中文摘要：

研究目的：西南山区隧道进出口段往往位于沟谷，地形切割强烈，洞口仰坡易发生崩塌落石灾害。为评价落石灾害风险，本文建立新的隧道洞口段危岩落石风险的综合评估流程以及多指标综合评估模型，克服以往确定指标权重时人为因素影响较大的缺陷，为今后隧道洞口坡段落石灾害治理决策、落石计算和防治工程等设定风险等级提供依据。研究结论：（1）将可拓学理论引入隧道洞口危岩落石风险评估中，建立了隧道洞口危岩落石风险的可拓综合评估流程，构建了落石风险的多指标可拓综合评估模型；（2）对定性指标做定量化处理并对评价指标进行归一化处理，使得评估指标具有可比性，并提出用简单关联函数确定各指标权重；（3）构建了隧道洞口危岩落石风险分级的物元可拓模型，将落石风险等级定为极低风险（Ⅰ）、低风险（Ⅱ）、中等风险（Ⅲ）、高风险（Ⅳ）与极高风险（Ⅴ）五类，通过工程实例验证并利用层次分析-模糊数学综合评价法进行对比，验证了该评价模型的评估结果是合理的、可行的；（4）本研究结果可为落石风险评估提供一种新的思路。

英文摘要：

Research purposes： The extrance and exit sections of tunnels constructed in southwestern are always located in valley. The terrain cutting is intense and the rockfall disasters are common at the heading slope. To evaluate the rockfall risk, flow chart of extension assessment of rockfall risk was established and multi - index extensive comprehensive evaluation model was firstly built and then used to determine factor weight for avoiding human subjective effect, to provide the basis of rockfall hazard management, rockfall calculation and prevention project. Research conclusions：（ 1 ） The extension theory was used in the rockfall risk evaluation. Furthermore, flow chart of extension assessment of rockfall risk was established and multi - index extensive comprehensive evaluation model was built. （2） Some main influencing factors with non - dimension were preprocessed and a simple correlation functions was proposed to make evaluation index comparable. （3） Rockfall risk was classified into （ Ⅰ ） very low risk, （ Ⅱ ） low risk, （ Ⅲ ） medium risk, （ Ⅳ ） high risk and （ Ⅴ） very high risk. The result was validated using a case study and compared to the result got from AHP - Fuzzy mathematics model, which shows the evaluation model is feasible. （4） The results of this paper can provide a new method for rockfall risk evaluation.