Seismic barrier for surface waves
Chin, Joy Jia Min
Date of Issue2016-05-24
School of Civil and Environmental Engineering
Unfavourable vibrations induced by dynamic sources can cause negative effects on nearby buildings and sensitive equipment. Most of these vibrations propagate in the form of surface (Rayleigh) waves. Mitigation of these vibrations can be achieved in the form of trench barriers, which works by reducing the unfavourable effects by scattering the waves. An open trench barrier is the most ideal in mitigating vibrations, however due to its instability, in-fill materials are used. Different in-fill materials such as water, concrete, bentonite, EPS geofoam and gas cushions were considered in previous studies. However in this study, RSM (Rubber and Sand mixtures) was the choice of in-fill material. In this project, a field experimental study was conducted to examine the screening performance of the following trench configurations: An open trench and two trenches with different percentages of RSM, namely 70% rubber and 30% rubber by weight. The study further takes into consideration parameters such as trench geometry, location and excitation frequency to investigate how they may impede the screening effectiveness of the barrier. The experimental results were analysed and interpreted to provide the key ideal performance parameters for the usage of trench barriers and the best compositions of RSM as in-fill materials. The field experimental results confirm that the use of open and in-filled trenches may be adopted as an effective mitigation measure for negative ground vibrations due to a stationary wave source (frequency controlled vibrator) in this study.
Final Year Project (FYP)
Nanyang Technological University