可拓理论对复杂条件下岩溶隧道的风险评估

Risk Evaluation of Karst Tunnel under Complex Geological Condition with Extension Theory

岩溶隧道存在突水、突泥(突砂)、洞穴坍塌等风险,而诱发的主要因素有地质情况、地层岩性、含水状况、可溶岩与非可溶岩接触带、地形地貌、岩层产状、层面与层间裂隙、围岩级别等。基于可拓学,运用可拓理论对隧道进行风险评估,利用可拓优度评价法的全面性与稳定性来确定风险因子,并引入熵权法确定各风险指标的权重系数。在物元模型的基础上建立岩溶隧道的风险评估模型,构建指标体系和评估标准;对定性指标予以量化,同时对各指标归一化、无量纲化预处理。对东风隧道风险段进行了评估,风险等级为极高风险(t=4),根据超前预报及现场实际风险反馈,表明可拓评估在岩溶隧道风险等级评估具有较好的适用性。

Lots of risks exist in Karst tunnel, such as water inrush, mud （ or sand ） inrush or cave collapse and so on. Those are mainly caused by complex geological condition, formation lithology, the condition of groundwater, contact zone of lava with non-lava, landform, attitude of rock, layer and interlayer fracture structure in rock mass. With the help of priority degree evaluation method the matter-element model was established, besides, entropy weight analysis method was applied in risk evaluation of Karst tunnel based on extension theory. The index system and evaluation standard were built, risk assessment system was constructed on the matter-element model, as well as the various index system must be normalized and pretreated to dimensionless one. Risk of Dongfeng Tunnel segment was evaluated, the risk level was the highest （ t = 4 ）, according to information from geological forecast and feedback of Dongfeng Tunnel, the extension assessment in risk level evaluation is suitable to karst tunnel.