Research On Single Pile Bearing And Reinforcement Technology In A Continued Project

The piled raft foundation has become one of the common forms of high-rise building foundation for the advantages of good entirety, high carrying capacity and less settlement and so on. With the change of the economic situation and macro-control policies, lots of continued projects appear in many areas for some reasons. Before continued projects begin to construct, the carrying capacity and ability to control the settlement of the original foundation need to be reappraised to ensure the suitability of the building. Evaluation contents of piled raft foundation for continued project include single pile bearing capacity and foundation reinforcement technology. Based on practical design of a reinforcement program in Tianjin, the detection scheme of single pile bearing capacity and foundation reinforcement technology is researched in this paper. The principal contents are as follows:Firstly, by comparing the static load tests for the original piles in two stages, the original piles have completed and the continued project will be constructed, the ultimate bearing capacity of existing single pile and the settlement of pile top and pile bottom is provided. What’s more, the quality of original piles is detected to provide evidence for the foundation reinforcement program.Secondly, methods for determining the install location of load-box and the conversion methods from self-balanced results to traditional pile head load-settlement are summarized. The load-box laying position for an engineering design practice is given in using standardized test method and numerical simulation method. The interaction between the upper part of the pile and the lower one is analyzed for the project with FEM.Finally, the three-dimensional finite element models of raft-pile-soil interaction with the use of ABAQUS are established to analyze the influence of supplementary pile length, pile strength and reinforced raft thickness on the bearing and deformation characteristics of the raft and pile foundation. Based on the analysis, the foundation reinforcement program is determined. A comparison between calculated results and field tests on the reaction of piles and raft internal force is conducted.