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.
Highlights
The strength and deformability of rock joints have been the subjects of numerous investigations, in design and analysis of underground structures, foundation, slope stability, and risk assessment of underground disposal [1,2,3]
The servo control unit is characterized by rapid speed, high measurement precision, and short feedback time, which can realize the control mode of constant normal load (CNL)
Curvedeformation is a typical sliding failure showing failure mode of shearing can be obtained by analyzing the shear deformation curves
Summary
The strength and deformability of rock joints have been the subjects of numerous investigations, in design and analysis of underground structures, foundation, slope stability, and risk assessment of underground disposal [1,2,3]. The coupling between hydraulic and mechanical processes in rock joints, as one of these subjects, has received wide attention, since a series of events, including dam failures, landslides, and injection-induced earthquakes, were believed to result from it [4,5,6]. Performing laboratory coupled stress-flow tests is an effective way to study the coupled stress-flow characteristics of rock joint [7]. Iwai [8] presented a one-dimensional model where a rough fracture consists of a series of wedge-shaped increments. Raven and Gale [9] studied the effect of changes in sample size on the normal stress-permeability properties of natural fractures. Durham and Bonner [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
