Model Test And Numerical Analysis Of Earth Pressures On Retaining Wall

The determination of forces on structures which are connected to earth mass is of paramount importance in applied Geotechnical Engineering. Classical earth pressure theories enunciated by Coulomb and Rankine have been widely used for the earth pressure analysis and the design of the retaining structures within the validity of the assumptions of these theories. Coulomb and Rankine, however, paid no attention whatsoever to the mode of movement of the wall and assumed the lateral earth pressure distribution to be simply hydrostatic.In this dissertation, model tests and numerical analyses for earth pressure problems of rigid and flexible retaining wall are performed with a view toward an improved understanding of the factors governing the magnitudes and distributions of the earth pressures on retaining wall. So far as rigid retaining wall was concerned, model tests were performed for passive earth pressure acting against a vertical rigid wall, which moved into a mass of dry sand under various wall-movements modes. The types of wall movement includes translation(T), the rotation about a point above the wall top(RTT) and rotation about a point below the wall base(RBT). When considering the wall friction and the mode of wall movement together with the deformation and strength characteristics of soil, finite element computations are performed. Active and passive earth pressure problems are analyzed by using a constitutive model of "Mohr-Coulomb" for soil. A method to describe the factional behavior between soil and wall is proposed using an elastoplastic joint element. The computed variations of earth pressure with wall displacement in active and passive states explain well the influence of the wall friction and the wall movement. The computed distributions of earth pressure where the modes of wall movement are different agree with the tendencies obtained form experimental.So far as flexible retaining wall was concerned, typical example of this class of problem is excavation, the use of finite element method is illustrated. The constitutive model of soil used in this dissertation is hyperbolic considering theinfluence of stress path. The computed results provide a clear picture of the influence of the wall deflection, brace yield, and arching on the magnitude and distributions of the earth pressure on flexible retaining wall in excavation.In addition, based on the research results form rigid and flexible retaining wall, an exponential function is used to describe the relationship between earth pressure and wall displacement. So far as flexible retaining wall in excavation was concerned, It is applied to an improved solution for beam on a nonlinear elastic foundation. The results of example problems indicate that the method presented in this dissertation is more valid and economical than the traditional one.