土钉墙支护基坑对邻近地下管线的影响

Impact on Adjacent Buried Pipelines Caused by Pit Excavation with Soil-nailing Walls

为了研究基坑开挖支护过程对邻近地下管线的影响,在分析土钉墙、管线与土的相互作用以及基坑开挖的数值模拟方法的基础上,建立了三维非线性有限元模型,比较分析了不同的管线与基坑距离、管线埋深、土钉长度、土钉间距和管线周围土体性质下,地下管线位移的分布与变化规律。结果表明:在基坑拐角以外10 m^20 m范围内会出现远离基坑向水平位移,此处水平向曲率变化最大;粉土下水平位移约为砾质黏土下水平位移的4~5倍;随着管线埋深的增大,竖向位移减小,而水平位移增大,在坑底达到最大值;在坑底位置,粉土水平位移约为砾质黏土的10倍;竖向位移最大时,粉土约为砾质黏土的7倍。

In order to study the impact on adjacent buried pipelines during pit excavation and the construction of soil-nailing walls,a three-dimensional nonlinear finite element model was built based on the interaction between soil-nailing wall,pipelines and soil mass. According to the comparison of the simulation results and the on-site measured data,the error was within 15%,which proved the reliability of this model. The main factors influencing the displacement of pipelines were studied including the distance between the pipelines and the pit,buried depth,soil-nail length,spacing and properties of the soil mass. Results indicate that the outward horizontal displacement of the pipelines occurs within the range of 10 m ~ 20 m outside the pit corners which results in a large change of horizontal curvature; the horizontal displacement under silty clay was 4 ~ 5 times larger than that under gravel clay; with the increasing of buried depth,the vertical displacement decreases while the horizontal displacement increases and reaches its largest value at the bottom of the pit where the horizontal displacement of silty clay was 10 times higher than that of gravel clay; the largest vertical displacement of silty clay was 7 times greater than that of gravel clay.