Experimental study on shear characteristics of energy-absorbing bolt anchored jointed rock mass under constant normal stiffness condition
To explore the shear characteristic of energy-absorbing-bolt anchored rock joints and corresponding bolt performance under constant normal stiffness(CNS)boundary conditions(the condition is associated with deep buried rock mass engineering).We conducted direct shear tests on energy-absorbing bolted rock-like joints.In particular,the tests were performed under diverse joint roughness coefficient(JRC)and anchorage depth(h)to investigate their influence on the deformation characteristics of anchor bolt and mechanical properties of rock joints,such as shear stress(r),normal displacement(δn),normal stress(σn)and failure characteristics of joint surfaces.The test results revealed that energy-absorbing bolt effectively enhance the yield strength and shear strength of deep rock joints.The improvement degree progressively increases with a higher JRC value,in which the shear stress first undergoes the elastic period,followed by the stress hardening period.Besides,the shear-induced damage area on the joint surface grows with increased JRC,and it grows by 20.88％-109.21％under energy-absorbing bolt anchored conditions.Moreover,an increase in anchorage depth initially leads to an increase in shear stress,normal displacement,normal stress,and the shear-induced damage area of the joint surface,followed by a subsequent decrease.The optimal values for these properties were observed at an anchorage depth of 80 mm,allowing for the full utilization of the anchorage effect during the plastic deformation stage of the anchor bolt.These findings provide significant theoretical support for reducing cost and improving efficiency in the support of deep rock joints.
rock mechanicsjoint roughness coefficientanchorage depthenergy-absorbing boltconstant normal stiffnessshear characteristics
万方数据
维普
