Study On Stability Of Stope In Deep Mining Under Unloading In Hongtoushan 27# Stope

In recent years, more and more domestic mine have change over to deep underground exploit from superficial part exploit. Along with the degree of depth of exploit increased, the high geo-stress plays more obvious influence in the rock engineering, especially more prominent in turbulent motion to rock mass from the mechanical behaviors which come into being when the mine stope with the method of burst. Special nonlinear mechanical behavior of wall rock is showed in the process of excavation of mine under high geo-stress, which challenges the theory and methods of traditional rock mechanics.For the purpose of meeting the demand of national infrastructure and promoting the development of rock mechanics subject, this paper takes stability of hard rock in the conditions of high geo-stress and brute force unloading as the main theme based on the background engineering of 27# stope in -707 middle piece in hongtoushan in the city of Fushun, in incorporation with the base of research of deep underground mining project in existing metal mine, take monitor to scene with the methods of supersonic wave measure, drill empty camera, multiple position extensometer etc. In cooperation with triaxial compression test and numerical simulation to study the stability of stope wall rock. Summarized speaking, the main work in the paper is finished as following:(1) On the basis of collecting and sorting out related research material about rock mass under high geo-stress in home and abroad, this article summarized the mechanism of deterioration and strength criterion of the rock mass under high geo-stress and the principal influencing factor when the rock wrecked.(2) Triaxial compression test was taken with the test specimen core drilled from hongtoushan, it is indicated that the failure mode of rock from hongtoushan is belong to hard rock brittle break under geo-stress.(3) The data surveyed from work field is comprehensive analysised, rock loose circle and the area of stress concentration can be definited by means of analyzing the outcome of sound waves measurement, drill empty camera, multiple position extensometer and acoustic emission. It can be known from the monitoring results that it make a great distinction between soft rock and hard rock failure and the hard rock only have tidy deformation when it broken down. It is a rigorous problem for field tests.(4) Through the result of numerical simulation and field tests,it is relatively identical, which can proved that the Rock Deterioration Model(RDM) can really reflect the result of hard rock failure.(5) Numerical simulation is taken for the next stope of the mine, then the area of stress concentration and plastic damage area in the wall rock after bursting can be known and some suggestions and protective measures could be taken correspondingly.