Predicting Wall Displacements for Excavations with Cross Walls in Soft Clay

Abstract

Cross walls are commonly used in some Asian countries like Japan and Taiwan for constraining the excavation-induced ground settlements as well as mitigating the subsequent building damages. To quantify the effect of cross walls, 22 case histories, including 11 excavations with cross walls and 11 excavations without cross walls, are collected in this study. It is found that cross walls can effectively reduce ground settlements by minimizing wall displacements—the maximum wall displacements for cases with cross walls are within 0.1%He-0.35%He (He=excavation depth), compared with those for cases without cross walls being within 0.3%He-0.8%He. Case histories show that the spacing of cross walls has a major effect on wall displacements. A physical model is proposed to predict the system stiffness in the presence of cross walls. Based on the data points in the collected case histories and the proposed stiffness model, a regression model that is capable of predicting maximum wall displacements is further developed. This model is applicable to cases with or without cross walls and is found to perform reasonably well over independent validation case histories.