Research On The Sinking-pile Mechanism And The Sinking-pile Effect Of The Taper-cylinder With Holes Combined Pipe-pile

With the continuous development of China’s urbanization process,urban land is becoming more and more tense.How to reduce the impact on the surrounding environment during the construction of the project has become a major subject worth studying.As we all know,static pressure pipe-piles are widely used in many construction projects,but the squeezing effect of pipe-piles during the pile sinking process will adversely affect the surrounding environment.Therefore,in order to mitigate the adverse effects of the construction of pipe piles,a cone-hole cylindrical combined pipe-pile technology is proposed.Its advantages are mainly reflected in:First,the opening can allow soil water to enter the pipe cavity freely,thereby reducing the excess pore water pressure and accelerate its dissipation;the second is to use the wedge-shaped side of the pile to give full play to the interaction between the pile and the soil,complementing each other.In this paper,the conical-perforated cylindrical composite pipe-pile is selected as the research object to explore the static pressure sinking effect mechanism of the conical-perforated cylindrical composite pipe-pile.In this paper,the theoretical analysis combined with numerical simulation is used to study and discuss the soil squeezing effect of the conical-perforated cylindrical composite pipe-pile.Based on the theory of circular hole expansion,the pile sinking mechanism and sinking-pile effect of the cone-hole cylindrical composite pipe pile during the sinking-pile process are studied,and the excess pore pressure of the cone-hole cylindrical composite pipe-pile during the sinking process is derived Analytical formulas for the relationship between radial distance,pile sinking rate,depth and aperture diameter.Using numerical simulation to simulate the penetration process of the pile,the relationship between the excess pore water pressure of the conical-perforated cylindrical composite pipe-pile and various factors is obtained,which verifies the correctness of the theoretical analysis.Specific research results are as follows:(1)Derive the analytical formula between the super-pore water pressure of the soil around the cone-hole column combination pipe-pile and the radial distance,sinking-pile rate,depth and opening hole diameter,and draw it through theoretical derivation The curve between the relationship between the excess pore pressure of the conical-perforated cylindrical composite pipe-pile and various influencing factors,and its variation law conforms to the general characteristics of excess pore water pressure;the super-pore water pressure plastic zone of the conical-perforated cylindrical composite pipe-pile The internal maximum is much larger than the elastic zone.(2)Using the ABAQUS finite element analysis software,the numerical simulation of the dissipation of excess pore water pressure during the sinking process of the cone-hole column composite pipe-pile is carried out,and the excess pore water pressure of the cone-hole column composite pipe-pile is obtained.The radial distance increases gradually and gradually decreases with the increase of the opening diameter;when the radial distance is the same,the excess pore water pressure of the conical-perforated cylindrical composite pipe-pile increases continuously as the pile sinking depth increases.The pile sinking rate increases gradually.(3)Comparing the numerical simulation analysis and calculation results of the super-pore water pressure of the conical-perforated cylindrical composite pipe-pile with the theoretical research results,it is found that the trend of the two curves is basically the same.