水平注浆对既有盾构隧道横向变形与内力的纠偏控制效果研究

Horizontal grouting on the control effect of lateral deformation and internal force of shield tunnel

为探究水平注浆对既有隧道的纠偏控制效果和受力变形规律,建立注浆对既有隧道作用的计算模型,利用非均匀膨胀模型计算注浆引起的既有隧道周围附加应力,根据隧道围压重分布理论推导既有隧道的围压变化。以基坑开挖工程结合注浆工程为算例,计算既有隧道在各个阶段下的围压变化,并根据数值软件建立三环管片模型,得到注浆对既有隧道横向收敛、混凝土应力以及螺栓应力的影响,最后对注浆量、注浆距离以及注浆范围进行参数分析。研究结果表明:水平注浆作用会引起既有隧道围压重分布,其作用在隧道上的附加围压主要呈现为“横椭圆”分布,本案例下隧道两侧腰部的围压复原率达到40%,隧道的收敛及内力复原率均达到了50%。随着注浆量的不断增大,横向收敛及内力均线性增大。随着注浆距离的减小,横向收敛和内力呈现指数型线性增大。单一改变注浆量和注浆距离均可使隧道的变形和内力恢复至正常状态,可考虑首要改变注浆距离以节约资源。注浆效果对注浆深度的敏感性远不及注浆量和注浆距离,注浆深度的改变较小时,注浆效果无明显差异。通过分析隧道复原率可确定注浆工程的参数设置,研究成果可为注浆纠偏邻近既有隧道工程提供参考。

In order to explore the correction control effect and force deformation law of horizontal grouting on existing tunnels.A calculation model of grouting action on the existing tunnel was established,and the additional stress around the existing tunnel caused by grouting was calculated by using the non-uniform expansion model.Moreover,the confining pressure change of the existing tunnel according to the theory of tunnel confinement redistribution was derived.By taking the excavation project of the foundation pit combined with the grouting engineering as an example,the confining pressure changes of the existing tunnel in each stage were calculated.According to the three-ring segment model established by the numerical software,the influence of grouting on the lateral convergence,concrete stress,and bolt stress of the existing tunnel was obtained.Finally,we analyzed the parameter analysis of the grouting amount,grouting distance,and grouting range.The results show that the horizontal grouting effect causes the weight distribution of the existing tunnel surrounding pressure,and the additional confining pressure on the tunnel mainly appears as a“horizontal ellipse”distribution.In this case,the recovery rate of confining pressure on both sides of the tunnel waist reaches 40%,and the convergence and internal force recovery rate of the tunnel reach 50%.With the continuous increase of grouting,the lateral convergence and internal forces increase linearly.Furthermore,with the decrease of grouting distance,lateral convergence and internal forces show an exponential linear increase.The change in the grouting amount and grouting distance can restore the deformation and internal force of the tunnel to a normal state.It can be considered to change the grouting distance first to save resources.The sensitivity of the grouting effect to grouting depth is far less than that of the grouting amount and grouting distance.There is no significant difference in the grouting effect when the change is small.The parameter setting of grouting engineering can be determined by analyzing the recovery rate of the tunnel,and the research results can provide a reference for grouting rectification adjacent to existing tunnel projects.