Numerical Simulation Of Horizontal Bearing Capacity Of PHC Pipe Piles With Different Joint Structures

In recent years,my country’s construction industry has developed rapidly,and the strength of the foundation determines the entire building,which must be paid attention to.As a kind of pile foundation,prestressed concrete pipe piles not only have high bearing capacity and short construction period,but also have high unit bearing capacity and have been widely used.When PHC pipe piles are used as pile foundations,the role of horizontal bearing capacity cannot be ignored.Earlier designers focused on the vertical bearing capacity of the pile foundation and seldom considered the influence of horizontal load.Only arranging inclined piles in the foundation to assist the vertical piles caused unnecessary waste and easily brought safety hazards.As there are more and more high-rise buildings in the city,the requirements for wind load and earthquake fortification are getting higher and higher,so the horizontal force that the pile foundation bears is also increasing,especially the connection node between the PHC pipe pile and the cap is the weakest In places where it is urgently needed,people need to improve it.In this paper,on the basis of PHC pipe piles and double piles,considering the effect of soil,the ABAQUS software is used to numerically simulate and analyze the three types of pile-cap joints: ordinary filling type,reinforced ring type and rigid type.The performance of each under the horizontal bearing capacity,and the parameter analysis,the results obtained can provide reference for future joint design,the main content and conclusions of this paper are as follows:(1)Ordinary core-filled nodes can increase the horizontal bearing capacity at the nodes,but their ultimate bearing capacity is relatively poor compared to the other two types of nodes.As the depth of the pile embedded in the platform increases,the bearing capacity of the joints also increases.It is recommended that the embedded depth is 300 mm for the best effect;as the length of the pile increases,the bearing capacity of the pile body also increases,but the effect is not obvious;With the increase of the pile spacing,the influence of the pile group effect becomes smaller and smaller.When the pile spacing is 6 times the pile diameter,the pile group effect may not be considered.(2)Reinforced ring-shaped joints Due to the presence of reinforced ring concrete at the joints,the concrete at the pile head is protected from premature damage and its bearing performance is improved.The size of the reinforcing ring determines the improvement effect.It is recommended that the wall thickness of the reinforcing ring is 200 mm and the length is800 mm for the best effect.(3)Stiff nodes have the best effect on improving the bearing performance of the nodes,because the presence of T-shaped steel parts at the nodes makes the nodes have high bearing performance.The stress analysis of the T-shaped steel parts shows that the stress level of the transverse limbs is smaller than that of the vertical limbs;and the number of transverse limbs is analyzed with parameters.According to the difficulty and economy of construction,it is recommended to choose T-shaped steel with one cross-leg.