全长黏结锚杆特征荷载试验研究  

Study on Characteristics Load Test of Fully Bonding Anchor Bolt

作　　者：江冠 冯忠居[2] 赵瑞欣 王富春 王思琦 JIANG Guan;FENG Zhong-ju;ZHAO Rui-xin;WANG Fu-chun;WANG Si-qi(School of Urban and Rural Planning and Architectural Engineering,Shangluo University,Shangluo Shaanxi 726000,China;School of Highway,Chang’an University,Xi’an Shaanxi 710064,China)

机构地区：[1]商洛学院城乡规划与建筑工程学院,陕西商洛726000 [2]长安大学公路学院,陕西西安710064

出　　处：《公路交通科技》2023年第9期45-53,共9页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(41272285);国家重点研发计划项目(2018YFC1504801)。

摘　　要：为评价高速公路边坡既有锚杆的锚固效果,依托京沪高速公路改扩建边坡工程,对边坡既有全长黏结锚杆进行了现场拉拔破坏试验。通过现场实测荷载-位移增量曲线确定了支护锚杆的工作荷载和极限荷载,建立了锚杆拉拔数值仿真模型,研究了全长黏结性锚杆-注浆体、锚固体-岩层两界面剪应力的分布规律。结果表明:荷载-位移增量曲线呈现“增大-减小-缓增-陡增”的变化特征;锚杆在拉拔荷载作用下经历外锚固段紧固阶段、锚杆-注浆体耦合变形阶段、塑性变形阶段、脱黏阶段等4个阶段,其中锚杆-注浆体耦合变形阶段与塑性变形阶段、脱黏阶段分别对应既有全长黏结锚杆工作荷载、极限荷载;锚杆工作荷载主要发生在锚杆-注浆体耦合变形阶段与塑性变形阶段区间,为区间拉拔荷载中值;锚杆极限荷载以位移增量陡增特征点为依据,为单级位移增量5 mm左右对应的拉拔荷载;当锚杆处于工作荷载阶段时,锚杆-注浆体界面、锚固体-岩层两界面的剪应力沿埋深方向均呈单调递减的分布形式;当锚杆达到极限荷载时,锚杆-注浆体界面、锚固体-岩层界面的剪应力分布形式由“单调递减”转变为“单峰分布”,且随着拉拔荷载的增加,剪应力峰值向深部移动。In order to evaluate the anchoring effect of the existing anchor bolts on expressway slopes,relying on the G2 Beijing-Shanghai expressway slope reconstruction and expansion project,the field pull-out failure test on the existing fully bonding anchor bolts on the slope is carried out.The workload and ultimate load of fully bounding bolts are determined according to the curve of load vs.displacemental increment.The numerical simulation model for pull-out test on the bolt is established,and the distributions of shear stresses at the interface between fully bonding anchor bolt and grouting and the interface between anchorage and rock stratum are studied.The result shows that(1)the curve of load vs.displacemental increment exhibits a variation characteristic of“increase-decrease-slow increase-steep increase”;(2)the anchor bolt undergoes 4 stages under the action of pulling load,including the tightening stage of external anchoring section,the coupling deformation stage of the anchor bolt-grouting,the plastic deformation stage and the debonding stage,among which the coupling deformation stage of the anchor bolt-grouting(and the plastic deformation stage)and the debonding stage correspond to the working load and ultimate load of the fully bonding anchor bolt respectively;(3)the working load of the bolt is occurred in the interval between the coupling deformation stage of the anchor bolt-grouting and the plastic deformation stage,which is the median value of pull-out load of the interval;(4)the ultimate load of the anchor bolt is based on the characteristic point of steep increase in displacemental increment,which is the pull-out load corresponding to the single level displacemental increment of about 5 mm;(5)when the anchor bolt is in the working load stage,the shear stresses at the interfaces between the anchor bolt and the grouting and the interface between the anchorage and the rock stratum show“monotonic decreasing”along;(6)when the anchor bolt reaches the ultimate load,the distributions of shear stresses at

关 键 词：道路工程 荷载传递机理 拉拔试验 全长黏结锚杆 极限荷载 界面剪应力 

分 类 号：TU473[建筑科学—结构工程]