A method is proposed to conduct back analysis of the proportional coefficient of horizontal resistance in vertical elastic subgrade beam method for deep excavations according to the measured deformation of retaining wall. The Ucode program is coupled with the Abaqus software in order to achieve this process. This article focuses on the theory and implementation process in the back analysis. Methods for determining the controlling parameters in Ucode program and the parameters to be estimated are also proposed. The soil layer which significantly affects the lateral displacement of retaining wall can be found by parameter sensitivity analysis. Back analysis of the m values for these soil layers can improve both the efficiency of iteration and the accuracy of back analysis results. The methodology is used to analyze an actual project and it is found that the simulated wall displacements is well consistent with the measured ones. According to the back analysis results from several inclinometers

the suitable proportional coefficient of horizontal resistance of each soil layer for this project is obtained.