Finite Element Analysis Of Cast-In-Situ Piles With Expanded Branches And Plates Under Lateral Load

Cast-in-situ piles with expanded branches and plates based on common concrete bored piles are new type of piles foundation, which have the specialty of high bearing capacity and have been marked both economic and social benefits. People have paid attention to their bearing capacities of vertical load in the early analysis. In recent years, due to the development of engineering, such as ocean, road and bridge engineering, people begin to notice the bearing capacity of the pile under lateral load. The bearing capacity of vertical load of the pile is recommended. However, the bearing capacity of the cast-in-situ piles with expanded branches and plates under lateral load still need some further researches. This paper makes the numerical simulation of the bearing capacity of the cast-in-situ piles with expanded branches and plates under lateral load by the ANSYS software. The bearing mechanism and failure pattern of the cast-in-situ piles with expanded branches and plates under lateral load are analyzed systematically.The main original work includes:Firstly, With the ANSYS software, design the three-dimension models of the cast-in-situ piles with expanded branches and plates and the general pile, the rational program has been modified to analyze pile of this kind. In the calculation, the D-P model is chosen to consider the gap distance and sliding distance of soil-pile interface that adopts the surface-surface contacting element.Secondly, based on the results of finite element analysis by the ANSYS software, It is demonstrated that the bearing ability of the cast-in-situ piles with expanded branches and plates is enhanced greatly because of setting the branches and plates.The final conclusions can be summarized that the bearing ability of the cast-in-situ piles with expanded branches and plates will be increased while the branches and plates are more close to the ground. Furthermore, for a lateral and vertical double-load case, the lateral bearing ability of the cast-in-situ piles with expanded branches and plates will also be enhanced. But the increment is a limited one.Thirdly, by the designed model of pile-soil-pile caps interaction, we studied nonlinear work character of cast-in-situ group piles and general group piles under lateral load. The stress and displacement curve were acquired in nonlinear working condition. Based on these results, we analyzed the pile-soil bearing mechanism and their nonlinear interaction law with change of load in different intervals. The result show that the influence of pile intervals is remarkable.It lay down a basis for further developing the theory for composite foundation.At last, by comparison analysis of the distributions of stress and displacement of the cast-in-situ piles with expanded branches and plates and the general pile with contacting element and without contacting element, it was found that the models with contacting element is better.