Shear-Flow Coupled Behavior of Artificial Joints with Sawtooth Asperities

Abstract

The coupling between hydraulic and mechanical processes in rock joints has significantly influenced the properties and applications of rock mass in many engineering fields. In this study, a series of regular shear tests and shear-flow coupled tests were conducted on artificial joints with sawtooth asperities. Shear deformation, strength, and seepage properties were comprehensively analyzed to reveal the influence of joint roughness, normal stress, and seepage pressure on shear-flow coupled behavior. The results indicate that the shear failure mode, which can be divided into sliding and cutting, is dominated by joint roughness and affected by the other two factors under certain conditions. The seepage process makes a negative impact on shear strength as a result of the mutual reinforcing of offsetting and softening effects. The evolution of hydraulic aperture during the shear-flow coupled tests embodies a consistent pattern of four stages: shear contraction, shear dilation, re-contraction, and stability. The permeability of joint sample is considerably enlarged with the increase of joint roughness, but decreases with the addition of normal stress.

Research on Deformation and Fracture Characteristics of the Fractured Rock Mass Under Coupling of Heavy Rainfall Infiltration and Mining Unloading

“…For rock brittle materials, not only tensile failure but also shear failure affects the growth of cracks. The crack tip will also have N stress perpendicular to the crack surface (Zhao et al, 2012;Cheng and Zhou, 2015;Wei et al, 2017;Zhao et al, 2018;Guo et al, 2019;Liu et al, 2019;Li H. F et al, 2021;Wang and Zhao, 2021). Therefore, it is necessary to focus on studying the law of crack propagation after crack initiation.…”

Permeability Evolution of Fractured Rock Subjected to Cyclic Axial Load Conditions

“…Their results indicated that the permeability increases fast at the beginning of shear deformation, and then the growth continues at a lower rate until to the limit value. Olsson and Barton [20], Shi et al [21], and Zhao et al [22] adopted osmotic pressure to conduct shear-flow coupling test on rock fracture, and empirical formulas regarding the effect of contact area and surface roughness on fluid flow behavior were established. Zhang et al [23] investigated the shear-induced permeability evolution in saw-cut sandstone fractures under triaxial stress condition.…”