Description

technical field [0001] The invention belongs to the technical field of rock mechanics and engineering, and in particular relates to an experimental device and method for realizing rock shearing under a mining stress gradient. Background technique [0002] The strength and deformation characteristics of rock under shear are important geological conditions that affect the safety of oil and gas development, mining, tunnel excavation, and dam construction. Engineering practice shows that after the rock mass is excavated, the stress field of the surrounding rock changes, and the mining stress of the surrounding rock presents a certain gradient distribution in the excavation area. Therefore, it is of great theoretical and engineering value to study the shear mechanical properties of rock under gradient pressure. [0003] The existing shearing experiment device usually fixes the rock in the shearing box to carry out the shearing test, and it is necessary to cut the rock specimen s...

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Problems solved by technology

[0003] The existing shearing experiment device usually fixes the rock in the shearing box to carry out the shearing test, and it is necessary to cut the rock specimen strictly according to the size of the shearing box, so that the surface of the rock specimen and the shearing box fit closely. However, during the shear test, the rock specimen in the shear box still inevitably shakes;

[0004] At this stage, although there are some technical means that can improve the shaking of the rock specimen in the shear box during the experiment, they do not take into account the influence of the gradient distribution pressure on the upper part of the rock specimen, so it is impossible to accurately obtain the rock specimen. Rock shear mechanical properties under the influence of stress

For the normal stress gradient distribution, some test devices are realized by honeycomb oil cylinder and oil distribution circuit control, but the structure of this test device is extremely complicated and the cost is high

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