【作者】 温世清；

【导师】 刘汉龙；

【作者基本信息】 河海大学 ， 防灾减灾工程及防护工程， 2004， 硕士

【摘要】 现浇混凝土薄壁管桩(简称PCC桩)及其复合地基是一种全新的地基处理新技术，已应用于高速公路、民用建筑、港口、海堤等工程建设中，PCC桩在处理效果、工期、造价、环保等方面具有较大的优越性，因此在地基处理中具有广阔的应用前景。本文在借鉴其他桩型的研究的基础上，通过现场试验研究和理论推导，对PCC桩处理软基加固机理、沉降计算和优化设计等进行了较为深入的研究和探讨，具体包含以下几方面的内容： (1) 在与预制管桩和沉管灌注桩等桩型比较的基础上，对PCC桩的优缺点、施工机具设备、施工工艺、技术作用机理以及PCC桩复合地基技术特点等进行了述评。 (2) 进行了PCC桩及其复合地基现场试验研究，对PCC桩及其复合地基加固机理进行简要分析。 (3) 基于PCC桩—土—垫层所组成的一个工作体系，综合考虑各部分的工作特性及相互影响，对PCC桩进行整体分析，建立桩体平衡方程，考虑PCC桩在褥垫层及下卧层中的上、下刺入量对复合模量的影响，并通过迭代的方法最后确定桩体模量发挥系数，提出了一种求解PCC桩复合地基模量的计算方法，进而得到PCC桩复合地基的沉降计算和桩土应力比公式。并运用工程实例进行了验证，与实际情况符合较好。 (4) 根据本文建立的沉降计算方法，对复合地基模量的主要影响因素：置换率、褥垫层弹模、桩体模量、基床系数等进行探讨，最后得出了它们和复合地基模量之间的关系曲线。 (5) 建立了PCC桩复合地基优化设计的目标控制函数和两个约束条件：沉降控制条件和承载力校核条件。并根据对PCC桩复合地基影响因素的讨论，对PCC桩复合地基设计参数的设计进行了讨论，提出了相应的优化设计方法和具体实施步骤。更多还原

【Abstract】 As a new foundation improvement technology, The cast-in-situ concrete thin-wall pipe pile (PCC pile) is applied widely in the construction of the highway, civil architecture, haven and sea embankment etc. The PCC pile has a great prospect because it has superiority in the treatment of soils, such as construction period, cost and environment protection. Based on the study idea of the former pile else, this paper has conducted and discussed the mechanism of consolidation, settlement calculation and optimization design of the PCC pile according to the test in situ results and reasoning. It includes the followings in detail:(1) Compared with the precast tube concrete pile and tube sinking concrete pile, the merits and shortages, construction machine, construction technology of the PCC pile and PCC pile composite foundation are introduced in detail to make the PCC pile be known completely by engineers.(2) The test of the PCC pile and its composite foundation in situation is carried out and the consolidation mechanism was discussed according to result of the test in situation.(3) Based on the working performance and mutual influence of the system of PCC pile-soil-cushion, PCC pile composite foundation is discussed in elastic method. A new calculation method of composite modulus of the PCC pile composite foundation is developed. Furthermore, Pile-soil stress ratio and settlement can be derived from the proposed method in this paper. Finally, it is proved the method is practicable and applicable in the field by a practical engineering.(4) According to the settlement calculation method in this paper, the main influence factors, such as displacement ratio, modulus of cushion, modulus of pile, and coefficient of subgrade, are discussed in this paper and the curves that reflect the relationships of the composite modulus and the influence factors have been achieved.(5) The governing object function and two boundary condition: settlement and foundation bearing capacity are developed in the optimization design of the PCC pile composite foundation. The design parameters of the PCC pile composite foundation are discussed and then the optimization design method and process is developed.更多还原