软岩隧道大变形事故致灾因素耦合分析

Coupling analysis on disaster-inducing factors for large deformation accidents in soft rock tunnels

为减少专家主观判断对软岩隧道大变形事故评估的影响,提出一种从事故出发逆推事故致灾因素耦合机制的方法。在调研69个软岩隧道施工大变形事故案例的基础上,分析大变形事故的主要致灾因素及其在69个案例中的出现频率;围绕排序前4的主要致灾因素及其在案例中的关联关系,基于系统动力学理论研究不同致灾因素的耦合路径与耦合过程,建立基于N-K模型的致灾因素耦合模型,计算软岩隧道大变形事故致灾因素耦合关联值,在对耦合关联值排序后,得到大变形事故致灾因素耦合影响性序列。结果表明:软岩隧道大变形事故的致灾因素耦合影响性排序依次为:围岩岩性、地下水、地应力和支护强度的四致灾因素耦合>围岩岩性、地下水和地应力三致灾因素耦合>地下水和地应力双致灾因素耦合;虽然地下水与地应力是双因素耦合,但会产生比一些三致灾因素组合更大的耦合值,施工前后应予以特别关注和控制。

In order to reduce influence of experts’ subjective judgment on evaluation of large deformation accidents in soft rock tunnels,a reverse analysis method is proposed to study coupling mechanism of disaster-inducing factors. Based on investigation into 69 cases,main disaster-inducing factors and their frequency rates were analyzed. Then,according to the first 4 major factors and theirs correlation,a N-K model-based coupling model of all factors was established by studying their coupling paths and coupling process via using system dynamics theory. Finally,their coupling correlation values were calculated and ranking of coupling influence was obtained in accordance with the values. The results show that the order of their coupling influence goes as coupling of four factors, surrounding rock lithology, groundwater,geostress and support strength > that of three,surrounding rock lithology,groundwater and geostress >coupling of two,groundwater and geostress. Although groundwater and geostress are two factors coupling,they produce bigger coupling value than that of three factors,so they should be paid special attention and well controlled before and after construction.