Study on control mechanisms and key parameters of surrounding rock in roadway retention by hard roof cutting

ZOU Jun; XIE Shengrong; YANG Ruizhuo; FANG Xu

doi:10.11799/ce202511007

Abstract：To address the challenges of surrounding rock control in gob-side entry retention under hard roof conditions using the roof-cutting technique,this study employs theoretical analysis,numerical simulation,and engineering practice.A mechanical model for overburden movement in a roof-cutting retained roadway and a numerical model for pressure relief via thick-hard immediate roof cutting were established.The failure mechanism of the surrounding rock was clarified.The effectiveness of advanced pre-split pressure relief under different parameters was compared,the stress response characteristics of the surrounding rock to various roof-cutting parameters were analyzed,and the evolution of stress in the retained roadway surrounding rock with panel retreat was investigated.The results indicate:①The length and state of the lateral cantilever beam in the roof are key factors affecting surrounding rock stability.Roof cutting significantly reduces the roof bending moment,decreasing gob-side roof subsidence to 11.4%of the value observed without cutting.Under conditions of thick-hard roof stratified caving,a support-balanced structure can effectively control roadway deformation,confirming the control approach of coordinated"roof pressure relief and surrounding rock reinforcement."②The stress response to different cutting angles and heights was analyzed.The dynamic evolution of full-process vertical stress and deviatoric stress in the surrounding rock under mining influence was obtained.The stress peak in the solid coal rib shows a steep-then-gentle negative correlation with both cutting angle and height.③A control strategy combining"high-strength roof pressure relief anchoring,deep anchorage of the solid coal rib,and gangue blocking with roof support on the gob side"was proposed.Field application shows that under this coordinated control method,the displacement rate of the retained roadway surrounding rock is low,anchor cable loads remain stable,and surrounding rock control is effective.