Effects of Vibration due to Piling in Proximity of MTR Structure and Mitigation Measures

Excavation and Lateral Support (ELS) techniques have been widely adopted in Hong Kong, where limited space and high population density necessitate innovative construction methods. Pile wall installation along the perimeter or within the site area for ELS works serves as common construction practice but invariably generates vibrations. Energy originates from the pile driver would cause the vibration of piles during the driving or installation process. Due to the interaction between pile and the surrounding soils, vibrations are transferred at the interface between pile and soil, and finally propagate through the ground, leading to vibration of ground and existing structures. The primary objective of this technical paper is to present vibration measurements during pile installation for temporary ELS retaining structure as well as permanent foundation and discuss the measures of mitigation for its influence on nearby buildings and MTR structures. It focuses on a specific case of ELS in Hong Kong, providing a detailed study based on actual site records, field experiments, and in-situ documentation of works. Additionally, the paper will draw upon other projects with vibration measurements to summarize the relationship between vibration and distance from the pile installation with consideration of various factors including ground conditions, pile type, ring bit size and piling methods, contributing to a deeper understanding of vibration-induced piling works. The study aims to offer valuable insights and precedents to engineering practitioners and researchers regarding vibration effects and corresponding mitigation measures.