In-situ investigation on fractured evolution law of surrounding rock in weakly cemented soft rock roadway

Abstract

ABSTRACT Weakly cemented soft rock has a great influence on the deformation and stability of roadway in the process of roadway excavation. There are different requirements for the excavation and support of roadway under such geological conditions. Based on the Hongqingliang Mine geological conditions, the deformation and failure characteristics of surrounding rock such as dry blasting, spalling and over width of roadway are analyzed. Through the on-site monitoring of surrounding rock deformation, bolt (cable) stress, and roof drilling in weakly cemented soft rock roadway, the results show that the deformation and failure of roadway surrounding rock can be divided into fast deformation and slow deformation; the force of bolt increases first and then decreases, finally tends to be stable, while the force of cable increases rapidly and then tends to be stable; at the same time, through the roof borehole detection, the roof fracture concentrates in the range of 3 m of the roof, and with the excavation process proceeding, the mudstone in the deep roof also appears a certain fracture. The breakdown position is about 6 m away from the roof.