隧道衬砌结构三轴压缩蠕变特性试验研究

使用MTS-815液压伺服系统对隧道衬砌的混凝土试件进行了三轴压缩蠕变试验，当压缩蠕变强度达到混凝土试件抗压强度的85%时进入加速蠕变阶段。分析了隧道衬砌混凝土三轴压缩蠕变变形的特点，确定采用摩尔-库仑准则和Burgers模型串联组合而成的黏弹塑性模型可以合理地描述衬砌混凝土的蠕变特性。组合模型的黏弹性状态与Burgers模型一致，塑性状态与Mohr-Coulomb模型一致，它不仅能够反映衬砌结构蠕变的全过程，且能模拟材料的黏弹塑性变形特性，解决了典型Burgers蠕变模型只能描述黏弹性蠕变的缺陷。同时也研究了三轴试验条件下组合蠕变模型参数的求解方法，得到隧道衬砌混凝土的蠕变参数。

Experimental studies of triaxial compression creep characters of tunnel lining structure

The triaxial compression creep test on concrete specimens of tunnel lining structure is performed by the MTS-815 hydraulic servo system.The stage of accelerating creep appears when the ratio of compression creep strength to compressive strength is about 0.85.A combined viscoelastic plasticity model is developed after the characteristics of concrete creep deformation were analyzed,which can be used to describe the creep behavior and whole creep process of the tunnel lining structure.The combined model is characterized by a visco-elastoplastic deviatoric behavior and an elastoplastic volumetric behavior.The viscoelastic constitutive law corresponds to the Burger model,and the plastic constitutive law corresponds to a Mohr-Coulomb model.The characteristics of viscoelastic plasticity can be described by the combined model.The problem which the typical Burgers model only can be used to describe viscoelasticity creep is resolved perfectly.In addition,the methods to solve triaxial compression creep model parameters are given and the parameters of tunnel lining structure are determined.