Experimental Study On The Friction And Distribution Characteristics Of The Side Wall Of The Super Deep And Large Sinking

In deep-buried tunnels,hard and brittle rock masses are prone to slab cracking under high ground stress conditions,forming plate-like tunnel surrounding rock.The further damage of the surrounding rock of the plate-like tunnel poses a severe challenge to the safe construction of the tunnel project.In order to study the deformation characteristics and mechanism of brittle fractured surrounding rock or near-vertical layered surrounding rock under the action of in-situ stress,this paper is based on the establishment of a series of structural models of the surrounding rock-slab fracture group of straight-wall tunnel.Theoretical analysis and numerical analysis methods have been carried out to study the deformation and failure mechanism of the sidewall cracking group and its influencing factors.The conclusions are as follows:(1)Obtain the deflection curve equation,the rotation angle equation and the bending moment equation of the straight edge cracked plate of the surrounding rock wall of the tunnel after the cracking of the plate by mechanical derivation;(2)The influences of the influence factors such as the lateral pressure coefficient ?,the vertical ground stress ?_v,the surrounding rock fissure water pressure ?_w and the sidewall cracking plate,the thickness of the cracked plate and the elastic modulus on the deformation of the surrounding rock of the tunnel are discussed.(3)FLAC3D is used to analyze the deformation characteristics of the surrounding rock of the fractured tunnel under various influencing factors,and the influence of vertical geostress and elastic modulus on the deformation trend of surrounding rock.(4)The instability criterion of plate cracking surrounding rock of single-layer split plate is obtained by tension strength condition,compressive strength condition and shear strength condition.