Test device for realizing loading and unloading of different stress paths in rock holes

Abstract

The invention discloses a test device for realizing loading and unloading of different stress paths in rock holes. The test device comprises an electro-hydraulic servo loading / unloading system and an inner-hole loading / unloading executing mechanism, wherein the electro-hydraulic servo loading / unloading system comprises an oil tank, a hydraulic pump station, an electric control pressure adjusting system, a three-position four-way electro-hydraulic directional control valve, a pressurization system, a speed-adjusting unloading system, a high pressure pipeline and a control host machine; the inner-hole loading / unloading executing mechanism is formed by assembling a hydraulic pressure bag, an inner-outer lock, a pressing nut, an L-shaped elbow, a joint, a rigid pressing plate with a U-shaped slot and a supporting block. The test device has a compact structure, is suitable for rock true triaxial and conventional triaxial tester, can be used for loading / unloading central holes of the rock sample, wherein the hole depths are 1 to 1.5 times of the length of the hydraulic pressure bag and the cross sections are circular, oval, square and arc, can be used for realizing the quick uniform loading of multiple stress paths in rock holes and the quick synchronous reconstruction of the stress gradient at each point in the rock sample and also can be used for preventing the hydraulic oil from invading the rock sample and influencing the mechanical property.

Description

Technical field [0001] The invention relates to a rock test device, in particular to a test device that realizes loading and unloading of different stress paths in a rock hole, and is suitable for physically simulating the dynamic response process of deep high-stress hard rock excavation and unloading. Background technique [0002] With the increasing demand for mineral resources in the development of the national economy and the continuous depletion of shallow mineral resources, ore mining and underground chamber excavation have gradually shifted to the deep. Due to the existence of deep high ground stress and strong excavation unloading disturbance, it involves the deformation, failure and instability of the surrounding rock of deep excavation engineering, such as rock burst, zonal fracture, large compression deformation, slab crack and other disasters more and more. The excavation response of shallow rock masses under lower ground stress mainly depends on the shape and size o...

AI Technical Summary

Problems solved by technology

[0003] At present, the indoor rock test devices that can realize loading and unloading of different stress paths are mainly material testing machines based on electro-hydraulic servo systems, especially rock triaxial testing machines, which can realize loading and unloading of different stress paths in multiple directions, but cannot Creates controllable stress gradients within the rock and makes rapid multi-stress path unloading difficult

Existing rock material testing machines can reproduce the mechanical process of local rock blocks in excavated surrounding rocks, but it is difficult to simulate the overall stress redistribution process of surrounding rocks, that is, it is difficult to simultaneously reproduce the unloading stress path and space of rock samples in the time dimension Stress Gradients in Dimensions

The existing hydraulic loading device inside the rock directly contacts the hydraulic medium such as hydraulic oil or water with the inner cavity of the rock. The hydraulic medium easily invades into the pores or cracks of the rock due to high pressure, thereby weakening the mechanical properties of the rock, and the hydraulic medium is easily separated from the rock and the outside. Leakage at the contact surface of the pressure-loaded mechanism is difficult to seal

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