Research on dynamic stability of large deformation roadway with application of segmented resistance anchor bolt

Abstract

The dynamic stability of large deformation roadway can be significantly affected by seismic vibration. In order to improve the support effect, a segmented constant resistance anchor bolt structure is proposed. The preload can be set in segments to effectively reduce the tension deviation. The support stability of this type of bolt is verified by field test and experimental simulation. Based on the bearing and deformation characteristics of surrounding rock, the supporting and installation, grouting process and anchor cable stress monitoring of this type anchor bolt are designed. Through the field measurement of the roadway, the variation laws of the rock swelling coefficient, anchor cable tension and roof subsidence under the condition of bolt support are obtained. A tunnel dynamic deformation test-bed is built to study the dynamic vibration response of the designed anchor bolt to alternating load. Applying orthogonal exciting force, the tension changes in different constant resistance sections are obtained. The results show that this type of bolt has remarkable effect of resisting alternating load, and the maximum tension deviation within ±200 m working face is less than 8 %, which has better support stability than conventional bolt.