الفهرس | Only 14 pages are availabe for public view |
Abstract Implementation of subway systems became one of the effective solutions to overcome some of the enviromental problems which face man’s life sepecially in large highly populated cities. Construction of subway stations and tunnels using the cut-and- cover terhnique empIoy mg reinforced concrete diaphragm walls is considered one of the most effective methods for controlling ground movements wi th minor effects on the adjacent existing structures. Analysis of such braced walls is considered one of the most sophisticated soil-structure interaction problems. This research proposes a numerical modelling for analysis of diaphragm walls during the different construction stages of tunnels and subway stations. The associated variations in the soil stress field and deformations were investigated. In order to carry out such analysis, a computer program was specially upgraded using the Fortran language. Eight-node isoparametric finite elements were used to simulate the soil continuum and the diaphragm wall, the nonlinear stress-strain behaviour of the soil employing modified Duncan model (1984) were utilized. Spring type interface elements were also introduced to model the soil-diaphragm wall contact surface. This thesis presents a comparative study between results of the nonlinear finite element analysis and the field measurements which had been compiled during construction of the Greater Cairo Underground Metro, Phase 1. Also, results of the analysis were compared with the predicted values from the commonly used empirical design rules of such walls. An extensive parametric study was also carried out to evaluate the sensi tivity of the utilized numerical model and the effect of different factors concerning the soil-wall interaction on the behaviour of the diaphragm wall and the associated soil deformations and stress field. |