【作者】 李媛；

【导师】 曹文贵；

【作者基本信息】 湖南大学 ， 岩土工程， 2012， 硕士

【摘要】 基桩下伏岩溶顶板稳定性分析与评价是岩溶区建筑物基础设计与施工的关键问题之一。但岩溶顶板作为一种深部地下结构,其不确定参量较复杂且难以获得其足够的数据样本信息。这就使得采用传统概率方法及现有非概率方法刻画其可靠度存在一定的局限性,本文以此为出发点,研究了基于Information-Gap (Info-gap)理论的稳健可靠性方法。首先,基于现有岩溶顶板安全系数在不同失稳模式下的极限平衡分析方法,建立出基桩下伏岩溶顶板功能输出响应模型,由输出响应模型确立了一般评价标准,并通过对满足预定功能的不确定参量的允许不确定性程度变化幅度确定方法的研究,建立出基桩下伏岩溶顶板稳定性的不确定性分析的稳健性分析模型。然后,引入Info-Gap理论,并阐述了该理论的发展过程与主要包含的内容,进而建立出基桩下伏岩溶顶板结构输出响应模型中不确定参量的基于Info-gap模型的不确定性程度度量方法以及评价结构稳健性的稳健函数确定方法,并在此基础上,基于区间组合分析法,建立出基桩下伏岩溶顶板稳定性的稳健可靠度指标确定方法,从而提出基于Info-Gap理论的基桩下伏岩溶顶板稳定性的不确定性分析新方法。该方法对数据信息量要求低,无需掌握不确定参量的分布形态,是对现有相关理论与方法的补充与完善；而且,由于该方法将不确定参量区分为设计变量和设计参数,实现了基桩下伏岩溶顶板稳定性在不同设计变量下不确定设计参数的允许不确定性程度的动态分析,因而,使本文方法既具有被动应对功能,又具有主动处置功能。最后,通过工程实例分析,具体说明了本文方法的操作过程和应用流程,表明了本文方法的合理性与可行性。更多还原

【Abstract】 Stability Analysis and evaluation of karst roof under pile foundation is one of the key issues for the design and construction of foundation of buildings in karst areas. Karst roof, as a deep underground structure, has the characteristic of more complexed uncertain variables. Owing to the inability to obtain a wealth of uncertain information, there are shortcomings of the traditional probabilistic procedure and the present non-probabilistic approach employed to underground structures. From this point, this paper studies the robust reliability method based on the Information-Gap theory which is abbreviated as Info-Gap theory.Firstly, according to the existing limit equilibrium analysis method on safety factor of karst roof under foundation pile under different failure modes, a response output model to the stabilization and security function of karst roof is set up and the general evaluation criteria is established based on the response output model. Also based on the research about the method to determine the allowable change range of these uncertain variables on the condition that the structural performance can satisfy the intended function, robust reliability model is established.Then the Info-gap theory is introduced and the process of the development and the main contents of such theory are elaborated, thereby establishing the measurement method of the degree of uncertainty of uncertain variables as well as the robustness function to evaluate the robustness of structures. Then the calculation method of the robust reliability index is brought forward by interval combination algorithm, so a new uncertainty analysis method for the stability of karst roof under foundation pile based on Info-Gap theory is put forward.This method not only has lower requirement for the message amount of engineering data but also can not know the random distribution shape of uncertain variables, and it is a supplement and improvement for the existing relative research, What’s more, because these uncertain variables are divided into design variables and design parameters in this method to achieve the dynamic analysis of allowable uncertain degree of design parameters under different design variables, thus, the method proposed in this paper has the function of not only passive reply but also active disposal. Finally, in the analysis of practical engineering example, the operating process and application process of the method proposed in this paper are presented and the rationality and feasibility of this method is verified.更多还原