【作者】 吴明玉；

【导师】 谢永利；

【作者基本信息】 长安大学 ， 岩土工程， 2008， 硕士

【摘要】 在软土地基处理方法中,刚性桩复合地基由于桩体自重及刚度过大的缘故容易发生刺入破坏,甚至在施工成桩期间就深陷于软基中不能起到处理地基的作用;散体类的柔性桩复合地基往往由于桩间土不能提供足够大围压而发生鼓胀破坏;排水处理方法需要足够宽裕的工期;换填法一般只是针对浅层软土等等。论文根据极软的软土地基处理的需要,避免现有软基处理方法的不足,提出了应用超轻材料作为复合地基竖向增强体进行软土地基处理的新方法。本文应用MARC有限元分析软件试算出在拟定工况下的超轻材料桩体的基本参数。根据数值计算得到的桩体材料参数,在工程实际中优选可行材料,首选聚苯乙烯泡沫塑料(EPS)。EPS在处理软基中利用其独特的物理力学性质减小土中附加应力以及提供一定的上浮力来达到处理效果并且能够很好地避免普通处理方法的不足。通过有限元对比分析发现在极软的路基中,当普通材料桩复合地基和超轻材料桩复合地基达到同等的处理效果时,前者的桩长要远长于后者的桩长;通过离心模型试验,对EPS桩复合地基的受力变形以及破坏形态做了较为系统的研究,并且和未处理软基的沉降变形进行对比分析,EPS桩复合地基以其平缓的地表沉降和良好的工作状态显示了良好的软土地基处理效果。分析成果表明采用超轻材料桩复合地基处理软基是可行的。更多还原

【Abstract】 In the treatments of soft soil foundation, rigid pile composite foundation with the too large deadwight and rigidity always can not play a role in dealing with the foundation because of the punching failure or even falling into the soft foundation during the construction; non-uniform type flexible pile composite foundation often occurs the swelling failure because of the soil between piles can not provide enough pressure; drainage treatments need adequate construction period; replacement methods generally only aim at shallow soft soil, and so on. According to the demond of soft soil foundation treatments and avoiding the lack of existing soft soil foundation treatments, this paper puts forward the new method that using super light material as the vertical reinforcement of composite foundation to dealing with soft soil foundation.Using the finite element analysis software (MARC) to calculate the basic parameters of super light material pile composite foundation in the assumed condition. According the material parameters to select the feasible materials,and the preferred material is foamed polystyrene (EPS). EPS using its unique physical to decrease the additional stress of soil and provide buoyancy to avoid the deficiencies of common materials pile composite foundation in dealing with the soft soil foundation. By finite element comparative analysis found that, when the composite foundation of common materials and super light material to achieve the same treatment effect in soft roadbed, the former need to set up a longer length, the latter on this point is better than the former;Through the centrifugal model test, form a systematic research on the deformation and failure mode of EPS pile composite foundation, meanwhile the settlement deformations of soft soil foundation without treatment and EPS pile composite foundation were comparative analyzed, EPS pile composite foundation shows its advantages in dealing with soft foundation again for its gently surface settlement and good working conditions. Analysis of the results showed that use of super light material pile composite foundation to deal with the soft soil foundation is feasible.更多还原