深水环境中两种围堰结构受力特征与经济效益对比分析

Comparative Analysis of Mechanical Characteristics and Economic Benefits of Two Types of Cofferdams Used in Deep Water

围堰是桥墩基坑开挖过程中不可或缺的挡水结构,但其各异的结构形式使选取适合深水环境的围堰结构变得困难。本文以某跨淮河大桥18#墩承台基坑项目为背景,通过建立三维有限元模型对比分析锁扣钢管桩和双壁钢围堰在施工过程中的受力变形特性,结合现场调研对比两者经济效益。结果表明:在高渗透性土深水环境中2类围堰均能满足受力变形要求,而锁扣钢管桩围堰的受力、变形指标均优于双壁钢围堰;锁扣钢管桩围堰的施工成本低于双壁钢围堰。

The cofferdam is an indispensable water retaining structure in the pit excavation process of pier foundations.However,its different structural forms make it difficult to select a suitable cofferdam structure for the deep-water environment.Based on the foundation pit excavation project of 18#pier cap of a bridge across the Huaihe River,this paper establishes a three-dimensional finite element model to compare and analyze the stress and deformation characteristics of locking steel pipe pile cofferdam and double-wall steel cofferdam in the construction process,and compares their economic benefits based on field investigation.The results show that in the deep-water environment of high-permeability soil,both types of cofferdams can meet the stress and deformation requirements,and the stress and deformation indexes of locking steel pipe pile cofferdam are better than those of double-wall steel cofferdams.The construction cost of a locking steel pipe pile cofferdam is less than that of a double-wall steel cofferdam.