Theoretical And Numerical Study Of Piled-raft

The purpose of this thesis is to highlight the effect of the raft-pile-soil interaction with the stiffness of soil or sand, which is examined by the use of the computer programming Plaxis3D Foundation and staad pro2006for loading calculation. The finite element later is used for the analysis of the raft and pile. The interaction between raft, pile and soil which is the major importance in the behaviors of the piled raft is considered in the analysis. In this4-types of interaction, the interaction between piles plays a important role.Plaxis3D foundation program can be used for analysis in vertical and horizontal loading. The performance of the piled raft is affected by several factor such as the soil properties and condition, pile dimension and its arrangement and raft thickness. Examination of these factors has shown that its effected the displacement if the raft and load carried. It improved the performance of piled raft.Several case simulation is done in this thesis, the solution from Plaxis3D foundation.1)Effect of using number of piles and arrangement of the pile, in this case different number of piles are used and these piles are arranged in different way from each other, the result is effective after the arrangment. It also help to reduce the displacement, moment and shear force.2)Effect of pile diameter and arrangement, in this case the diameter of the pile varies from lm to2m using different arrangement in different case. In this case the result is unexpected that using less number of piles and less diameter it gives the relatively good result. So it can say that only using bigger sized diameter of the pile it cant reduced the displacement and moment and shear force. 3)Effect of pile length, in this case the analysis showed that the only small amount of settlement is reduced after the length of the pile is increased but if the stiffness of the soil is increased then it was effectively reduced in the settlement.4)Thickness of the raft, varies from1m to3m with the constant soil parameter. When the thickness of raft is increased the settlement of the system also reduced but the torsion moment and shear force are vice-versa to each other.5)For the case study of Wuchang, it is taken one simulation from the simulation done and used horizontal beam so that to reduce the effect of bending moment and shear force. After using the beam the displacement is moved toward the edge of the raft.Generally, for the pile foundation in the sandy soil, the piled are distributed longer length at the center of the system and it is gradually reduced its length toward the edge because the load take more at the center and at the edge the load is less as compare with the center. Here, in this case study the length of the all pile are take in same length but it don’t gave the pile at the edge of the raft and it gave the beam in the raft but the settlement is changed. That is, it is shown above in the case and the settlement is moved toward the edge in opposite side like1/4from the edge. The displacement is moved from the center to the edge.