Study on Roof Caving Mechanism and Grouting Reinforcement Control Method of Weakly Cemented Soft Rock Roadway: A Case Study

Abstract Due to the particularity of the roof lithology, weakly cemented soft rock roadways in western China are prone to roof subsidence and even roof collapse. To solve this challenge, this manuscript combines theoretical research, numerical simulation, and field measurements. First, it proposes the characteristic of overall roof collapse in weak cementation soft rock roadways and introduces a collapse instability mechanism involving "delamination between the top coal and roof strata, fracture outside the support range, and overall roof subsidence." Second, it highlights the characteristics of weak cementation soft rock and the main influencing factors of roof collapse, which include the failure of anchoring due to the roadway exceeding the design width. Finally, based on the characteristics of surrounding rock, a control method for weak cementation soft rock roadways is proposed, combining the adjustment of anchor rod (cable) length with combined deep-shallow grouting. The field application has achieved significant results, effectively controlling the roof subsidence of the roadway.