Abstract: Based on a comprehensive analysis of the causes to accidents in gasbearing tunnel works, five important indicators were determined to be main risks, which are the stratum lithology, the geological structure, the coal seam thickness, the depth of tunnel and the hydrogeological condition and which would have a great effect on the construction risk of the gasbearing tunnel. According to the five indicators' values, the risks were classified into five different levels during gasbearing tunnel works; And then a Fisher Discrimination Analysis model and its regularization evaluation procedure were built for risk level assessment during tunneling works. 23 previous gasbearing tunnel risk samples were studied and reviewed and corresponding risk classification function was gained. Finally the risk level of 20 gasbearing tunnels were verified with test and the test results coincide with reality. FDA method has the robust and reliable generalized evaluation computing capacity with low error rate of judgment in safety assessment and high general judgment capacity thus it can be extensively applied in risk assessment during construction of complicated engineering system of same type.

Key words: tunnel engineering;gasbearing tunnel, construction period, risk assessment, FDA method

摘要： 在综合分析国内外瓦斯隧道施工事故的基础上，确立了地层岩性、地质结构、煤层厚度、隧道埋深及水文地质条件等5类指标为影响瓦斯隧道施工期风险的关键主因素，由此将瓦斯隧道施工期风险划分为5个等级；然后，建立了瓦斯隧道施工期风险等级评价的FDA法评价体系及其正规化评价流程，并采用23个瓦斯隧道先验风险样本对其进行学习和回判，获得了相应的风险判别函数；最后，对我国20个瓦斯隧道施工期风险等级进行了验证性评价，所得结果和实际相符。FDA法具有稳健可靠的泛化评价计算能力，用于安全评价时误判率低、综合判别能力强，可在同类复杂系统工程施工期风险评价中推广应用。

关键词: 隧道工程, 瓦斯隧道, 施工期, 风险评价, FDA法