Characteristics And Numerical Simulation Of Jacked Pile Driving In Saturated Clay

With the increasing number of projects in China's engineering construction,the construction level of modern foundations is also getting higher and higher.Due to its high bearing capacity,good stability,small settlement and uniformity,low sedimentation rate and fast convergence,the pile foundation has been widely used in engineering practice.At present,static pressure piles have won the favor of construction projects along the coastal soft soil areas along the Yangtze River due to their low noise,low pollution,high construction efficiency and small damage to the pile body.The static pressure pile belongs to the soil replacement pile,which will adversely affect the pile circumference and the pile end soil during the pile sinking process.Therefore,the study of the characteristics of piles can help us effectively estimate the impact of soil compaction on public facilities such as surrounding buildings,and reasonably estimate the bearing capacity of piles.The main work of this paper is as follows:(1)Based on the expanded Lade-Duncan failure criterion,the cylindrical cavity expansion theory is applied to study the squeezing effect of jacked pile in saturated soil;The open pipe pile belongs to the semi-squeezed soil pile,the theoretical solution of the cylindrical cavity is derived under the premise of considering the plugging effect,and the rationality of the solution was verified by model test.(2)The theory of spherical cavity expansion is analyzed for the squeezing effect of pile end during static pressure pile sinking in saturated soil.Based on this,the theoretical formula of ultimate pile end resistance is obtained.The model test records the pile end resistance in the whole process of pile sinking,and compares it with the theoretical value of the ultimate pile end resistance.It is considered that the solution is more suitable for the estimation of bearing capacity of long piles.(3)In order to observe the soil squeezing effect of jacked pile more intuitively,the large-scale general finite element analysis software ABAQUS is used to simulate the continuous penetration process of static pressure piles,the law of pile-soil interaction is studied,and the soil stress field and displacement field during pile sinking process were obtained,and the pile end resistance of pile sinking is analyzed.