Deformation And Force Characteristics Analysis On Outrigger-type Diaphragm Wall

In recent years, underground continuous wall with outrigger, a new form of exterior protected construction, can be used as both the retaining structure of foundation pit engineering and the vertical load-bearing structures. As underground continuous wall with the outrigger designed to be flexible in the complex formation, saving cost and many other advantages, it has been applied in a variety of projects already built or under construction. In deep foundation pit engineering, the stress and deformation characteristics of retaining structure also as the vertical load-bearing structures are the most concern in the design and construction. As a novel and more complicated retaining structure than the ordinary, the traditional theories of the stress and deformation characteristics and the vertical load-bearing properties can’t be directly applied to the underground continuous wall with outrigger, especially the deformation problem of leg-side in variable cross-section. These problems greatly limit the promotion and application of this new type of retaining structure. In this paper, using large-scale finite element software of ABAQUS to study underground continuous wall with outrigger as the retaining structure and the vertical bearing structure and its stress and deformation characteristics. The main work is as follows:(1) FEM of the underground continuous wall with outrigger used as retaining structure in deep foundation was established, systematically analysis three aspects of underground continuous wall with outrigger used as retaining structure in the process of deep foundation pit engineering, rear ground surface settlement, upheaval of ground in pit and the typical characteristics of the stress and deformation of continuous wall and outrigger. Study the effects of different leg.s length of underground continuous wall with outrigger on load-carrying and deformation of foundation pit, and sum up some laws to come to the reasonable length of the leg, consequently provide references for the design and construction.(2) FEM of the monolithic underground continuous wall with outrigger used as vertical bearing structure was established, study the bearing behavior of the monolithic underground continuous wall with outrigger in vertical uniformly distributed load. Furtherly analysis parameters of the system, research the influences of the soil properties of the side and deep end of the wall and the leg and the nature of the interface between wall and soil on its vertical bearing properties, and finally sum up vertical load transfer mechanism of underground continuous wall with outrigger.(3) FEM of a typical cross-section of the expansion project of Hangzhou Huanglong Hotel deep foundation was established, and compare the numerical results and monitoring data during the foundation pit excavation, and study the problem of reasonable stiffness of section steel inserted in the leg.