桥桩施工对邻近已运营地铁隧道的实测分析

Analysis on the Influence of Test Pile Construction on Adjacent Existing Metro Tunnels

基于全套管全回转钻孔灌注桥桩施工时对地铁隧道变形和隧道管片病害的监测与调查,综合分析桥桩施工过程已运营杭州地铁1号线隧道的水平位移、道床沉降和水平收敛及桩身周围深层土体水平位移的变化规律。结果表明:(1)邻近既有隧道的桩基施工时采用全套管钻孔灌注桩施工对地铁影响较小,满足地铁隧道安全保护要求;(2)隧道竖向位移、隧道收敛变形、隧道水平位移变化主要与试桩位置、隧道净距、试桩工艺、取土方式和土质情况有关。(3)桥桩施工时,上层土体位移较大,对埋深较浅的道床沉降产生较大的影响,而深层土体位移较小,对埋深较大的隧道影响较小.

Based on the monitoring and investigation of the deformation of metro tunnels and the defects of tunnel segments during the construction of full-casing rotary bored piles,the horizontal displacement,the settlement and horizontal convergence of track bed and the horizontal displacement of deep soil around the pile body of Hangzhou Metro Line 1 tunnel have been comprehensively analyzed during the construction of test piles.The results show that:(1)during the construction of pile foundation adjacent to the existing tunnel,the construction of the full-pipe bored pile has less impact on the metro and meets the requirements of metro tunnel safety protection;(2)The vertical displacement,convergence deformation and horizontal displacement of the tunnel are mainly related to the location of the test pile,the net distance of the tunnel,the technology of the test pile,the way of taking soil and the soil condition;(3)During the construction of the full pipe cast in place bored pile,the displacement of the upper soil body is larger,which has a greater influence on the settlement of the shallow buried roadbed,while the displacement of the deep soil body is smaller,which has less influence on the tunnel with larger depth.