Influence of rockbolt pretension on bolting behaviors by gravel bolting tests
Xiaoqing Wang, Jinfu Lou, Jianzhong Li, Fuqiang Gao, Guiyang Yuan
Abstract
The influence of rockbolt pretension on bolting has not been well addressed, despite its critical importance in drift support systems. In this study, laboratory and numerical simulations of gravel bolting are conducted to investigate the effects of varying rockbolt pretensions. The simulations are developed using the particle flow code (PFC3D), enabling detailed analysis of contact forces between gravel particles under low and high rockbolt pretensions. The results indicate that bolted gravel can maintain stability even without pretension, though bearing capacity is significantly enhanced under high pretension. Two distinct bolting behaviors are identified: a pressure arch structure is formed under low pretension, while high pretension creates a compression zone characterized by intensified particle interlocking and superior load-bearing capacity. Based on these findings, a concept for drift support is proposed, integrating rockbolts and cables to stabilize both shallow and deep rocks. This study advances our understanding of bolting behaviors and provides theoretical guidance for designing effective drift support systems in practical applications.