Prediction of Rock Burst Risk in Deep Shaft Excavation of Xincheng Gold Mine

摘要

Core samples at 6 levels below-930m in the new shaft of Xincheng Gold Mine were collected in this case study,and eight evaluation indexes were selected in terms of lithology condition,stress condition and rock condition.It was adopted the entropy method and the technique for order preference by similarity to ideal solution(TOPSIS method)to establish a multi-index rock burst comprehensive prediction model.The stress and elastic strain energy distribution of surrounding rock after shaft excavation were analyzed by using numerical simulation method.Combined with the triaxial test results and the seismology theory,the rock burst risk after shaft excavation was analyzed from the perspective of energy.The results show that:(1)rock burst risk doesn't increase linearly with depth,but is the result of many factors such as rock property,rock mass integrity,in-situ stress environment and energy accumulation caused by excavation;(2)the shaft excavation in deep of Xincheng Gold Mine has strong rock burst risk,it is necessary to take monitoring and pressure relief measures;it is suggested to change the traditional technology"short excavation height and short support height"and adopted the method of flexible yieldable support to control rock burst.