Bearing Capacity Analysis And Relevance Research Of Single Pile And Pile Group In Soft Soil Stratum

As one of the main ways of soil reinforcement in deep foundation pit,the application of pile group foundation is increasing in engineering.However,there is a weak link in the study of pile-pile foundation,and there is still a lot of blindness in the analysis of the correlation between single pile and pile group.For example,the study of pile foundation can not only consider the settlement,the pile foundation axial force,pile end resistance and so on are worthy of our thorough discussion.It is unreliable in pile foundation design to use bearing capacity of single pile foundation by experience to estimate pile group foundation bearing capacity,and the inaccuracy of carrying capacity will also cause a lot of problems in the normal use of the pile group foundation.In the use of Midas/GTS numerical simulation software to simulate the process,it is proposed that the modified Mohr-Coulomb constitutive model can simulate the soft soil strata better.To avoid the deviation of the pile foundation simulation,improve the accuracy of numerical simulation results.Takes Midas/GTS as the main test method,the “ Technical Code for Building Pile Foundations”JGJ94-2008 as the experimental basis.Simulated testof single pile foundation is conducted,discussed the bearing capacity of single pile foundation under load.The axial force of pile body decreases with the depth of pile depth,and the percentage of load on pile side is larger than that of pile end.It is proved that the experimental model is accurate and reliable through the empirical parameter method of vertical ultimate bearing capacity of the technical code.The numerical simulation method was used to analyze the model of 9 grid piles with pile spacing of 2.5d and pile length of 15 m in soft soil foundation.Discussed the difference of center pile,side pile and corner pile of group foundation pile.It is showed that the maximum settlement in the same pile cap is center pile,then the side piles,angle pile is minimum.For the analysis of the axial force of pile,it is showed that the angle pile is larger than that of the side pile,and the side pile is larger than that of the central pile.As for the percentage of the load on the side of the pile side friction,the center pile bear the most,then the side pile,the smallest pile,angle pile is minimum.The situation of pile end resistance is opposite.The numerical simulation test is taken on the spacing of pile foundation under 9 grid pile groups.The settlement of pile group,pile axial force and pile end resistance are discussed.It is concluded that the bearing capacity of pile group is optimal when the pile spacing is 3 times that of the diameter of the pile.According to the different length of pile foundation,the bearing capacity of pile group foundation is analyzed and compared,and the bearing capacity of pilegroup foundation is increased with the increase of pile length from the settlement of pile foundation,pile axial force and pile end resistance.But the pile length is too long will not have a greater impact on the pile group foundation.Selected the main factors affecting the bearing capacity of pile foundation and pile length and pile spacing,the bearing capacity of single pile foundation and pile foundation are studied.Putting forward on the basis of the single pile foundation and pile foundation formula of relationship between the bearing capacity,which provides a scientific basis for estimating the bearing capacity of pile foundation in practical engineering.