山岭隧道施工期坍塌易发性评价方法研究

Safety risk assessment system is very important during the process of mountain tunnel construction. However, the current theoretical researches are not enough to instruct practise. The current system is problematic due to: 1) insufficient analysis of the existing accidents; 2) evaluation factors are not mutual exclusive; 3) the selection of evaluation factors and their weightings are primarily experiences dependent, which has low precision and low reliability. Taking the evaluation of collapsion possibility as an example, this study combines several methods such as case analysis, geological forecast and rough set theory, and aims to introduce a new safety risk evaluation system. The risk environment and risk factors involved in tunnel collapse are integrated and summarized. A risk assessment index system is established for tunnel collapse. Meanwhile, since the dynamic response parameters in advanced geological prediction indicate some typical geological structure, the sensitive dynamic response parameters are introduced in the assessment index system. The new system could predict the safety level of the tunnels to be constructed by comparing their property similarities with earlier accidents. Finally, attribute reduction, calculation of attribute significance and weight are then performed for risk environment and risk factors of the similar cases, based on the attribute significance and weight theory of rough set, to eventually evaluate the risk independently from experiences. The results will improve the understanding and reliability of safety risk assessment of the tunnel construction, and provide guidelines for future projects.

在山岭隧道施工过程中实施安全风险管理十分重要，然而现有的研究水平严重滞后于工程应用。目前的评估工作存在对事故案例的剖析、推理不够，众多的评价指标间存在包含、冗余关系，评价指标的选取和权重的赋值主要依赖专家经验，存在精度低、可靠性差等缺陷。本课题拟以坍塌事故的易发性评价为例，采用案例推理、超前地质预报、粗糙集理论相结合的研究方法，探索建立新的评价体系及方法。通过对坍塌事故孕险环境和致险因子的剖析，和超前地质预报敏感的动态响应参数的引入，构建新的更完备的评价指标体系。针对待评价隧道对象，索引并提取与其属性特征相似的坍塌案例，通过相似案例间接实现对待评价隧道处理。最后，基于粗糙集的属性重要度、权重理论，对相似案例的孕险环境和致险因子开展属性重要度、权重计算和属性约简，实现基于实际案例而不依赖专家经验和主观赋权的综合评价。研究成果将提高隧道安全风险评估的理论水平和可靠性，对隧道工程建设有重大指导意

山岭隧道施工过程中实施安全风险管理十分重要，然而现有的研究滞后于工程应用。本课题以山岭隧道的坍塌易发性风险评价为例，介绍基于案例推理、超前地质预报和粗糙集理论的新评价方法。首先，基于隧道坍塌案例的剖析，整合、归纳坍塌事故的孕险环境和致险因子，应用层次分析法阐明了山岭隧道坍塌是设计、管理和施工等外在致险因子偶然触发隧道所处环境、地质中孕育着的内在孕险环境的结果，构建坍塌易发性风险评价的指标体系。同时，基于常用的地震波反射法和电磁波反射法，揭示了山岭隧道超前地质预报成果的动态响应参数对典型地质体的指示效应；并将其敏感的动态响应参数纳入坍塌易发性风险评估指标中，构建新的更完备的评价指标体系，实现对掌子面前方一定距离内待开挖隧道的风险超前评价。其次，推导了基于粗糙集的条件信息熵新方法，解决传统方法的属性重要度计算的弊端并将其应用于隧道坍塌易发性风险评估中；然后，针对待评价的隧道对象，对其主要孕险环境和超前地质预报成果进行分析，通过与已有经验案例比对，选取属性特征相似的案例；应用条件信息墒的新方法实现对这些相似案例的孕险环境和致险因子的权重计算和属性约简，间接实现对待评价隧道对象的评价指标的优选和权重确定。最后，将优选后的评价指标和权重应用于模糊综合评价模型，实现待评价隧道的风险评价。研究成果将提高隧道安全风险评估的理论水平和可靠性，对隧道工程建设有指导意义和参考价值。