【作者】 胡志；

【导师】 胡岱文；

【作者基本信息】 重庆大学 ， 岩土工程， 2004， 硕士

【摘要】 复合地基是目前使用最广泛的地基处理技术之一,随着对地基处理要求的不断提高,复合地基处理技术也在不断的发展当中,素混凝土桩复合地基因其具有的高承载力、小变形和广泛的适应性以及良好的经济和社会效益在近年来得到了迅速的发展。本文回顾了复合地基的应用和发展情况,简要介绍了素混凝土桩复合地基的基本概念,同时在素混凝土桩复合地基的试验研究、有限元分析和理论分析方面做了一些分析和探讨,主要做了以下工作: ①试验研究。 通过素混凝土桩复合地基的现场试验,测得了素混凝土桩复合地基中的桩土应力曲线及荷载与变形的关系曲线,由此得到了素混凝土桩复合地基的桩土应力比和荷载分担比。试验表明,在桩端持力层承载力较好的情况下,桩顶应力、桩间土应力、桩的荷载分担比和桩土应力比都随荷载增大而相应增大;素混凝土桩复合地基的沉降曲线为缓变形曲线且总变形远小于规范规定的上限值。试验表明素混凝土桩复合地基具有良好的承载特性和变形特性。②有限元分析。利用ANSYS6.1有限元分析软件,对天然地基、素混凝土桩复合地基和刚柔组合桩复合地基的承载特性和变形特性进行了对比分析。有限元分析表明,素混凝土桩复合地基和刚柔组合桩复合地基的承载特性和变形特性与天然地基有很大的不同,两者均可有效加固天然地基。③理论分析。 分析了复合地基的各种计算方法之后,提出了采用综合变形模量的概念来计算复合地基变形的计算公式。根据有限元分析的结果,探讨了刚柔组合桩复合地基的承载力和变形计算的实用方法。 介绍了复合地基的破坏模式之后,推导了素混凝土桩复合地基整体稳定性分析的圆弧法公式,分析表明素混凝土桩复合地基有利于提高天然地基的抗滑稳定性;另一方面完善了洞室复合地基稳定性的计算方法。④实例分析。 通过两个典型的工程应用实例对素混凝土桩复合地基的设计、施工和检测方法都作了较为详细的介绍和分析,对类似的工程有一定的参考价值。更多还原

【Abstract】 Nowadays, Composite foundation is one of the most widely used soil improvement technologies. With higher and higher demand to soil improvement, composite foundation technology is developing continuously. Plain concrete pile composite foundation has been developed recently because of its high bearing capacity, little settlement, wide adaptation, good economical and social benefit. This dissertation has summarized the application, development and research of composite foundation and introduced the basic concept. At the same time, there are some analyses and discussions about the test research, finite element analysis and theory analysis.①Test Research.By in-site test to plain concrete pile composite foundation, pile stress curve, soil stress curve and loading-settlement curve were got, then pile-soil stress ratio and load sharing ratio were also got. The test shows, when the bearing capacity of supporting course of piles’ end is good, stress on the top of pile, soil stress between piles and the load sharing ratio will enhance with load’s enhancing. The load-settlement curve deforms slowly and the total settlement is much smaller than the upper limit value which code has regulated. The test shows that Plain Concrete Pile Composite Foundation(PCPCF) has good characters of bearing capacity and settlement.②Finite Element Analysis.Using ANSYS6.1 finite element analysis software, the dissertation has made an comparative analysis to the bearing capacity and settlement of natural foundation, PCPCF and Composite Foundation of Rigid-flexible Composite Piles(CFRCP). The comparative analysis shows that, the two characters of PCPCF and CFRCP are different from those of natural foundation. The finite element analysis also shows both PCPCF and CFRCP can reinforce the natural foundation efficiently.③Theory Analysis.After analysising all kinds of settlement calculation method of PCPCF, the dissertation has come up with using composite deformation modulus to deduce the calculation formula of PCPCF. According to the results of finite element analysis, the dissertation has come up with practical calculating method of bearing capacity and settlement of CFRCP. <WP=7>After introducing failure model of PCPCF, the dissertation has deduced the circular arc method formula of PCPCF’s total stability analysis. The analysis shows that PCPCF can improve the stability of natural foundation. At the same time, the dissertation has also perfected stability calculation method of composite foundation which has caverns.④Examples Analysis.By two typical examples of PCPCF, the design method, construction method and loading test method were introduced and analysised in detail, which can be referenced to similar projects.更多还原