硫酸盐侵蚀作用下隧道衬砌时变力学行为研究  

Time-dependent mechanical behavior of tunnel linings under sulfate attack

作　　者：何文正 徐林生[1] HE Wen-zheng;XU Lin-sheng(College of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;College of Urban Construction Engineering,Chongqing Radio&Television University,Chongqing 401520,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]重庆广播电视大学城市建设工程学院,重庆401520

出　　处：《岩土工程学报》2021年第6期1010-1018,I0005,共10页Chinese Journal of Geotechnical Engineering

基　　金：重庆市自然科学基金面上项目(cstc2020jcyj-msxmX0963);重庆市教育委员会科学技术研究计划青年项目(KJQN201904004);山区公路水运交通地质减灾重庆市高校市级重点实验室开放基金项目(kfxm2018-08)。

摘　　要：隧道钢筋混凝土衬砌在硫酸盐侵蚀作用下将发生化学–力学耦合作用,导致其力学性能退化,其退化规律受多方面因素的影响。为了揭示硫酸盐地层中的隧道衬砌在多因素耦合作用下的宏观力学性能退化时变规律,提出了一种硫酸盐侵蚀混凝土的化学–力学全过程分析模型。模型以改进后的硫酸根离子扩散–反应方程组为基础,结合荷载对混凝土孔隙率的影响规律和荷载–钙矾石生长共同作用下的体应变变化规律,计算了混凝土的无量纲损伤参数,以此建立了硫酸盐侵蚀作用下的钢筋混凝土衬砌承载力演变模型,并用试验数据对提出的模型进行了验证。研究结果表明,硫酸盐侵蚀将显著降低钢筋混凝土衬砌的承载能力,受侵蚀的衬砌更容易发生大偏心破坏。该研究成果构建了硫酸根离子扩散–反应过程与隧道衬砌宏观力学性能演化之间的桥梁关系,可以为硫酸盐地层隧道结构的耐久性评估提供参考。The chemical-mechanical coupling effect of tunnel lining concrete under sulfate attack will lead to the degradation of its mechanical properties,and the degradation law is affected by many factors.A chemical–mechanical coupling method for accurately evaluating the time-dependent mechanical behavior of tunnel linings under sulfate attack is proposed.The improved diffusion-reaction equations for sulfate ions are obtained on the basis of the diffusion–reaction approach in combination with the mechanism of volume expansion under a sulfate attack and the influence of load on the concrete voidage.The constitutive response and damage parameters of concrete are calculated according to the volumetric strain caused by the external load and ettringite growth.Then,the evolution model for the bearing capacity of reinforced concrete linings under sulfate attack is established.A case study is conducted to analyze the degradation laws of strength of concrete and bearing capacity of linings obtained using the proposed method.The results demonstrate that the sulfate corrosion will significantly reduce the bearing capacity of the reinforced concrete linings,and the eroded lining is more prone to large eccentric damage.The proposed method serves as a reference for evaluating the durability of an underground structure in a sulfate formation.

关 键 词：硫酸盐侵蚀 隧道衬砌 损伤 耦合 

分 类 号：U451[建筑科学—桥梁与隧道工程]