Settlement Analysis Of Group Piles Under Compressive Or Pull-out Loads With Different Soil Modulus In Tension And Compression States

Group piles under compressive or pull-out loads as a sort of foundation has a wide range of applications for a variety of projects, and the settlement prediction has always been the key research topic in engineering. The most existing methods of settlement prediction of pile foundation is based on the elasticity theory, assuming that modulus of soil in tension and compression are the same. But actually the modulus of soil in tension and compression are different. If theory of elasticity is employed to predict the settlement of pile foundation, especially under uplifting loadings, the errors will not be allowable. So we should use different modulus of soils to predict settlement of pile foundation.In order to consider the different modulus of soil in tension and compression , this text introduces Poisson's ratio in tension to modify Geddes'solution and establishes the method of stresses and settlement prediction with different modulus of soil in tension and compression.Based on the condition of above, this text establishes the compile procedure of MATLAB with which this text analyzes vertical stesses and deformation of group piles under compressive or pull-out loads under the condition that modulus of soils in tension and compression are the same and different. This text also analyzes the axial force of piles, axial deformation of piles, soils'vertical stesses and deformation and the influence of length of piles, diameter of piles,distance of piles,number of piles, module of soils and so on from which we get some important result.Then this text analyzes a piles foundation with one of finite element analysis software ABAQUS and compares results with the compile procedure. The results of two methods are approximated. At last, this text choses a test and analyzes it with the compile procedure. Compareing the results, we can find that using the theory with different modulus in tension and compression to predict the settlement of pile foundation is more accurate. The results prove that the group piles settlement prediction method of this text is feasible and applicable.