【作者】 叶彬；

【导师】 朱国元； 蒋军；

【作者基本信息】 浙江大学 ， 防灾减灾工程及防护工程， 2005， 硕士

【摘要】 本文阐述了褥垫层的作用机理，通过设置褥垫层，使桩土桩间土之间的应力分别达到调节和平衡，减少了基底的应力集中，并为充分利用桩间土的潜力，节省工程造价提供了有利手段。并提出垫层模量和厚度存在一个最佳值范围。 分析了CFG桩复合地基承载力设计模式，比较了当前常用的承载力估算公式，并对牛志荣等改进的承载力估算公式中单桩承载力标准值R_α的修正系数k，以及桩间土强度提高系数口的取值问题进行了讨论，使该公式更符合工程设计要求。 分析了CFG桩复合地基沉降计算的现状，比较了各种沉降计算方法及其适用性，认为复合模量法的计算假设合理，计算精度高，具有更好的适用性。并推导了复合模量与地基承载力特征值的关系，从而得出CFG桩复合地基沉降计算的经验公式，并对该公式中的复合模量修正系数k_i选取作了说明。更多还原

【Abstract】 The foundation mechanism of the cushion is elaborated in this paper. Through the cushion, the stress ration of pile to soil is coordinated, and the stress concentration can be eased. Hence, the potential capacity of the composite foundation is harnessed and the construction expense is decreased. It’s found that there’re most fitting cushion elastic modulus and cushion thickness.Various calculation methods for ultimate capacity of CFG composite foundation are compared, and methods for computing the correction coefficient in Liu Zhirong method is put forward. Further discussion is made on the change coefficient of the soil strength, which makes the formula more practical in engineering practice.The status and development of settlement analysis methods of CFG composite is summarized and compared in the paper. A fresh formula, which concerns the composite modulus with the ultimate capacity, is deduced. Furthermore, a new settlement analysis method is introduced with engineering justification.更多还原