Acoustic emission ground stress field testing and mechanism of deformation and instability in deep soft rock roadway

In order to obtain accurate ground stress,deformation and failure law,and instability mechanism in deep soft rock tunnel,the two caverns at the same level in 1 km deep mine were selected for testing acoustic emission technology to gain the value and direction of respective ground stress. The test found that the distribution of vertical stress has a slight difference,and the distribution of horizontal stress had great difference. Based on the theory of in-situ stress cal- culation formula,the corresponding program was written with VB6. 0,for calculating the value and direction of main stress field in corresponding part. Combining with the field drilling histogram,a model was established using ANSYS, and then imported into FLAC3D to make numerical analysis. Therefore,the cavern surrounding rock deformation law and instability mechanism under corresponding main stress field were obtained. It shows that there was larger concen- tration degree and wider distribution of shear stress in weak region,and the destruction of surrounding rock was very serious. Finally,the study found that the field measurement data is in consistent with numerical simulation results. It found that the seriously damaged surrounding rock also has a big convergence rate,which reveals the law of deforma- tion and destruction in deep soft rock roadway and explains that the surrounding rock lithology,the concentration de- gree and the range of shear stress play an important role in the roadway stability.