Abstract：It is not always reasonable that the distributing shape of earth pressure in the back of retaining wall is triangular along the height of the wall on the basis of the Rankine and Mohr-Coulomb theories. The distribution of earth pressure presents different curve shapes with different displacements and its form of the wall. The friction between the back of the wall and the filling plays an important role in earth pressure distribution. It is assumed that potential sliding surface of the soil in the back of the retaining wall is composed of logarithmic spiral arc and line. Based on the limit equilibrium of the soils¢ thin-layer elements in the back of retaining wall，calculation formula of the active earth pressure for the clayey soils is suggested. Complex simulated annealing (CSA) calculation method with better searching properties is attained by introducing complex method into simple simulated annealing method to search for local optimization solution. And it is used for searching for the potential sliding surface of the filling and computing the corresponding active earth pressure. Two case studies are given to verify the proposed method. The active earth pressures calculated by the presented method are more close to the in-situ ones comparing to traditional Rankine¢s and Mohr-Coulomb¢s theories.
