NUMERICAL ANALYSIS ON A NEW FOUNDATION SYSTEM WITH COLUMNIFORM SOIL IMPROVEMENT

摘要

The soil must be capable of carrying the loads from any engineered structure placed upon it without a shear failure and with the resulting settlements being tolerable for that structure.To satisfy the geotechnical strength requirements and the serviceability requirements, types of foundation systems (such as shallow foundation, pile foundation and composite foundation) have been developed. Of course, the type of foundation system is determined by many factors such as ground condition, economy and environmental influence of construction. When building on soft ground, bearing pile foundation systems, foundation systems with deep soil improvement, and the piled raft foundation systems together with raft foundation and friction piles are often adopted. However, in many cases, the bearing capacity is overestimated and they become relatively uneconomical by using these foundation systems. To cope with weak or compressible soils, a raft foundation system with partially dented shallow soil improvement has been proposed as an economical environment-friendly foundation system for low/light buildings on soft ground. The effects of the foundation system have been revealed by the measured data of the settlement of the actually constructed structure, and the parametric numerical analyses have been performed before. This thesis presents a new raft foundation system with columniform soil improvement for multistory buildings, which is economical and environment-friendly. In this new raft foundation system, different columniform soil improvements in size and depth are used, and the subgrade under the edge of the foundation is walled by soil improvement. It can effectively control differential settlement and prevent relative rising of the structure by adjusting the size and depth of columniform soil improvements according to the soil layer difference of geological situation under the building. In this paper,numerical analyses are performed under two-dimensional plane strain condition to study the settlement behaviors of the new raft foundation. This paper describes numerical analyses on the rough settlement behavior of the new foundation system.