Rigid Pile Composite Foundation Of High-rise Building Pile Soil Stress Ratio Test And In Situ Analysis

The design and construction of rigid pile composite foundation have been in the stage of relying on the practical experience and qualitative. Two kinds of extreme situation appear. One is thickness of mattress layer of accidents, the other one is the waste of material and the high cost of engineering, then the composite foundation has not played the role. So how to make the rigid pile composite foundation safe, reliable and economy has become a current problem that people need to solve.First of all, this paper describes the development history and present situation of composite foundation and rigid pile composite foundation. Then this paper respectively presents present situation of rigid pile composite foundation on three fronts from the experimental research, theoretical research and numerical simulation.Secondly, based on the introduction of present research situation of rigid pile composite foundation, this paper elaborates the principle of destruction and load transfer characteristics of rigid pile composite foundation, and from the cushion layer, the effective length and area replacement ratio and pile soil stress described separately the performance of rigid pile composite foundation. That lays the foundation for this study.Third, this paper introduces the equipment layout and data collection. Through in-situ test of super high-rise building of the rigid pile composite foundation piles and soil, this paper analyzes the distribution of pile top and soil between piles pressure in each region of rigid pile composite foundation and pile-soil stress ratio and load sharing ratio. The test results in this paper have certain reference value for the similar foundation composite foundation design.Then, in order to verify the rationality and accuracy of the experiment, Taking the pile-soil stress ratio as the research object, this paper establishes the pile-soil deformation coordination equation under certain assumptions to get the calculation formula of pile-soil stress ratio. Put test parameters into the calculation formula and compare it with experimental results. And on this basis, the paper has analyzed the thickness and modulus of cushion to obtain the optimal design of parameters for cushion of the rigid pile composite foundation.Finally, this article uses the finite element software MIDS/GTS to establish the three-dimensional model of rigid pile composite foundation, and research the changes of pile and soil’s stress when length and spacing of pile, thickness and modulus of the cushion change. Then it analysis different working condition of mattress layer of rigid pile composite foundation making influence in pile soil’s stress ratio, in order to achieve optimization of mattress layer of rigid pile composite foundation design.The research of this paper has practical value, it provides reference for similar engineering construction and researches.