【作者】 朱世哲；

【导师】 徐日庆；

【作者基本信息】 浙江大学 ， 岩土工程， 2004， 硕士

【摘要】 复合地基目前在我国得到了广泛应用，特别是近期刚性桩复合地基在地基处理中应用较多，但对其的研究还较少，本文就依托一个用复合地基处理路基的工程，研究路基中的刚性桩复合地基的性状。 首先，进行了现场试验研究，对比了柔性桩(搅拌桩)和刚性桩(素混凝土桩)复合地基的力学性状。发现正常荷载下，两种复合地基路基的受力性状不一样，用建筑垃圾填土桩距较大的素混凝土桩复合地基，浅层应力向桩体集中，并通过桩向深层扩散，桩间土与桩有较大的相对位移，桩顶和桩端的刺入较为明显。而对于用粉质粘土填土桩距较小的柔性搅拌桩，桩间土和桩的相对位移很小，桩群和桩间土形成了一个加固整体，应力在桩顶和桩端较集中，大部分的荷载传到桩端土和下卧层中，起到了很好的扩散荷载的作用。 接着，结合了现场试验进行建模，对本次现场试验的建筑垃圾杂填土压缩模量进行了参数反演分析，得出了其压缩模量值，并用反演得出的参数进行有限元模拟，可得出刚性桩复合地基处理路基中地基土的附加应力分布，复合地基压缩沉降变化，桩体受力，超孔隙水压随时间变化等，和实测情况进行分析比较。 最后，推导出了带垫层的刚性桩复合地基桩土应力比的计算公式，这个公式将垫层分为弹性体和理想弹塑性体两种情况分别进行推导，考虑刚性桩刺入垫层和下卧层的情况，并对公式进行了分析，得出了在刚性桩复合地基中桩土应力比随着垫层模量和桩模量的增大而增大，但都有一极限值，随桩间土模量的增大而减小，也有一极限值。并推导了刚性桩桩顶刺入垫层深度的计算公式。 本文的创新之处在于比较了不同填土材料的柔性桩(搅拌桩)和刚性桩(素混凝土桩)复合地基处理路基的性状。对现场试验的建筑垃圾杂填土压缩模量进行了参数反演分析。导出了带垫层的刚性桩复合地基桩土应力比的计算公式和刚性桩桩顶刺入垫层深度的计算公式，并对影响公式的多个参数进行了分析。更多还原

【Abstract】 The Mechanics Property of Rigid Pile Composite Foundation in RoadbedIn these days, composite foundations have been extensively used. Especially the rigid pile composite foundation is paid attention to in Practice engineering. But less research work has been done, this paper works on it.The first, site experiment is carried out. the paper analyze in-situ testing data of subgrade which is made up of plain concrete pile composite foundation and agitation pile composite foundation including pore pressure, layer settlement of soils between piles, earth pressure, lateral deformations. It is found mat many factors under working load are different between agitation pile composite foundation and plain concrete pile composite foundation, and analyze the reasons, describe the factors of two composite foundations under working load.The second, the module of the ground consisted of construction garbage is inverse analyzed with finite element analysis. Then some mechanics rule of rigid pile(plain concrete pile) composite foundation is educed. The rule of settlement and pore stress is educed too. Then it is compared with the case which is found in site.Finally, the paper studies the computing method of pile to soil stress ratio of rigid pile composite foundation with cuhion, and these conditions are thought that the top of pile pierce into cushion and the bottom of pile pierce into underlayer.lt is assumed that the cushion is ideal elastic mass and ideal elastic-plastic mass, then the formula is developed and all parameters ’effects to stress ratio of pile to soil are discussed.更多还原