剪切方向与锚杆倾向垂直条件下锚杆的锚固机制研究  

Study on anchoring mechanism of shear direction perpendicular to rock bolt inclination

作　　者：黎海滨 谭捍华 袁维 黄启舒 韩振中 王华 彭澍[3] Li Haibin;Tan Hanhua;Yuan Wei;Huang Qishu;Han Zhenzhong;Wang Hua;Peng Shu(School of Civil Engineering,Shijiazhuang Tiedao University,050043,Shijiazhuang,China;Guizhou Province Quality and Safety Traffic Engineering Monitoring and Inspection Center Co.,Ltd.,550000,Guiyang,China;China Railway 18th Bureau Group Co.Ltd.,300222,Tianjin,China)

机构地区：[1]石家庄铁道大学土木工程学院,石家庄050043 [2]贵州省质安交通工程监控检测中心有限责任公司,贵阳550000 [3]中铁十八局集团有限公司,天津300222

出　　处：《应用力学学报》2021年第5期1995-2003,共9页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金青年科学基金项目(51709176);河北省自然科学基金优秀青年基金项目(E2021210041);河北省自然科学基金青年科学基金项目(E2018210046);贵州省科技支撑计划(黔科合支撑[2019]2883);河北省教育厅重点项目(ZD2020333)。

摘　　要：为了探究剪切方向与锚杆倾向垂直条件下锚杆的锚固机制,基于经典梁理论,假定锚杆受"拉-剪"联合作用,锚杆受压侧岩体作用反力沿锚杆方向呈抛物线分布,建立了剪切方向与锚杆倾向垂直的力学分析模型。综合考虑锚杆的轴向变形、挠曲变形、位移变分、变形协调关系以及临界锚固状态,得出了锚杆抗剪力计算公式。分析了锚杆产生扭转变形的原因,通过公式推导得出了相对扭转角与锚杆倾角的关系式以及临界锚固状态时扭矩的表达式。通过直剪试验验证了力学分析模型的可行性,并分析了锚杆内力对锚固效应的贡献。结果表明:试验实测抗剪力符合锚杆抗剪力计算公式,锚杆剪切变形与力学模型吻合较好且存在扭转变形;锚杆倾角越大,抗剪效果越好;锚杆抗剪力主要来自剪力的贡献,随着锚杆倾角的增大,轴力对抗剪的贡献比逐渐增大,剪力对抗剪的贡献比逐渐减小。In order to explore the anchoring mechanism under the condition of vertical shear direction and rock bolt inclination,based on the classical beam theory,it was assumed that the rock bolt was subject to the joint action of"tension-shear",and the reaction force of the rock mass on the compression side of the rock bolt was parabola distribution along the bolt direction,a mechanical analysis model of shear direction perpendicular to rock bolt inclination was established.Considering the axial deformation,deflection deformation,displacement variation,deformation coordination and critical anchorage state,the shear resistance formula of anchor was obtained.The cause of torsion deformation of anchor rod was analyzed,the relation between relative twist angle and roc bolt inclination was deduced by formula and expression of torque in critical anchorage state.Through the direct shear test,the feasibility of the mechanical analysis model was verified,and the contribution of the internal force of the rock bolt to the anchoring effect was analyzed.The results show that the measured shear resistance conforms to the calculation formula of the shear resistance of the rock bolt,the shear deformation of the rock bolt is in good agreement with the mechanical model and there is torsional deformation;the larger the inclination angle of rock bolt,the better the shear resistance;the shear resistance of the rock bolt mainly comes from the contribution of the shear,with the increase of the inclination angle of the rock bolt and the structural surface,the contribution ratio of the axial force to the shear increases gradually,the contribution ratio of the shear decreases gradually,and the shear resistance of the rock bolt mainly comes from the"pin effect".

关 键 词：锚杆 力学模型 抗剪力 扭转变形 直剪试验 贡献比 

分 类 号：TU457[建筑科学—岩土工程]