Combined inversion analysis of coal seam stress field considering joint propagation

Joint propagation changes the physical and mechanical properties of coal due to in-site stress, then the redistribution of coal seam stress and deformation is caused, so the calculation method of coal element joints propagation is given, and relationship between joint propagation and stress is analyzed.Application of wavelet neural network and gradual loading algorithm, a methodology of inversion analysis of coal seam stress field is presented, and the distribution regularity of in-site field is studied for Jincheng block in Qinshui basin using combined inversion algorithm.The results show that the block maximum principal stress increases from northwest to southeast, and it ranges from 8 to 13Mpa; the minimum principal stress is located in Southern Jincheng, and the value is about 5-9MPa.Comparison of combined inversion algorithm results with measured values of the key points indicates that the principal stress relative error is only 3%, and azimuth error is less than 1.3°.So combined inversion analysis has higher calculation accuracy and can satisfy the engineering demand, also it has a series of advantages, such as simple model, fast calculating speed, and so on.