Comprehensive analysis of large trapezoidal section workings'stability in broken rock mass

摘要

Ningdong coalfield locates northwest meizoseismal areas. Rock mass in the coalfield is broken, unconsolidated and exists complicated stress zones. Thick seams distributed widely adopt mining method of high seam full extraction. Part Structural failure and phenomenon of strength degradation are often occurred. Based on investigations of in-situ geomechanics, lithology, mining condition and dynamic instability, key sections of deformation and unconsolidation in typical working rock mass is detected by deep point displacement observation method and ultrasonic detection method, and then analyzed the rules of the deformation and instability. According to detection results and the knowledge of theoretical mechanics, multi- medium coupling support project is put forward. Styles and quantitative parameters of rational supports are ensured and estimated for their stability and safety.