基于多因素耦合效应的锚索预应力长期损失研究  

Study on pre-stress long term loss of anchor cable considering coupled multiple factors

作　　者：冯忠居[1] 江冠 赵瑞欣 龙厚胜 王政斌 张正旭 FENG Zhong-ju;JIANG Guan;ZHAO Rui-xin;LONG Hou-sheng;WANG Zheng-bin;ZHANG Zheng-xu(School of Highway,Chang'an University,Xi'an,Shaanxi 710064,China;Shandong Hi-speed Group,Jinan,Shandong 250014,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]山东高速集团有限公司,山东济南250014

出　　处：《岩土力学》2021年第8期2215-2224,共10页Rock and Soil Mechanics

基　　金：国家重点研发计划项目(No.2018YFC1504801);国家自然科学基金(No.41272285)。

摘　　要：为研究锚索锚固力长期损失规律及计算方法,基于广义胡克定律、松弛率时程响应方程与改进西原锚固耦合本构模型,建立了三因素锚固力损失计算方法,利用三因素损失计算方法分别计算了锚具垫板内滑锁紧、索体钢绞线应力松弛、岩体蠕变耦合的锚索预应力理论损失值。开展锚索拉拔破坏原位试验进一步验证长期损失计算方法的准确性,通过分析拉拔荷载传递机制,确定了荷载-增量位移曲线自由段拉拔阶段为锚索的工作荷载区间,取其区间中值为锚索时效锚固力,并获取了预应力长期损失实测值。研究结果表明:20年运营期锚索预应力损失值约为17.5%~27.5%;岩体蠕变是锚索预应力长期损失的最显著影响因素;三因素损失计算方法理论值与现场预应力损失实测值误差约4.2%,验证了三因素损失计算方法的准确性,表明长期预应力损失的三因素计算方法满足一定精度要求,具有可行性。In order to study the long-term loss law of anchorage force and the calculation method of pre-stress loss of anchorage force,a calculation method of the pre-stress loss of anchorage force was proposed to account for three factors.The proposed method is based on the generalized Hooke’s law,relaxation rate time-history response equation and improved coupling constitutive model.It was adopted to calculate the theoretical loss value of the anchor cable pre-stress coupled with the internal sliding lock of the anchor plate,the stress relaxation of the cable body steel strand,and the rock mass creep,respectively.In order to verify the accuracy of the long-term loss calculation method,the anchor cable pull-out failure test was also carried out.By analyzing the transfer mechanism of the pull-out load,it was determined that the pull-out stage of the free section of the load-incremental displacement curve was the working load interval of the anchor cable.The median value of the working load interval was taken as the effectiveness force of the anchor cable,and the measured value of the long-term loss of prestress was also obtained.Results show that the pre-stress loss of the anchor cable is about 17.5%-27.5%during 20 years.The rock mass creep is the most significant factor affecting the long-term loss of the anchor cable.Besides,there is an error of about 4.2%between the calculated value of the three-factor loss calculation method and the measured value of pre-stress loss at site.This verifies the accuracy of the three-factor loss calculation method,and also shows that the three-factor calculation method of long-term pre-stress loss mentioned here meets accuracy requirements and is feasible.

关 键 词：预应力锚索 预应力损失 原位拉拔试验 锚固力 岩体蠕变 

分 类 号：TU457[建筑科学—岩土工程]