Macro-Micro Mechanical Study on the Shear Behavior of Anchored Joints Under Constant Normal Stiffness Conditions
To investigate the shear characteristics of anchored jointed rock masses in deep underground engineering,this paper conducted direct shear tests on anchored jointed rock masses under constant normal stiffness boundary conditions.The study explored the effects of different joint surface roughness,normal stiffness,and initial normal stress on the shear mechanical properties of anchored joints.The numerical simulation using Particle Flow Code(PFC)was conducted to analyze the macroscopic mechanical characteristics and mesoscopic crack variation characteristics of the anchorage system under the influence of different elastic moduli of bolts.The results indicate that the joint surface roughness significantly affects shear strength,with greater roughness leading to higher shear strength.Anchors can enhance the overall shear strength of the specimens,but normal stiffness and initial normal stress have varying impacts on the anchoring effect and exists an optimal range.The internal cracks of the specimens are mainly tensile cracks.As the elastic modulus of the anchor increases,both the peak shear strength of the anchored system and the number of internal cracks increase at first,then trend to flatten.The shear stress and axial stress curves within the anchor exhibit similar changes and are significantly related to the anchor's elastic modulus.A higher elastic modulus results in more pronounced stress growth,which becomes very slow after reaching the yield strength.
constant normal stiffnessanchored jointed rockdirect shear testmechanical property
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