Application Study Of Advanced Reinforced Pipe Piles In The Yellow River Sedimentary Area

The advanced reinforcement pipe pile is a new pile foundation which is compounded by cement soil and prefabricated pipe pile.The pile foundation has the characteristics of fast construction speed,high carrying capacity,low environmental pollution and low comprehensive cost.This kind of pile foundation has been applied in Zhengzhou area,but the research on the bearing characteristics of the Yellow River sedimentary area is still not perfect.In this paper,the prefabricated pipe piles are taken as the research object,and the bearing characteristics of the new pile foundation are studied by theoretical analysis,finite element test and in-situ test based on the stratum characteristics of the Yellow River sedimentary area.The main results are as follows:1.Combine with the construction experience of the actual project,research and summarize the construction process,process and equipment parameters of the advanced reinforcement pipe pile,analyze and summarize the key control points in the construction process,and summarize the problems and solutions that are easy to occur during the construction process..2.Based on the mechanical properties of the pile material,the pile load distribution law and force characteristics of the prestressed pipe pile under vertical load are theoretically analyzed,and the load of the pre-reinforced pipe pile is established based on the load transfer method.Pass the model.It is found that under the vertical load,the pipe pile is the main force-bearing member,the pipe pile and the cement soil satisfy the deformation coordination condition,and the composite pile mainly has three failure modes,namely the “piercing damage” of the pipe pile,the pipe pile and The "integral penetration damage" of the cement soil and the destruction of the pile body material.The research shows that the simplified calculation and analysis method of single pile settlement in this paper can well describe the change process of pile foundation under vertical load.3.Based on the characteristics of the soil layer in the Yellow River sedimentary area,the ABAQUS finite element software was used to simulate the mechanical behavior of the prestressed pipe pile under vertical load.The effects of reinforcement zone diameter,pipe pile diameter,cement mixing ratio and pile end expansion head on the bearing characteristics of the prestressed pipe pile are summarized.The bearing mechanism of the single pile under vertical load is analyzed.4.The in-situ test of a pre-reinforced pile in Zhengzhou area is studied and analyzed.The load-displacement curve of the test pile is analyzed and studied.It is found that the pre-reinforced pile is the working property of the friction pile.The calculation formula of single pile bearing capacity of similar pile type is compared and analyzed.Based on theoretical analysis,finite element test and in-situ test,the calculation formula of vertical bearing capacity of single pile is proposed.