高速公路软基路堤失稳风险分析方法研究

【作者】 罗成才；

【导师】 李军；

【作者基本信息】 中南大学 ， 道路与铁道工程， 2011， 硕士

【摘要】 随着经济的飞速发展,修筑在软土地基上的高速公路越来越多,软基路堤稳定性分析评价也益发凸显出其重要地位。影响高速公路软基路堤稳定的因素众多,且各因素之间相互联系、密不可分。目前工程界常用的软基路堤稳定性评价方法主要是基于传统极限平衡原理的一些改进方法,如瑞典条分法、简化Bishop法、Janbu法、Morgenstern-Price法等,这些方法简单易懂,且经过了大量工程实践的检验。但是,由于传统极限平衡法对求解做了许多简化假设,在某些情况下得到的结果与实际可能会产生较大的偏差。针对软基路堤影响因素多而杂的特点,引入风险分析与评价理论,综合考虑软基路堤稳定的各种主要影响因素,结合工程实际,构建一套适宜的软基路堤稳定风险评价模型,具有重要的理论研究意义及工程实用价值。论文首先对国内外工程风险分析及软基路堤稳定性分析研究现状进行了归纳分析,对该课题目前的热点及难点问题进行了阐述,在此基础上提出了论文的主要研究内容及框架结构。论文的主要研究内容包括以下几个部分：(1)论文在阐述了软基地基的性质及软基处理常用方法的基础上,对软基路堤的失稳破坏形式、影响因素进行了分析归纳,对传统的路堤稳定评价方法——极限平衡法及目前运用较为普遍的有限单元法进行了对比介绍；(2)基于软基路堤失稳破坏的特点,论文引入了灾害风险分析理论来评价软基路堤稳定,首先介绍了灾害风险分析的基本概念、风险分析的基本流程以及常用的评价方法,对软基地基路堤失稳破坏的影响因素进行了辨析,依据软基路堤失稳是一个由渐变累积到突变过程的特性,论文引入突变级数法进行分析评价。(3)系统介绍了初等突变理论,建立了基于初等突变理论的软基路堤稳定突变级数评价模型,给出了评价指标,构建了软土地基路堤稳定风险评价矩阵。(4)将软基路堤稳定突变级数风险评价模型运用到沈海高速公路软基路堤的稳定安全评价中,并分别运用基于极限平衡法的岩土理正及有限元软件FLAC SLOPE对突变级数评价结果进行了验证分析。分析表明,运用该方法对软基路堤的稳定进行评价分析是合理可行的。更多还原

【Abstract】 With the development of the economy, there are more and more highway which was builded on the soft ground, how to evaluation it’s Stability become one of Major challenges which we have to confront. The Stability of soft soil embankment is influencd by many factors, and the various factors are interrelated and inseparable. The commonly used evaluation methods of soft soil embankment Stability and safety are based on traditional limit equilibrium principle and some improving methods for the present, such as the Swedish slice method、simplified Bishop method、Janbu method、Morgenstern-Price method etc, these methods are simple and easy to understand, and have been successfully used in many engineering practices. As the traditional limit equilibrium method have been made a lot of simplifying assumption, in some cases, the results obtained were produced a large deviation from the actual. AS there are so many miscellaneous factors influence the Stability and safety of soft soil embankment, considering the variety of factors and engineering practice, this paper introduce Risk Analysis and Evaluation theory to evaluation it’s Stability and safety, to construct a set of appropriate and mature safty risk evaluation index system of soft soil embankment, of great theoretical significance and practical economic value.First of all, the dissertation researches Engineering disaster risk assessment and the Failure mechanism of soft base embankment at home and abroad, then discusses the current hot topics and the difficult issues, based on this, the main research contents and paper frame structure are given. The main research includes the following sections:(1) This paper simply discusses the properties of soft soil foundation and the common methods of soft foundation treatment, then soft soil embankment failure modes and the influencing factors are analyzed and summarized. The traditional embankment stability evaluation method of limit equilibrium method and currently using relatively general finite element method are given a contrast introduction.(2) Based on the characteristics of soft soil embankment instability and failure, this paper introduce Risk Analysis and Evaluation theory to evaluation it’s Stability and safety, at first, briefly introduced the basic concepts of disaster risk、the process of risk management and the commonly used evaluation methods, then analysis the influence factors of instability and failure of soft soil embankment, as the instability of soft soil embankment is a gradual process of accumulated mutations, this thesis introduced Catastrophe progression method to to evaluation it’s Stability and safety.(3)Give a detailed description of the elementary catastrophe theory, then basing on elementary catastrophe theory, the soft soil embankment safety risk evaluation model is established, set up the safty risk evaluation indexs, construction of a safty risk assessment matrix of soft soil Embankment.(4) Using the safty risk assessment matrix of soft soil Embankment to evaluate the stability safety of Shenhai Expressway, and compared the results with the results calculated by Soil management software and Flac slope, which base on limit equilibrium principle and finite element method.The results show that the method of soft soil embankment safety risk evaluation is Reasonable and feasible.更多还原