Abstract
The direct shear test is implemented in this paper for infilled joints under constant normal stiffness (CNS) condition with the finite difference software FLAC3D. The CNS condition was performed based on a servoprogram developed by FISH language. The effects of initial normal stress, undulating angle, and infilled ratio on the shear failure mode of infilled joints under CNS are revealed based on numerical simulation. It is found that the shear strength of infilled joints will grow along with the increase of the undulating angle and the decrease of the infilled ratio. The numerical analysis method is also able to quantify the effect of multiple factors (initial normal stress and infilled ratio) on shear properties of infilled joints. The model shows a good agreement with the experimental results available in the literatures. Therefore, this study proposed and verified a numerical analysis method capable of studying the effects of normal stress, undulating angles, and infilled ratio on the shear behavior of infilled rock joints.
Highlights
With the combined action of tectonics, groundwater movement, and weathering, some joints are filled with soft geologic materials, such as clay and sand. ese soft fillings significantly weaken the shear strength of jointed rock and make the rock present more obvious heterogeneity and anisotropy
The numerical model of the direct shear test is used to study the in uence of di erent factors, including di erent loading conditions (CNS and constant normal load/stress (CNL)), joint undulation, and in lled ratio, on shear properties of rock joints
The direct shear test under constant normal stiffness (CNS) condition for infilled joints was implemented in the numerical method
Summary
With the combined action of tectonics, groundwater movement, and weathering, some joints are filled with soft geologic materials, such as clay and sand. ese soft fillings significantly weaken the shear strength of jointed rock and make the rock present more obvious heterogeneity and anisotropy. Many direct shear tests have been conducted to study the influence of different factors on the shear failure mode of infilled joints. When the joint surface is flat providing little resistance to the movement of filling grain, the shear failure only needs to overcome the rolling friction [9, 10]. Laboratory results from both Ladanyi and Archambault’s [11] and Indraratna’s [12] direct shear tests showed that the increase of joint undulation was able to enhance the shear strength of infilled joints.
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