For coal mines,rock,coal,and rock bolt are the critical constituent materials for surrounding rock in the underground engineering.The stability of the“rock-coal-bolt”(RCB)composite system is affected by the structur...For coal mines,rock,coal,and rock bolt are the critical constituent materials for surrounding rock in the underground engineering.The stability of the“rock-coal-bolt”(RCB)composite system is affected by the structure and fracture of the coal-rock mass.More rock bolts installed on the rock,more complex condition of the engineering stress environment will be(tensile-shear composite stress is principal).In this paper,experimental analysis and theoretical verification were performed on the RCB composite system with different angles.The results revealed that the failure of the rock-coal(RC)composite specimen was caused by tensile and shear cracks.After anchoring,the reinforcement body formed inside the composite system limits the area where the crack could occur in the specimen.Specifically,shearing damage occurred only around the bolt,and the stress-strain curve presented a better post-peak mechanical property.The mechanical mechanism of the bolt under the combined action of tension and shear stress was analyzed.Additionally,a rock-coal-bolt tensile-shear mechanical(RCBTSM)model was established.The relationship(similar to the exponential function)between the bolt tensile-shear stress and the angle was obtained.Moreover,the influences of the dilatancy angle and bolt diameter of the RCB composite system were also considered and analyzed.Most of the bolts are subjected to the tensile-shearing action in the post-peak stage.The implications of these results for engineering practice indicated that the bolts of the RCB composite system should be prevented from entering the limit shearing state early.展开更多
为研究波纹钢板纵向接缝高强度螺栓连接承载力,建立ABAQUS有限元模型,探讨了端距、螺栓预拉力、波形对波纹板连接件承载力的影响.结果表明:为保证板件端部不被剪断,波纹板连接件的端距应不小于3 d 0;当波纹板连接件发生孔壁承压破坏时,...为研究波纹钢板纵向接缝高强度螺栓连接承载力,建立ABAQUS有限元模型,探讨了端距、螺栓预拉力、波形对波纹板连接件承载力的影响.结果表明:为保证板件端部不被剪断,波纹板连接件的端距应不小于3 d 0;当波纹板连接件发生孔壁承压破坏时,承载力随预拉力的增加而增加,承载力计算公式建议按中国平板连接计算公式乘以1.1的增大系数考虑;当发生螺杆剪切破坏时,预拉力对承载力影响较小,波纹板连接件承载力按平板连接计算公式计算.展开更多
基金Beijing Outstanding Young Scientist Program(BJJWZYJH01201911413037)the projects supported by National Natural Science Foundation of China(Grants Nos.41877257,51622404,and 51974117)Shaanxi Coal Group Key Project(2018SMHKJ-A-J-03)。
文摘For coal mines,rock,coal,and rock bolt are the critical constituent materials for surrounding rock in the underground engineering.The stability of the“rock-coal-bolt”(RCB)composite system is affected by the structure and fracture of the coal-rock mass.More rock bolts installed on the rock,more complex condition of the engineering stress environment will be(tensile-shear composite stress is principal).In this paper,experimental analysis and theoretical verification were performed on the RCB composite system with different angles.The results revealed that the failure of the rock-coal(RC)composite specimen was caused by tensile and shear cracks.After anchoring,the reinforcement body formed inside the composite system limits the area where the crack could occur in the specimen.Specifically,shearing damage occurred only around the bolt,and the stress-strain curve presented a better post-peak mechanical property.The mechanical mechanism of the bolt under the combined action of tension and shear stress was analyzed.Additionally,a rock-coal-bolt tensile-shear mechanical(RCBTSM)model was established.The relationship(similar to the exponential function)between the bolt tensile-shear stress and the angle was obtained.Moreover,the influences of the dilatancy angle and bolt diameter of the RCB composite system were also considered and analyzed.Most of the bolts are subjected to the tensile-shearing action in the post-peak stage.The implications of these results for engineering practice indicated that the bolts of the RCB composite system should be prevented from entering the limit shearing state early.
文摘为研究波纹钢板纵向接缝高强度螺栓连接承载力,建立ABAQUS有限元模型,探讨了端距、螺栓预拉力、波形对波纹板连接件承载力的影响.结果表明:为保证板件端部不被剪断,波纹板连接件的端距应不小于3 d 0;当波纹板连接件发生孔壁承压破坏时,承载力随预拉力的增加而增加,承载力计算公式建议按中国平板连接计算公式乘以1.1的增大系数考虑;当发生螺杆剪切破坏时,预拉力对承载力影响较小,波纹板连接件承载力按平板连接计算公式计算.
