The response of buildings to excavation-induced ground movements.

摘要

Development of infrastructure in congested urban areas is increasing, and excavation-induced ground movement is among the major causes of distortion and damage to adjacent or overlying buildings in open-cut or underground construction. The damage to buildings results in many problems, including impact on third parties, construction delays, and substantial increase of project cost.; This thesis describes a study of building responses to excavation-induced ground movements. The study provides procedures for damage assessment, as well as background for developing guidelines to control building damage due to adjacent excavation.; This study uses field data from case studies, physical model test data from large-scale model tests carried out in the Schnabel laboratory at the University of Illinois at Urbana-Champaign, and numerical parametric studies to investigate the effect of controlled variation of ground and structure parameters. The parameters for the numerical studies include soil stiffness, structure stiffness and strength, number of stories, horizontal ground movement, progressive ground movement, façade wall downdrag, openings, grade beam, roof and floor joist restraint, and brick size. In addition, the response of masonry structures in terms of building distortion is compared with the response of frame structures which are subjected to the same load and ground movement.; The numerical study is performed in two-dimensional plane stress conditions, and a masonry wall is simulated using the Universal Distinct Element Code (UDEC) to capture the complicated behavior of the brick/mortar system. Each masonry block is modeled separately, with contact properties determined by the properties of the brick/mortar interface. With this code, the brick/mortar system can accept large displacement and rotation of brick units as well as progressive cracking and opening of the brick/mortar joint. The ground is modeled as an elastic soil mass with a finite thickness. The soil stiffness in numerical analysis is determined in order to obtain the same pressure/displacement relationship as is found in Boussinesq's equation for a loaded foundation. The numerical study does not include the entire excavation procedure. Instead, ground movement patterns typical of those developed by adjacent excavations, are imposed on the soil mass, and the interactive response between soil and structure is investigated.; This numerical study utilizes controlled variation of parameters to investigate relations among ground movement, building distortion, and damage resulting from adjacent excavation. The investigation includes the effect of relative ground building stiffness on building distortion. In addition, the angular distortion and lateral strain criterion for building damage is evaluated in terms of the state of strain at a point, or the average strain across a building unit.; This thesis includes the results and observations obtained from 1/10 th large-scale model tests at the Schnabel laboratory, the university's large soil model test facility, numerical parametric studies, and field data. This study also reviews the literature on ground movement and building damage and provides background information and materials pertinent to this study.; The results of physical model tests and field observations are combined with the results of parametric studies, and together they are used to provide a background for developing guidelines for controlling building damage and to develop a procedure for estimating building damage due to excavation-induced ground movement. The procedure developed for estimating building damage can be implemented for practical use in the project planning and design stages.