盾构隧道施工对既有建筑物基桩影响的数值模拟

摘要

As for the common shield excavation technique in subway,the influence of shield excavation on piles foundation was estimated with the simulation calculation for construction process by taking into account the disturb-ance of the excavation face,the pressure of soil chamber,the friction and grouting layer between the shield and the soil.The results indicate that the affecting area of surface subsidence caused by shield excavation is approximately from 20m in front of foundation piles to 25m behind the excavation face in the direction of tunnel axis.The pile ad-ditional axial force induced by the shield excavation increases with the increase of buried depth and reaches the maximum in the depth of the tunnel.However,the moment of pile increases because of the shield excavation, which grows continually with the reduced distance between excavation face and pile.The moment perpendicular to the tunnel axis direction approaches to the maximum value when excavating to the pile position.%针对地铁隧道常用的盾构开挖方式，在考虑开挖面扰动、土仓压力、盾壳与土层间的摩擦力以及注浆层对地表沉降影响的基础上，对盾构隧道的施工过程进行数值模拟，研究盾构隧道开挖对邻近基桩的影响规律。结果表明：在隧道轴线方向，盾构开挖对基桩的影响范围大约为基桩前方20 m至后方25 m；盾构开挖引起的桩身附加轴力随着埋深的增加而增大，在隧道埋深处达到最大值；盾构开挖引起的基桩弯矩随着开挖面与基桩间距离的减小而逐渐增大，开挖至基桩位置时，垂直于隧道轴线方向的弯矩达到最大值。