关键词: 水力压裂, 采动应力, 巷道变形, 应力转移, 围岩控制

Abstract: The roof of roadway in Guqiao coal mine contained multiple layers of hard key strata, which transferred remote mining induced stress to make the deformation and failure control of the roadway difficult. When hydraulic fracturing technology was used to cut off those roof with multiple layers of key strata to prevent the stress concentration, it was required to fracture the hard key strata accurately and controllably, so as to ensure the effectiveness and safety of the construction. To check the implementability of controllable fracturing, the professional hydraulic fracturing system for rock and coal were employed to carry out tunnel protection filed experiment based on stress transfer through roof cutting. The experimental results showed that the real-time water pressure monitored near the borehole clearly indicate the hydraulic fractures propagation in different rock layers, and can be used as a reference for safety and effectiveness in the construction process. The roof could be effectively cut off layer by layer basing on real-time signal feedback of water pressure and precise fracturing with targeted point borehole sealing. After experimental construction, the displacements of roof and floor as well as side wall were less than 230 millimeters according to the monitored data. The mining induced stress were effectively transferred away and the deformation of the experimental tunnels were effectively controlled. This experiment provided an engineering example of tunnel protection basing on accuracy fracturing roof with multi-layers key strata, and may be referable for those mines with similar tunnel problems.