The Analysis Of PHP Pipe Pile’s Compacting Effects In Old Clay Area Of Anhui

The construction of prestressed concrete pipe pile(PHC)can causes significant compacting effects.The soil around the PHC will move far from the PHC.This may led to quality problem about PHC.With the popularization and application of prestressed concrete pipe pile in China.More and more study of soil compacting effect are researched by experts and scholars.The main research methods consisted of cavity expansion method,strain path method and finite element method.A large amount of engineering data of Anhui are collected,and the indoor experiments and outdoor tests have been done to study on characteristics of old clay in this paper.The analytic solutions on displacement fields and stress fields are evaluated basis on cavity expansion method.The analytic solutions are applied to engineering practice to solve engineering problems.the abaqus is adopted for numerical simulation in Simulating piling process.Radial,vertical and circumferential displacement fields and stress fields are researched through results of numerical models.Some characteristics of old clay have been found in this paper.it includes swelling and dilatancy.The dilatancy develops mainly when the axial strain is less than 5 percent in the triaxial tests.after that,the dilatancy will not develop and remain around 1 to 3percent.It is found that the average of plastic zone radius of the pile is 2.8 times of the pile diameter according to analytic solutions basis on cavity expansion method,but the result is from 4 to 7 times of the pile diameter according to abaqus numerical numerical simulation.And the the consolidation time of soil is 18 days basis on the result of Abaqus numerical simulation.The excess pore water will dissipate completely and the displacement and stress will become stable after 18 days.Some measures are researched for reducing or eliminating the compacting effects.It includes increasing pile spacing,pre drilling,reasonable arrangement the piling order,reducing piling speed,setting the anti compacting effects ditch and wall.