本科毕业设计外文 翻译.doc

Section 3 Design philosophy, design method and earth pressures Design philosophy General The design of earth retaining structures requires consideration of the interaction between the ground and the structure. It requires the performance of two sets of calculations: 1)a set of equilibrium calculations to determine the overall proportions and the geometry of the structure necessary to achieve equilibrium under the relevant earth pressures and forces; 2) structural design calculations to determine the size and properties of thestructural sections necessary to resist the bending moments and shear forces determined from the equilibrium calculations. Both sets of calculations are carried out for specific design situations (see ) in accordance with the principles of limit state design. The selected design situations should be sufficiently Severe and varied so as to pass all reasonable conditions which can be foreseen during the period of construction and the life of the retaining wall. Limit state design This code of practice adopts the philosophy of limit state design. This philosophy does not impose upon the designer any special requirements as to the manner in which the safety and stability of the retaining wall may be achieved, whether by overall factors of safety, or partial factors of safety, orby other measures. Limit states (see ) are classified into: a) ultimate limit states (see ); b) serviceability limit states (see ). Typical ultimate limit states are depicted in figure 3. Rupture states which are reached before collapse occurs are, for simplicity, also classified and treated as ultimate limit states. Ultimate limit states include: a) instability of the structure or any hart of it, including supports and foundations, considered asa rigid body; b) failure by rupture of the structure or any part of it, including supports and foundations. Ultimate limit states General The following ultimate limit states should be