Settlement characteristics of immersed tunnel of Hong Kong-Zhuhai-Macau Bridge project

Abstract

This paper presents the settlement performance of immersed tunnel in Hong Kong-Zhuhai-Macau Bridge (HZMB) transportation project. The geological profile underlying the immersed tunnel was presented and the corresponding field monitoring system was introduced as well. The function of the semi-rigid element is analyzed. The observed results related to longitudinal deformation patterns during construction, e.g., long-term settlement, differential settlement, and structural behaviors are described and analyzed. The differential settlement happened in the following situations: (a) large variations of soil properties; (b) at the joint of two adjacent elements; (c) different segments of the same element. The differential settlement not only occurred in the longitudinal direction but also in the transverse direction. During the operational period, permanent settlement is strongly related to back-silting. The tide loading and the immersion of adjacent element may cause transient settlement related to the elastic deformation, however, tide loading has less influence on the permanent settlement. Highlights: • The long-term settlement behavior of immersed tunnel of Hong Kong-Zhuhai-Macao Bridge (HZMB) project is presented; • The geological condition and field observational system of immersed tunnel are presented; • The mechanism of macroscopical longitudinal settlement and microscopic differential settlement are explained; • The influencing factors led to various deformation patterns are discussed.