Settlement due to Diaphragm Wall Construction in Reclaimed Land in Hong Kong

Abstract

For more than two decades diaphragm walling has become commonly used for the construction of deep excavations in Hong Kong. For example, 13 of the main excavations for the Island Line of the Mass Transit Railway (MTR), completed in 1986, adopted diaphragm walls as the principal support to the excavation. Diaphragm walls were particularly appropriate to the MTR construction in over-crowded urban Hong Kong, limiting adverse effects on surrounding buildings and allowing top-down construction methods, thus reducing programming time. Settlement was predicted for buildings on deep foundations (piles), adjacent to deep excavations, and the actual settlement was monitored by conventional surveying techniques. The results indicate that settlement due to diaphragm walling is generally substantial and that preconstruction activities such as ground treatment, drilling, and preboring for wall panels, must be taken into account in any settlement predictions.