【作者】 谢志勇；

【导师】 苏永华；

【作者基本信息】 湖南大学 ， 岩土工程， 2010， 硕士

【摘要】 边坡的稳定性是岩土工程所关注的重要问题之一。目前边坡稳定性分析方法很多,归结起来可分为两类,即确定性方法和不确定性方法。确定性方法如极限平衡法,作为边坡稳定性分析评价的传统方法,通过安全系数来定量评价边坡的稳定性,由于安全系数的直观性,因而被工程界广泛应用。但边坡工程设计和分析中涉及大量不确定性因素,而极限平衡法作为确定性分析方法,忽略了不确定性的影响,因而安全系数难以真实反映评价边坡的稳定性。可靠度分析方法作为不确定性方法,以可靠度指标或失效概率来评价边坡稳定性,在边坡的稳定性分析中能考虑边坡材料的不确定性因素,较极限平衡法更具合理性,但工程应用不方便。针对上述问题,将逆可靠度分析方法引入边坡的稳定分析评价中,在一定可靠度水平下,求得边坡稳定安全系数,融合安全系数的简单明了与可靠度指标的合理性,综合评价边坡的稳定性,这也符合运用多种方法综合评价边坡稳定性的发展趋势。本文阐述边坡稳定分析极限平衡法和可靠度分析法,并在可靠度分析理论的基础深入探讨了逆可靠度问题及逆可靠度各种分析方法,对基于验算点法的一次逆可靠度分析方法进行了详细介绍。然后在上述理论基础上,建立了基于瑞典条分法和Bishop法圆弧滑动面边坡稳定逆可靠度分析求解格式,并对算例进行了分析探讨,验证了逆可靠度法用于边坡稳定性分析的有效性和可行性。在此基础,将逆可靠度分析方法推广到任意滑动面边坡稳定性评价分析中,建立Janbu、Spencer和郎畏勒模式下逆可靠度分析的求解格式及计算步骤。在上述分析的基础上,利用Visual Basic6.0编制了Windows环境下运行的可视化的边坡稳定逆可靠度分析程序。该程序操作简便,适用于多岩土层非均质任意形状滑裂面边坡稳定分析,具有边坡稳定确定性分析和逆可靠度分析两大功能,便于计算结果的比较分析。然后运用逆可靠度分析程序对多个算例和工程实例进行分析讨论,并将分析结果与确定性分析结果进行对比,表明在边坡的稳定性分析中,忽略岩土参数的变异将会导致过高估计边坡的稳定性,使边坡偏于不安全。将逆可靠度法用于边坡的稳定性评价既满足了给定的可靠度水平,又考虑岩土参数的不确定性,更能反映边坡的真实情况,同时又以安全系数来评价边坡的稳定性,便于工程应用。更多还原

【Abstract】 The stability analysis of slope is one of the most important questions in geotechnical engineering. Many methods of slope stability analysis can be summarized into two categories:deterministic methods and probabilistic methods. Deterministic methods, such as Limit equilibrium method which is traditional method in slope stability analysis uses factor of safety to evaluate stability of slopes, are the basic method of slope stability analysis. Because of factor of safety brief and easy to understand, it is widely used in engineering. But many sources of uncertainty are involved in the analysis; Factor of safety hardly reflects stability of slope truly. The reliability method as a method of probabilistic methods evaluates slope stability by reliability index or probability of failure. The reliability method considers the uncertainties of soil properties in slope stability analysis, so compared with limit equilibrium method is more reasonable, but its application is limited because of imperfect in theory. Address these issues, the inverse reliability method is proposed in slope stability analysis, calculate factor of safety at a given reliability index. Thus, the proposed method learns the advantages of both above method:briefness of Limit equilibrium method and reasonable of reliability method, to composite evaluate slope stability. This is also consistent with trends that the use of various methods to estimate slope stability.In this paper, it introduces the basic theories of stability analysis and reliability analysis,firstly. On the basis of these, take deeply study of the inverse reliability method, and take much time to introduce the inverse first order reliability method (FORM). Based on the above mentioned theory, schemes of inverse reliability analysis at Terzaghi Model and Bishop Model are established, which are in connection with circular slip surface. Some examples have been used to test and verify feasibility of the inverse reliability in slope stability analysis. Then, the method is extended to stability analysis of non-circular slip surface slope. Based on Janbu and Spencer Models, the format and calculation steps are establish for inverse reliability analysis.Based on the above analysis, a program using Visual Basic 6.0 language has been developed and it can run in Windows environment. The program can use the inverse reliability method and Limit equilibrium method to evaluate stability of slope with multilayer and arbitrary slip surface. It facilitates comparison of results.Then, several examples are discussed by the program of the inverse reliability analysis, and the results will be compared with the deterministic analysis, which show that slope stability analysis, ignoring the variability of geotechnical parameters, will lead to overestimation of the slope stability, so that slope is unsafe. The inverse reliability method developed to slope stability evaluation not only meet a given reliability level, but also take into account the uncertainty of geotechnical parameters, to better reflect the real situation of slope. At the same time, it is convenient to application and evaluates the slope stability by safety factor in engineering project.更多还原