Effects of the layers of foundation soil on the seismic response of dikes

• Main Author: Leo, Sin Chyuan
• Other Authors: Budi Wibawa
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Civil engineering::Geotechnical
• Online Access: http://hdl.handle.net/10356/63496
• Institution: Nanyang Technological University

This study will describe the effect of different layers of foundation soil on the seismic response of dikes using PLAXIS 2D software. The soil layers will mainly consist of silty sand, dense sand and clay. Each of these soil layers will have a thickness of 5m each and these three layers will be permutated in combinations to achieve the least amount of settlement during a seismic activity. This study will also include a sand dike model of 40m base depth, 10m span across at the top of the dike and a height of 5m. The seismic coefficient for the analysis of this model will be between 0.01g to 0.015g. The water level depth for the analysis will be at 4m, 2m and 0m respectively. A total of 108 combinations of analysis will be done to simulate all possible combinations of seismic coefficient, soil layer and water depth. The standard procedure of this analysis using PLAXIS 2D will be explained in step by step basis with diagrams and instructions. Results obtained will be tabulated in table form and graphs will be plotted by using the data obtained. By comparing all different layer combinations, the most distinctive layer combination would be layer combination 5. This layer has the most settlement during Initial Phase and Dynamic Loading Phase. This is due to the clay layer right being at the bottom of the founding level. The silty sand layer and dense sand layer are most susceptible to liquefaction hence the largest settlement value. Further research analysis insights will be given at the end of the report to improve the current study results.