深基坑双排桩支护留土开挖优化设计

Optimal Design on Reserved Soil Excavation of Deep Foundation Pits Supported by Double-row Piles

在深基坑支护设计时采用留土开挖的方法,能有效地降低支护结构的内力和位移,节省工程造价。该文以武汉凯德广场古田项目深基坑为工程背景,利用有限元软件MIDAS GTS对不同开挖深度,不同留土高度、宽度的双排桩开挖支护进行模拟对比分析。结果表明:随着留土的高度和宽度的增加,双排桩的内力和位移显著减小;留土高度的变化对双排桩内力和位移的影响大于留土宽度的影响;当留土宽度增大到0.5倍开挖深度后,继续增大留土宽度对双排桩的影响很小;留土对坑底土体隆起位移的影响较小。研究成果可为深基坑双排桩支护留土开挖优化设计提供依据。

In the design of deep foundation pit support, the excavation method of reserved soil can effectively reduce the internal force and displacement of the supporting structure and save the project cost. In this paper, based on the deep foundation pit of Kaide Square project in Gutian, Wuhan, the finite element software MIDAS GTS is used to simulate the excavation of deep foundation pits with different excavation depth and different height and width of reserved soil. The results show that with the increase of the height and width of reserved soil, the internal force and displacement of double-row piles decrease significantly. The influence of the height of reserved soil on the internal force and displacement of double-row piles is greater than that of the width of reserved soil. When the width of reserved soil increases to 0.5 times of the excavation depth, the influence by increasing the width of reserved soil on double-row piles is negligible. The reserved soil has little impact on the uplift displacement at the bottom of the pit. The research results can provide the basis for the optimal design of reserved soil excavation of deep foundation pits supported by double-row piles.