基桩桩端岩溶顶板稳定性模糊能度 可靠性分析方法

 基于岩溶区基桩桩端岩溶顶板稳定性影响因素取值的随机性、模糊性以及区间性特征，首先，采用三角模糊数表示计算参数取值可能性分布，以此为基础建立出同时考虑抗冲切、抗剪与抗弯作用的桩端岩溶顶板稳定性模糊极限平衡分析模型；其次，综合运用模糊数学理论、岩体质量分类指标RMR以及Hoek-Brown经验强度准则建立计算参数三角模糊数确定方法，并运用截集技术与区间数运算规则计算相应的安全系数模糊集；再次，在探讨功能函数之合理确定方法基础上，采用模糊能度可靠性理论，提出基桩桩端岩溶顶板稳定性模糊能度可靠性分析方法；最后，通过工程实例分析表明该方法的合理性与可行性，其为基桩桩端岩溶顶板稳定性分析与评价提供了一种新的不确定性分析方法。

FUZZY POSSIBILISTIC RELIABILITY ANALYSIS METHOD FOR STABILITY OF KARST ROOF UNDER PILE TIP

The values of factors that affect the stability of karst roof under pile tip in karst area have the characters of randomicity，fuzziness and interval features. So，triangular fuzzy numbers are firstly used to express the calculating parameter value¢s distributions of possibility. They can reflect the uncertainty when determining the parameters. Based on these fuzzy numbers，the fuzzy limit equilibrium analysis model of karst roof under pile tip is presented，which can consider the action of punching and shearing，shearing and bending effects at the same time. For analysis，the method to determine triangular fuzzy numbers is proposed by comprehensive application of fuzzy mathematics theory，rock mass rating index RMR and Hoek-Brown empirical strength criterion. And level- sets technique and interval number algorithm are introduced to calculate the corresponding fuzzy numbers of the safety factor with the triangular fuzzy numbers and fuzzy limit equilibrium analysis model. Then，the performance function is suggested to evaluate the stability of karst roof under pile tip. The fuzzy possibilistic reliability analysis method for stability of karst roof under pile tip is finally put forward. This method is proven to be rational and feasible by case study，and it provides a new uncertainty analysis method for stability evaluation of karst roof under pile tip.