Testing device for rock three-axis external pressure and hole internal hydraulic pressure coupling loading and unloading

Abstract

The invention discloses a testing device for rock three-axis external pressure and hole internal hydraulic pressure coupling loading and unloading. The testing device is composed of a base, a confining pressure loading and unloading system, a hole internal hydraulic pressure loading and unloading system and an axial pressure loading and unloading system. The confining pressure loading and unloading system comprises a pressure chamber, a confining pressure bag, a protection tire, an oil inlet and outlet channel and a confining pressure electro-hydraulic servo system. The hole internal pressure loading and unloading system comprises an inner pressure bag, an upper sealing member, a lower sealing member, an upper L-shaped elbow, a lower L-shaped elbow, an upper cover plate, a lower cover plate and an internal pressure electro-hydraulic servo system. The axial pressure loading and unloading system comprises a loading block, a piston rod, an oil cylinder, an upper oil cavity channel, a lower oil cavity channel and an axial pressure electro-hydraulic servo system. The testing device is compact in structure, and all functions are independent and collaborative; different non-uniform radial stress fields and different non-uniform tangential stress fields, all of which are distributed in the circumferential direction can be constructed by adjusting the different confining pressure and internal pressure combinations, and linear and nonlinear radial unloading and tangential loading stress paths at points on the non-uniform stress fields in a rock sample can be achieved by adjusting the unloading rate of the internal pressure in a servo mode.

Description

technical field [0001] The invention relates to an indoor rock mechanics test device, in particular to a rock triaxial external pressure and hole hydraulic coupling loading and unloading test device which can realize various stress paths and non-uniform stress field reconstruction. Background technique [0002] With the increasing demand for mineral resources and the continuous consumption of shallow resources due to economic development, more and more mines at home and abroad have entered the state of deep or deeper mining. Deep mining will be the trend and necessity of mining for a long time to come. . In deep hard rock mining, there are some disaster phenomena that cannot be well explained by existing theories and seriously affect engineering construction and efficient resource recovery, such as large extrusion deformation, rockburst, partition rupture, and slab cracking. Studies in recent years have found that these disasters are closely related to the energy transfer a...

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Problems solved by technology

[0004] At present, rock laboratory testing devices that can realize loading and unloading of various stress paths are mainly rock material testing machines, especially rock triaxial testing machines, which can realize loading and unloading of different stress paths in multiple directions, and can simulate local rock blocks in the open state. The mechanical process during the excavation process, but it cannot form a controllable non-uniform stress field in the rock, and cannot simulate the overall unloading response process of the excavated surrounding rock, and it is difficult to achieve strong unloading of various stress paths

The existing hydraulic loading method in the rock hole directly applies the pressure medium such as water to the rock hole wall, and the water is easy to invade into the rock pores or micro-cracks, and even seep out from the rock sample, thereby weakening the mechanical properties of the rock, and the rock and the axial load It is difficult to seal between blocks, and it is difficult to meet the requirements of high-stress hard rock loading and unloading tests

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