Study On Settlement Computation Method Of The Pile-Net Composite Foundation

The pile-net composite foundation were composed of filled material reinforced cushion,soils in-between piles,reinforced areas and soils underlying piles, the mechanism of its work were very complicated.In this paper, the shape of four-part were analyzed respectively at first. Then their mechanical model and the basic differential equations were established. Next the various parts were composed into a unified whole to build a group of simultaneous equations through the equilibrium equations and boundary conditions. Also the calculation methods for the load sharing ratio,tension force of the reinforcement,pile-soil settlement,elevation of equal settlement plane,axial force and skin friction of the piles were obtained.The law of the settlement and the load sharing ratio which go with the load and time were obtained through the field test in the Beijing-Shanghai high-speed railway.Numerical analyses were also carried out for the typical tested sections using the plaxis software. Calculated results were obtained for the settlements, load sharing, the stresses and strains of the horizontal reinforcement, and the axial forces and skin frictions of the piles. At last the results from the analyzing model, the field tests and the numerical analyses were compared. It verifies that the analyzing model built in this text is capable of reflecting the real working behavior of the pile-net composite foundation. The calculated results are reliable and applicable to the engineering practice.