Soil-structure interaction for braced excavation with sloping bedrock
Teo, Xin Lei
Date of Issue2016-05-16
School of Civil and Environmental Engineering
Braced excavation system is a complex soil-structure interaction structure that is commonly used as the supporting system for deep excavation project. The stability of the complicated system will be influenced by various design parameters. Understanding the nature and magnitude of the effects are essential so that the excavation could be constructed safely. Two-dimensional finite element analysis using geotechnical software Plaxis 2D is carried out to study the influence of different design parameters including inclination of the bedrock layer, excavation width, ground water table level, types of soil profile and soil type on the maximum wall deflection, maximum strut force and maximum bending moment developed in retaining wall. It is found that with all the combinations of different parameters, the excavation responses to the changes of each parameter are different. The performance of excavation system is found to be better with a sloping bedrock. However, the effects are significant only if the rock slope angle is large. The effects of sloping bedrock are more significant for thicker GVI soil layer. When the slope of bedrock is steep, the effect of lowering ground water level to reduce maximum lateral wall displacement remains unchanged. On the other hand, the effect of lowering ground water level in reducing maximum bending moment in wall and maximum strut force increases with the increase of rock slope angle. When rock slope angle increases, the percentage increase in value of maximum wall deflection by increasing excavation width declines whereas for maximum bending moment, the percentage increase becomes larger.
Final Year Project (FYP)
Nanyang Technological University