【作者】 吴平春；

【导师】 李镜培； 吴铭炳；

【作者基本信息】 同济大学 ， 建筑与土木工程， 2006， 硕士

【摘要】 软土地基深基坑支护结构计算中的主要土体物理参数Φ、C取值一直是岩土工程界争论的热门话题，支护结构的计算方法也颇有疑义，有的基坑支护设计过于冒进，导致事故的发生；而有的设计则过于保守，造成经济的巨大浪费。虽然有许多科研、工程技术人员提出了一些建议和改进方案，但付诸实践的并不多见。 本人在借鉴前人研究结果的基础上，根据大量实体工程的监测结果，系统归类、分析软土地层尤其是淤泥土层的土压力变化的情况、基坑支护结构的位移变化、内力发展状况，提出了Φ、C取值方法。通过对支护结构设计计算理论的进一步研究，提出了围护桩稳定性的变化计算法，方便、简单、实用。有限元分析法的研究，使基坑支护结构的计算分析更趋准确、合理。主要研究内容如下： (1)采用反分析法，将现场测得的土压力值利用有关公式反向推算淤泥土层的Φ、C值，总结出Φ、C取值的规律性。 (2)通过对软土地基支护体系的位移特征研究，总结出位移的变化发展过程，以及与Φ、C取值的相关性。 (3)通过对软土地基支护结构的内力特征研究，总结出内力的变化、发展过程，以及与Φ、C取值的相关性。 (4)对支护结构设计计算理论进行研究，通过对比分析，总结出传统的设计计算理论的适用性和局限性，建立一种简易的计算模型，既能保证安全，又能降低工程造价。 (5)通过工程实例，应用得出的Φ、C取值方法，对淤泥土层支护结构计算取值，并利用研究取得的成果将计算结果进行调整，实施于工程中，用监测数据进行验证。更多还原

【Abstract】 The internal friction angle and cohesion of soil are paid more attention to by many geotechnical engineering personnel in excavation support structure calculation of soft ground, but the calculation methods of the support structure are un-properly used usually. For example, a conservative design project could lead to economic waste. However, opened design could cause engineering accident. Although many recommendations and improved schemes have been presented by the researchers and the engineering technical personnel, few of them have been put into practice.Based on a large number of engineering monitoring results, the soft soil layer, especially the soil pressure of the silt stratification, the varying displacement of the excavation support structure, and the development of internal force, has been classified systematically and analyzed to put forward the sampling method about internal friction angle and cohesive force on the predecessors’ research findings. Through the further research about the designed and calculated theory, the calculated method of the stability of the fender post is presented. The method is convenient, simple and practical. The research of finite element analysis makes the excavation support structure analysis more correct and rational. The main research of the paper as follows:Firstly: Using back analysis method, the value of the internal friction angle and cohesive force values were achieved through the soil pressure value acquired on site, and generalized the regularity.Secondly: The displacement developing process and the correlation about the sample of the internal friction angle and cohesive force have been generalized through the research of the displacement character about the support system to soft ground base.Thirdly: For finding out the applicability and insufficiency of the traditional design theory, the design calculation theory was investigated by comparative analysis to found a simple calculation model, which can ensure safety and play down the更多还原