Study on Shear Strength Parameters of Deep Rock Mass in the Naozhong Fracture Zone

Fracture zones typically exhibit weak lithology and fragmented structures, making their shear strength a critical parameter in engineering construction. Determining the shear strength parameters of deeply buried fractured rock masses remains a significant challenge. For the cataclastic schistose rock within the Naozhong fracture zone at the Zala Hydropower Station, in-situ direct shear tests and acoustic wave velocity measurements were conducted both in surface test pits and within an underground deep monitoring tunnel, yielding extensive data on shear strength and acoustic wave velocities. Considering the influence of geological and environmental conditions, the shear strength parameters for the deep fractured rock mass were proposed based on the results of in-situ direct shear tests from the trial pit. Further research revealed a positive linear correlation between the shear strength parameters of the cataclastic schistose rock mass and the acoustic wave velocity. Consequently, a method was established to conveniently obtain the shear strength parameters of deep fracture zone rock masses through surface in-situ direct shear tests and borehole acoustic wave logging, offering a new approach to addressing this challenging problem.