Abstract
The effects of disconnected joints on the mechanical characteristics of rock masses are interesting and challenging aspects of rock mechanics. The prime objective of this study is to investigate the effect of joint orientations and joint connectivity rates on the strength, deformation, and failure mechanisms of rock specimens under unloading condition. To establish the relationships between different factors (confining pressure, joint orientation, and joint connectivity) and failure mechanisms, a series of triaxial unloading tests were performed. The results showed that the joint orientation had a more considerable effect than the joint connectivity on the strength and deformation of the specimens. Generally, three different types of failures were observed (i.e., shear, mixed, and split). Finally, Griffith’s theory was utilized to analyze the maximum tensile stress around the crack. The findings of this paper can also be used for practical engineering problems.
Highlights
Rough the analysis of the deformation modulus of the specimens with different dip angles and connectivity ratios, the variation of different types of deformation modulus with unloading is shown in Figure 5. e deformation modulus is represented as E50, and Δσ3 is the reduction percentage of the confining pressure. e results show that the deformation modulus of specimens with different connectivity ratios is similar under the same confining pressure level
It can be concluded that the confining pressures ranging from 0 MPa to 10 MPa have a little effect on the deformation modulus
The crack propagation was studied on the specimens with partially cut-through joints. e prime objective of this study was to examine the effect of joint orientations and joint connectivity rates on the mechanical characteristics of specimens
Summary
Understanding the mechanical behavior of jointed rock is very important for stratum stability in gas and oil engineering [1]. e stress release and redistribution around the excavation surface generally results in deformation of rock mass together with expansion and extension of existed discontinuities and development of macroscopic fractures.e discontinuities (such as joints, fissures, faults, cleavages, and bedding planes) can significantly affect the mechanical behavior of jointed rock mass [2, 3].Several attempts [4,5,6] have been made in the past to investigate the influence of fractures on the macroscopic behavior of the rock mass and to illustrate the crack propagation mechanisms.Practically, it is too difficult to find a homogeneous rock with a single discontinuity. erefore, researchers have used rock-like materials to investigate the effects of cracks on the mechanical properties of rock masses. Several attempts [4,5,6] have been made in the past to investigate the influence of fractures on the macroscopic behavior of the rock mass and to illustrate the crack propagation mechanisms. Cao et al [7] conducted a series of uniaxial compression tests on similar materials to simulate the effect of preexisting joints and fissures of rock. Meng and Liu [11] used RFPA software to simulate the relationship between a rock mass with one discontinuity and different confining pressures. According to their result, the crack was Advances in Materials Science and Engineering extended vertically at low confining pressure and traced a horizontal trend at a high confining pressure
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
