悬臂支护基坑失稳风险的改进风险矩阵分析方法

基坑失稳风险评价是基坑设计和安全施工的重要环节。首先在深入研究悬臂支护基坑失稳风险事件及其风险因素基础上，建立出综合考虑风险概率和风险后果影响的基坑失稳风险综合分析模型；然后，考虑基坑失稳力学机理及基坑土体物理力学参数的不确定性的区间性特征，引入非概率可靠性分析方法，建立出基坑风险概率的确定方法；同时，引入信息熵理论，建立出可反映专家评价水平的风险后果评价方法，进而建立出悬臂支护结构基坑失稳风险的改进风险矩阵分析方法；最后，通过工程实例分析表明了方法的合理性与可行性。

Improved risk matrix method of instability risk for excavations with cantilever retaining

Instability risk assessment is an important link of design and safe construction of excavations.Firstly,based on a comprehensive analysis of risk events and their risk factors for excavations with cantilever retaining,a comprehensive analysis model of instability risk for excavation engineering is formulated considering the risk probability and risk consequence.Secondly,considering the mechanical mechanism of instability of excavations and the interval uncertainty feature of physical and mechanical parameters of soil,a method to determine the risk probability of foundation instability is presented by introducing the non-probabilistic reliability analysis.Thirdly,based on the information entropy theory,the evaluation method for the risk consequence is formulated,which can reflect the experts’ evaluation level.And the improved risk matrix method of instability risk for excavations with cantilever retaining is developed.Finally,the method is used to analyze the practical engineering,and it is shown that the proposed method is feasible and reasonable.