顶管泥浆套与混凝土界面剪切力学特性试验研究

Experimental Study on Shear Mechanical Properties of Interface Between Mud Screen of Jacking Pipe and Concrete

为研究顶管注浆后浆土混合体与管道两者之间的相互作用机制,本文共设计了6种不同的浆土配比,利用改进的直剪容器和大型加载剪切仪,对浆土混合体和混凝土接触面在单调荷载作用下的剪切力学特性进行了较系统的试验研究.研究结果表明:浆土混合体-混凝土界面的抗剪强度与试样中触变泥浆的含量呈指数变化形式;随着界面法向应力的增大,界面剪应力-剪切位移曲线由应变软化特性向应变硬化特性转变;触变泥浆在试样剪切过程中对接触界面的剪胀效应起到弱化作用;接触界面的黏聚力和摩擦角随试样中泥浆含量的增多分别呈线性减少和指数减小的变化趋势,得到了考虑泥浆含量的泥浆套-混凝土界面抗剪强度计算公式.

In order to study the interaction mechanism between slurry-soil mixture and pipeline after pipe-jacking grouting,six shear tests of the interfaces with different slurry-soil ratios were designed,the shear mechanical properties of the interface between the slurry-soil mixture and the concrete under monotonic loading condition were systematically studied by using an improved direct shear container and a large shear test device.The results show that the shear strength of the interface between slurry-soil mixture and the concrete varies exponentially with the content of thixotropic mud.As the normal stress of the interface increases,the characteristics of the shear stress-shear displacement curves of the interface changes from strain softening to strain hardening.Thixotropic mud weakens the dilatancy effect of contact interface during the shear process of specimen.With the increases of mud content in the sample,the cohesion and the friction angle of the interface decreased with linear trend and exponential trend,respectively.The shear strength calculation formula of the interface between the mud screen and the concrete was obtained,which consider the mud content.