诱导冒落的声发射特性研究

Study on Acoustic Emission Characteristics of Induced Caving

采用RFPA软件,模拟不同应力场、不同节理分布的岩体冒落过程中声发射特征.研究表明:水平节理顶板声发射集中分布于采场上拱角处;竖向节理顶板声发射沿着竖向损伤破坏面和剪切破坏面分布;共轭节理顶板声发射沿着空区与水平面呈45°+φ/2方向,位于节理端部;高应力岩体声发射沿着采场竖墙发生,声发射沿着冒落拱形迹线分布.冒落过程声发射的能量变化分为两个阶段,第一阶段为平稳阶段,第二阶段为突变阶段,结果表明突变阶段的能量变化率为第一阶段的5倍以上时,可作为顶板冒落的判据,为工程预测塌陷及冒落提供指导.

The acoustic emission （AE） characteristics during caving process of rock mass under different geo-stress field and joint distribution were simulated by using RFPA software. It demonstrates that the AE in horizontally jointed roof is concentrated in upper arch corner of stope,and the AE in vertically jointed roof is distributed along the vertical damage surface and shear failure surface. The AE in roof with conjugated joints locates at the joint end along the45°＋φ/2direction between mined out area and horizontal plane. For the highly stressed rock mass, the AE is distributed along line of caving arch. The AE energy change during the caving process can be divided into two stages, i.e. the first stationary stage and the second catastrophic stage. This result manifests that the energy release rate during the catastrophic stage of AE release is above 5 times of the first stationary stage, which could provide guidance on engineering to predict collapse and caving.