A transient unloading and loosening simulation system for excavation of jointed rock mass under different confining pressures

Abstract

The invention discloses an excavation transient unloading and loosening simulation test system for jointed rock mass under different confining pressures, which includes a reaction pier, a hydraulic station, a loading system, a supporting platform for a loading device, a lever, a lever support, and a transition block , transition block cushion box, test bench with round groove, steel round pipe closed at one end, air compressor, 120° arc-shaped concrete column with displacement scale mark, arc-shaped air bag, jointed rock mass model and monitoring system; , the arc-shaped concrete column and the arc-shaped air bag are used to apply confining pressure to the jointed rock mass, and the loading device is used to apply horizontal pressure to the jointed rock mass. Displacement scale marks are set on the inner diameter of the arc-shaped concrete column and placed in a closed-end The inside of the steel pipe is used to place the jointed rock mass model; the monitoring system is used to monitor the simulation process. The invention can realize fast unloading of the jointed rock mass model under different confining pressures, and make the jointed rock mass model generate larger vibration and strain rate, which is more consistent with unloading conditions in actual engineering.

Description

technical field [0001] The invention belongs to the field of geotechnical engineering model experiment devices, and in particular relates to a transient unloading and loosening simulation system for jointed rock mass excavation under different confining pressures. Background technique [0002] Under the long-term geological tectonic movement and human disturbance, various intricate joints with different directions will be formed in the natural rock mass. However, during the blasting and excavation of deep underground engineering, the transient unloading and stress redistribution of the surrounding rock mass are caused by the excavation disturbance, especially when blasting and excavating in the rock mass containing joints, the jointed rock mass usually appears loosening effect. Blasting excavation will remove all or part of the initial stress on the excavation surface, thereby changing the geometry of the original jointed rock mass, resulting in changes in its boundary cond...

AI Technical Summary

Problems solved by technology

Blasting excavation will remove all or part of the initial stress on the excavation surface, thereby changing the geometry of the original jointed rock mass, resulting in changes in its boundary conditions and load conditions, which may cause serious stability or deformation of the jointed rock mass control puzzle

[0003] However, in the past, the problems related to the transient unloading and loosening of jointed rock mass excavation were studied through theoretical analysis and numerical simulation methods, and the strain during the transient unloading and loosening process of jointed rock mass excavation could not be intuitively understood. , displacement and vibration

However, the existing test system for simulating excavation and unloading has a slow unloading rate, and cannot quickly unload the load on the jointed rock mass model, so the strain rate of the jointed rock mass during unloading is low. Does not conform to the actual unloading situation in the project

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