Roadway Instability Mechanism of Weakly Consolidated Soft Rocks and Support Technologies

During tunneling in weakly consolidated soft rock strata, lithology, joints, and fractures of strata play an important role controlling overall roof stability the roadway. A case study based on roadway Bojianghaizi mine was conducted to address disasters caused by sudden changes collapse as well difficulties maintenance First, physical mechanical properties rocks were investigated X-ray diffraction mineral component analysis scanning electron microscopy. Second, failure characteristics instability mechanism analyzed combining field survey theoretical analysis. model fracture development composite built, initiation angle critical stress for deduced. The criteria cracks cracking ( θ 0 ) established. Moreover, falling disclosed. Fractures formed upon shear at vertex belt extended bedding plane separation stratum along propagation connected with it, thereby inducing falling. On this basis, a high-strength high-preload “inverted trapezoidal” anchoring mesh-beam string supporting structure + arched cross-section vertical walls full-section guniting coupling control technology proposed, which achieved good site application effects.