盾构隧道同步注浆施工引起的地层变形分析

Analysis of Stratum Deformation Caused by Synchronous Grouting in Shield Tunnel

同步注浆是盾构隧道施工的重要施工工艺,对控制地层变形影响显著。为得到盾构同步注浆施工引起的地层变形理论解析解,将同步注浆浆体在土体中扩散引起的地层位移问题简化为半无限土体中柱孔扩张问题,从无限体中柱孔扩张的基本解答出发,对半无限问题采用地表应力修正的方法,得到弹性条件下半无限体中的挤土位移解。并通过具体工程实例,分析影响同步注浆引起地层变形的因素。结果表明:同步注浆引起的地表隆起值随注浆率线性增长,随隧道开挖半径的增大或开挖深度的减小而增大。

Synchronous grouting is an important construction technology in the construction of shield tunnel, which has significant influence on the deformation of the strata. In order to acquire the strata deformation theory analytic solution caused by shield synchronous grouting construction, the problem of formation displacement caused by the diffusion of synchronous grouting slurry in the soil is simplified as the problem of column expansion in semi-infinite soil.Starting from the basic solution of the expansion of the column in the infinite body,the method of surface stress correction for the semi-infinite problem is used to obtain the squeezing displacement solution in the semi-infinite body under the elastic condition. And then we analyze the factors affecting the formation of synchronous grouting through the specific engineering examples.The results show that the surface uplift caused by synchronous grouting increases linearly with the grouting rate, and increases with the increasing of tunnel excavation radius or the excavation depth.