Observed Performance of Diaphragm Wall Construction

Abstract

This study presents the behavior of ground movement induced by the construction of diaphragm wall based on the results of full-scale field tests or panel tests in the construction of the Taipei mass rapid transit system. Two typical test results are presented to understand the general characteristics of ground movement induced by the construction of one wall panel and multiple wall panels. Moreover, the panel test results from the other contracts are also summarized. Results show that the ground settlements after the completion of the whole diaphragm wall construction were much larger than those measured from panel tests because ground movement during the “normal” construction was heavily affected by construction factors. Use of panel test results to evaluate ground settlements might result in a misleading conclusion. Use of the envelope, as established in this study, was a rational way to evaluate ground settlements at the present stage. Besides, the maximum ground settlement of panel tests occurred was about 0.05~0.07 times the trench depth (D) percent and the primary settlement influence zone fell within a normal distance of 0.6D from the panel. The maximum ground settlement after the completion of the whole diaphragm wall construction was about 0.13D(%). The ground settlement beyond 1.5D ~ 2D was found to be insignificant.