【作者】 刘恒新；

【导师】 龚晓南；

【作者基本信息】 浙江大学 ， 岩土工程， 2004， 硕士

【摘要】 在软土地基修建高等级公路中，解决“桥头跳车”问题是一个技术难题。低强度桩复合地基是一种新型的处理桥头深厚软基的工法。目前低强度桩复合地基在高等级公路软基处理中的应用还不多，其在堆载作用下的性状研究的比较少。本文借助于低强度桩复合地基处理桥头深厚软基的实际工程，对低强度桩复合地基加固桥头软基进行了试验研究，做了以下工作： (1)对低强度桩复合地基加固高等级公路软基的方法进行了总结； (2)对低强度桩复合地基加固软基的试验方法进行了总结； (3)研究了低强度桩复合地基在堆载作用下的变形性状； (4)研究了低强度桩复合地基在堆载作用下的应力场特征，并对不同性质荷载作用下低强度桩复合地基桩土应力比进行了比较，分析了存在差异的原因原因； (5)对低强度桩复合地基承载力的计算方法进行了探讨。 研究结果表明，采用低强度桩复合地基加固桥头软基时，可以采用变桩长、变间距的设计思想，使沉降逐渐过渡，减轻桥头跳车的危害，并且还可以减小沉降和深层土体水平位移，减小对桥台及其桩基的水平推力，提高地基承载力。基于以上研究结果，可以预计低强度桩复合地基在高等级公路软土地基处理中具有广阔的应用前景。更多还原

【Abstract】 In the express way construction on a soft foundation, resolving "bump at bridge-head" is a difficult technical problem. Low intensity piles composite foundation is a new method which can improve the soft foundation at bridge approaches. Now the application of low intensity piles composite foundation in soft foundation of express way is scarce and the character of low intensity piles composite foundation under embankment loading is misty. Via the practical engineering of improving the soft foundation with the low intensity piles composite foundation the field test study is done. These work is done:(1) The method of improving the soft foundation of the bridge approach with the low intensity piles composite foundation is summarized;(2) The field test method of improving the soft foundation of the bridge approach with the low intensity piles composite foundation is summarized;(3) The strain character of the low intensity piles composite foundation under the embankment load is studied;(4) The stress character of the low intensity piles composite foundation under the embankment load is studied and the differences of the pile-soil stress ration and what make them is discussed;(5) The calculating mode of bearing capacity of low intensity piles composite foundation is discussed.The results indicate that this method can minish settlement largely, decrease level thrusts on bridge abutment, make the settlements transition, improve the bearing capacity of foundation soil and its economic benefits are notable. The results of field test show that low intensity piles can put into widely use in soft foundation of express way.更多还原