A Study on the Deformation Mechanism of the Rock Surrounding a Weakly Cemented Cross-Layer Roadway, under Tectonic Stress

Maintaining the stability of the surrounding rock is an important prerequisite in ensuring the safe and efficient construction of underground mines-in particular, the surrounding rock of the cross-layer roadway, which is a combination of different media with different lithologies. Numerical models were established to investigate the effects of the different lateral pressure coefficients (lambda), the angle (alpha) between the roadway and the maximum horizontal principal stress, and typical lithological combinations on the deformation of the surrounding rock of weakly cemented roadways. The main outcomes obtained from our research indicated the following: (1) under the action of tectonic stress, the focus should be on strengthening the roof of the roadway support of the slab, which is conducive to the stability of the surrounding rock; (2) roadway deformation and failure for the cases lambda < 1.5 are approximately symmetrically distributed, whereas those for the cases lambda > 1.5 are asymmetric; (3) roadway deformation and failure for the cases alpha < 45 degrees are approximately symmetrically distributed, whereas those for the cases alpha > 45 degrees are asymmetric; (4) tectonic stress has an important influence on stress redistribution, deformability, and damage in cross-layer roadways; and (5) when excavating cross-layer roadways under the action of tectonic stress, the concentrated stress around the end of the working face (especially the bottom corner) should be reduced. The research results provide insights for the roadway layout through coal seam and cross-layer excavation and deepen the understanding of the deformation mechanism of weakly cemented cross-layer roadway under tectonic stress.