The use of protective structures to reduce tunnelling induced damage to buildings

Abstract

Excavation of tunnels in urban areas causes ground movements that could damage existing nearby structures. The interaction between tunnel construction and piled structures has attracted considerable attention from researchers; however the study of protective measures used to reduce the effect of tunnelling on the structures has received less attention. Piled walls are sometimes used in practice to reduce the effect of tunnelling on buildings, however detailed experimental data related to this problem are limited. In this paper, results from three centrifuge tests are presented which aim to quantify the effect of a protective wall in reducing piled structure damage caused by tunnelling. A hybrid testing technique (coupled centrifuge-numerical modelling) is adopted, where a numerical model is used to solve the structural domain (building and foundation loads, including redistribution of loads due to ground movements caused by tunnelling), and the complex non-linear soil, soil-wall interaction, and soil-pile interaction behaviour is modelled within the centrifuge domain. This paper focuses on settlement data obtained from the tests, with results used to demonstrate how the length of the protective wall significantly affects the soil movements on the building side of the wall, with subsequent impacts on pile settlement.