基于串联流变模型的锚拉力松弛分析方法  

Analysis method for relaxation effect of prestressed anchor cable tension based on a series rheological model

作　　者：邓益 肖世国[2] DENG Yi;XIAO Shiguo(Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Key Laboratory of High-speed Railway Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China)

机构地区：[1]西南交通大学地球科学与环境工程学院,四川成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031

出　　处：《水文地质工程地质》2023年第5期68-79,共12页Hydrogeology & Engineering Geology

基　　金：四川省交通运输科技项目(2020-A-01);国家自然科学基金项目(51578466)。

摘　　要：加固坡体的预应力锚索结构存在锚索拉力随时间松弛问题,为了合理预测分析锚索拉力松弛,基于锚索-边坡体系中滑床、锚索、滑体、坡面抑制构件之间的相互作用与锚固系统受力、变形基本机理,建立了一种采用虎克体模拟锚索或坡面抑制构件、开尔文体模拟滑床、开尔文体或广义开尔文体模拟土质或岩质滑体的锚索-滑床-滑体-坡面抑制件的四体串联式流变模型,推导了锚索拉力松弛的计算方程。实例分析表明:所提出模型的锚索拉力松弛计算值与试验或实测结果的误差小于既有模型的计算误差,计算得到的锚索拉力松弛收敛值的最大计算误差约为11%,松弛历时的最大误差约为10%;锚索拉力松弛率随锚索的直径和弹性模量的增大呈线性增大,随锚孔间距、滑床和滑体的滞后弹性模量与黏滞系数(尤其初期阶段)的增大呈非线性减弱,而滑床和滑体的瞬时弹性模量、坡面抑制构件的弹性模量均对锚索松弛效应影响很小。所建立的方法可用于定量评估预测预应力锚索加固坡体的锚拉力松弛效应,进而可用于分析锚固边坡长期稳定性。Anchor cable tension relaxation with time is a typical problem in the prestressed anchor cable structure used to reinforce slopes.In order to reasonably predict the tension relaxation of anchor cable,based on the interaction among the stable layer,anchor cable,slide mass and constraint components on the slope face in the anchor cable-slope system and the basic loading and deformation mechanism of the anchorage system,a four-body series rheological model composed of anchor cable,slide bed,slide body,and constraint components is established,in which the anchor cable and constraint components are simulated with Hooke body,the slide mass is simulated with Kelvin body or generalized Kelvin body,and the stable layer is simulated with generalized Kelvin body.The calculation equation of the anchor cable tension relaxation is accordingly derived.Some examples show that the error between the proposed value of cable tension relaxation and the observed results is smaller than those using the existing calculation methods.The maximum error of cable tension relaxation convergence value using the proposed method is about 11%,and the maximum error of the relaxation duration is about 10%.The relaxation rate of the anchor cable tension increases linearly with the diameter and elastic modulus of the anchor cable,and decreases nonlinearly with the increasing anchor hole spacing,the hysteresis elastic modulus and the viscosity coefficient(particularly in the initial stage)of the stable layer and slide mass.The instantaneous elastic modulus of the stable layer and the slide mass as well as the elastic modulus of the constraint components have little effect on the tension relaxation of the anchor cable.The proposed method can be used to quantitatively evaluate the anchor tension relaxation of slopes reinforced with prestressed anchor cables in practical engineering,which naturally allows to analyze the long-term stability of the anchored slopes.

关 键 词：边坡 预应力锚索 锚索拉力 松弛效应 串联流变模型 

分 类 号：TU443[建筑科学—岩土工程]