岩溶突涌水是岩溶地区隧道建设中的主要地质灾害之一,为有效控制岩溶隧道突水涌泥风险、确保隧道建设安全,基于属性数学理论建立了岩溶隧道突涌水危险性评价的属性识别模型。首先,根据隧址区岩溶水文地质及工程地质条件,选取地层岩性、不良地质、地下水位、地形地貌、岩层产状、可溶岩与非可溶岩接触带及层间与层间裂隙等作为属性评价的一级指标,其中不良地质情况分为含水构造、岩溶水系统和断层破碎带3个二级指标。通过对典型岩溶隧道突涌水实例的系统收集与整理分析,采用频数统计法确定一级评价指标所占权重;采用层次分析法构造判断矩阵确定二级评价指标的权重;其次,对评价指标进行属性测度分析,通过构建各评价指标的属性测度函数以计算单指标属性测度及样本综合属性测度;最后应用置信度准则对隧道突涌水危险性进行属性识别。在工程应用中,采用建立的属性识别模型对三峡翻坝高速公路鸡公岭隧道突涌水危险性进行评价,评价结果与现场施工情况吻合较好,为岩溶隧道突涌水危险性评价提供了一种有效途径。
Water inrush is one of the typical geological hazards during tunnel construction in karst area; an attribute recognition model of water inrush risk evaluation is established based on attribute mathematic theory in order to control the water inrush risk and guarantee tunnel eonstruction's safety. Firstly, formation lithology, unfavorable geology, groundwater level, topography and geomorphology, contact zone of dissolvable and insoluble rocks, layer and interlayer fissures are selected as first grade indices of attribute recognition by considering of karst hydrologic and engineering geological conditions; and the unfavorable geology is divided into water-bearing structure, karst water system and fault fracture zone as second grade indices. The weights of first grade indices are determined by frequency statistic method through collecting and collating information of typical water inrush examples of karst tunnels; and the weights of second grade indices are determined by judgment matrix established by analytic hierarchy process (AHP). Then attribute measurement functions are rigorously constructed to compute attribute measurement of single index and synthetic attribute measurement. Lately, the identification and classification of risk assessment of water inrush in tunnels are recognized by the confidence criterion. The water inrush risk of Jigongling tunnel on the line of Fanba expressway is evaluated based on the established attribute recognition model; and the evaluation result agrees well with construction situation, so as to provide an effective method for water inrush risk evaluation of karst tunnels.