Large Deformation Disaster Mechanism and Control Technique for Deep Roadway in Faulted Zone

Xuewei Liu,Bin Liu,Yong Luo,Juxiang Chen,Yuanguang Zhu,Xing Huang

doi:10.3389/feart.2022.826661

Abstract

In order to study the mechanism and control technique of deep roadways in faulted zones, the 11-2 transport roadway of Guqiao coal mine in Huainan was taken as a case. The research roadway encountered two faults named F97 and F98 and suffered a severe large deformation disaster (including floor heaving, side cracking, steel arch bending, and section shrinkage) after excavation. Then, laboratory tests, in situ stress measurement, and numerical simulation results indicate that the lower strength and easy to soften property of the surrounding rock is an immanent cause, while high geo-stress is an external inducement of large deformation. The continuous behaviors of opening, moving, and rotation of rock blocks under the above factors finally caused large deformation disaster. Finally, a control technique named stages and combination control method (SCCM) has been proposed. This technique contains two steps, namely, primary (including prestressed anchor bolt, shotcrete, and grouting) and secondary (including prestressed cable) support stages. Numerical calculation and in situ monitoring results indicate that the SCCM technique can stop the failure of surrounding rock and control the displacement of the surrounding rock effectively.

Highlights

Coal will remain the mainstay of energy for a certain time in the future
The increased ground stress, broken surrounding rock, mining disturbance, and geologic tectonism could cause a large deformation disaster of the roadway which will threaten the safety of mining
The results show that the softening coefficient of the surrounding rock is about 0.43

Summary

Introduction

Coal will remain the mainstay of energy for a certain time in the future. Recently, more and more coal mines have a mining depth of over 1,000 m all over the world, including Russia, China, Japan, Australia, and so on. The increased ground stress, broken surrounding rock, mining disturbance, and geologic tectonism could cause a large deformation disaster of the roadway which will threaten the safety of mining. The mechanisms for roadway large deformation of surrounding rock are varied.

Results

Conclusion