基于云模型的地铁施工地表变形风险推理分析

Risks Inference on the Ground Deformation of Subway Tunnel Based on Cloud Model

在地铁盾构施工地表沉降研究中,风险因素具有模糊性和随机性的特点,云模型理论可将自然语言值表示的某个定性概念转换为定量表示,把模糊问题的亦此亦彼性和隶属度的随机性统一起来。本文在建立盾构施工地表沉降事故树的基础上,运用云模型处理专家对风险因素发生概率大小分布范围划分定性与定量的转换关系,通过对云图凝聚性的修正,更加客观、准确地确定了地铁盾构施工引发地表沉降各风险因素的概率分布范围和基本事件的概率值;基于云模型和信心指数实现了定性语言值向定量数值的转换。在此基础上进行模糊事故树敏感性分析,得出盾构施工地表沉降风险的基本事件模糊重要度,由此明确影响大的基本事件,便于针对性制定施工事前地表沉降控制措施。

Risks have the characteristics of vagueness and randomness in study of surface subsidence in subway shield construction. Cloud model theory can transfer natural language that indicates a qualitative concept into a quantitative representation,integrating dual nature and randomness of fuzzy problems. Based on the fault tree of surface settlement,this paper uses cloud model to process the relation of the range of distribution of risk factors which are divided into qualitative and quantitative by experts. Through the correction of cloud cohesion,it can be more objective and accurate to determine the probability values of basic events and the range of distribution of risk factors caused by the subway shield construction; Based on cloud model and confidence index,the transformation of qualitative linguistic value to quantitative numerical is realized. Using the sensitivity of fuzzy fault tree analysis,we can get fuzzy importance degree of each basic event of surface subsidence in subway shield construction,to develop targeted measures for controlling possible surface settlement before construction.