Back analysis of displacements of excavation involves the coupling of numerical model and optimization method

which is computationally intensive and inconvenient. This paper proposes a multiple response surface method (MRSM) for back analyzing displacements of excavation. MRSM uses quadratic polynomial to express the implicit relationship between the horizontal displacements of the underground diaphragm wall and the soil elasticity modulus at different depths of the underground diaphragm wall of the excavation; and based on that

the back analysis of the elastic modulus of the excavation is undergone with the displacement observation. This method uncouples the numerical model and optimization method so as to attain a higher calculating efficiency. Using spreadsheets makes computational process more convenient. This method is utilized in the back analysis of two excavation cases. We can get convergence result by only three-step iteration in case 1. The predicted trend of the horizontal displacement of underground diaphragm wall is coincided with practical data. The predicted depth of the maximum horizontal displacement approaches the actual measurement. Engineering application cases prove that the MRSM is reliable in displacement back analysis in excavation construction with its features of convenience

high calculating efficiency and accuracy.