墙-撑体系在特大深基坑工程中的设计与实践

Design and Practice of Inner Support System for a Diaphragm Wall in Deep Excavation Support

武汉长江I级阶地具有上部软黏土层、下部砂卵石层的二元结构,其基坑围护(特别是深基坑)的设计与施工问题尤为突出。众多特大型深基坑工程的事故表明,对此类工程若未能足够的关注,其潜在的风险将会给工程带来难以弥补的巨大损失。重点讨论深基坑的设计计算方法,并通过一个项目案例来开展研究,采用两种方法来分析支护结构的受力和变形原理:①使用弹性抗力法计算;②使用三维有限元软件建立数值模型模拟分析深基坑开挖过程。根据对支护结构变形的分析,并将计算结果与实际工程监测数据进行比较,以深入了解其变形特征。通过计算结果及监测数据验证其方案的合理性,为类似工程提供指导。

Compared with other areas in Wuhan,the Yangtze River I terrace has a structure with the upper soft clay layer and the lower sandy dual layer.Many geohazards of the super-large deep excavation projects indicate that the potential safety of such projects will result in a huge loss to the projects if they are not paid enough attention to.This paper focuses on the design and the estimation of deep excavation and use a project case history to perform the analysis.Two methods are used to analyze the stress and the deformation principles of the supporting structure:(1)using the elastic resistance method for the estimation;and(2)using the three-dimensional finite element software Geotechnical&Tunnel Analysis System to simulate and analyze the excavation process of the deep excavation.Based on the analysis of the deformation of the supporting structure,several models are used to estimate the deformation,and the results are compared with the actual construction monitoring data.The feasibility of the supporting structure is verified by the analytical results and the monitoring data,which provides guidance for similar projects.