The weak anchoring force and inadequate stability of the anchoring system (AS) in fractured rock roadways frequently lead to anchor rod slip failures. To address this issue observed in a mine in Song County, this study employed a combination of theoretical analysis, laboratory experiments, numerical simulations, and field tests for a comprehensive investigation. Firstly, the study examined the load‐bearing capacity, interactions between backfilling body and surrounding rock, and the force distribution exerted by the backfilling body on the surrounding rock under various bottom backfilling body shapes. The inverted wedge shape was identified as the optimal expansion configuration. Secondly, laboratory pull‐out tests were conducted on anchor rods configured in three different forms. These tests aimed to compare and analyze the variations in anchoring force among the three anchoring configurations, as well as the interactions between backfilling body and surrounding rock. The results indicated that utilizing self‐expanding head anchor rods for bottom backfilling and anchoring support yielded the most significant improvement in anchoring efficacy. Finally, a field test was conducted at a mine in Song County. The findings revealed that the utilization of self‐expanding head anchor rods for bottom backfilling and anchoring support resulted in a transition of the surrounding rock deformation from axial to predominantly transverse. The maximum deformations of the roof, floor, and sidewalls were decreased by about 85%. The time required for the roadway to reach stability was advanced by ~150 days. Further evidence suggests that this anchoring support technology can achieve a significant increase in anchoring force with only a modest increase in engineering investment, thereby effectively ensuring the stability of the roadway.
Wang et al. (Thu,) studied this question.