Earth Pressure Against Rigid Retaining Wall Of Different Movement Modes

The determination of the magnitude and distribution of earth pressure against rigid retaining wall is important in the design of civil engineering. Classical earth pressure theories such as Coulomb and Rankine earth pressure theory have been widely used to design the retaining structures, because they are simple and can reflect the mechanical concepts clearly. But the classical theories are only valid for the backfill of translation wall arrives the limiting condition, and assumed the earth pressure distribution to be hydrostatic. But the retaining structures in service usually accept some restrains and may subject to move different from translation. The measured earth pressures on retaining wall are mostly non-linear. So, it's necessary to propose a method for evaluating earth pressure considering the mode and the magnitude of wall movement, and it's important to decide the rationality and economy of the retaining wall design.The study objection of the thesis is the rigid retaining wall whose back is vertical and the wall subjects to move outward and away from the backfill in different modes. The destination of the study is to investigate earth pressure against the wall. To the retaining wall moves leaving the backfill, the different wall movement modes including three kinds of basic modes-Translation(T), Rotation about base(RB), Rotation about top(RT) and two combinational modes-Rotation about the point below base (RBT), Rotation about the point above top(RTT). In the paper, it was defined the inter-mediate active state from the rest state to the active state as "the quasi-active state". Based on the model tests and numerical analyses that researchers ever did, the progressive rupture mechanisms of different wall movement modes were improved. Under different modes, with the movement increased, the trend of failure zone development in backfill is different. It's the pattern of the failure zone spreading in soil which determines the mobilization of the soil shear resistance and the friction on the wall-soil interface, and that determined earth pressure against wall, so the relationships between the wall movement and the mobilized angles of soil internal friction and wall friction were developed, to reflect the influence of the wall movement magnitude on earth pressure. Considering the progressive rupture mechanisms in backfill of different movement modes, the modified Coulomb's solutions of active earth pressure were used to calculate the lateral earth pressures, the total lateral forces and their applied points. Comparisons of the calculated results with observations from model tests show that the prdposed methods can provide good predictions of earth pressures for different wall movement modes.The proposed methods of earth pressure calculation considered the wall movement mode and the movement magnitude. They can calculate the earth pressure of each movement magnitude, and they can avoid getting lower earth pressure using Coulomb's solution that will lead to decrease the safety of the structures in design. So, the proposed methods can make the design of the retaining wall safer and more reasonable.