基于岩溶分布分析的突水风险评估模型研究

为实现岩溶突水风险评估的全过程动态修正与管理,一以岩溶发育分布规律为基础,采用半定量分析方法,估计溶洞与隧道在剖面图中的相对位置距离值,二将防突水岩层安全厚度的预测划分为初步估算、二次估计和动态测算3个阶段,每个阶段均采用有效的修正方式,不断获取更加准确且适用的防突岩层安全厚度预测数值。然后,综合考虑防突岩层安全厚度以及爆破开挖扰动深度影响,提出岩溶突水风险概率等级评价标准;通过划分突水量和溶腔高水头压强的等级,提出岩溶突水风险后果等级评价标准;并以二者为基础构建岩溶突水风险等级评估矩阵。最终,构建基于岩溶分布态势与防突岩层厚度的岩溶突水风险评估模型。通过具体工程实例检验,理论结果与实际情况相对比,验证所构建岩溶突水风险评估模型的合理性与可行性。

Study on Karst Water Inrush Risk Assessment Model Based on Karst Distribution Analysis

The purpose of the paper is to realize the dynamic modification and management of the full course of the assessment on the karst water inrush risks. In the paper, first, the distance between the karst caves and the tunnel in the profile map is estimated by means of semi quantative analysis method on basis of the development and distribution rules of the karst; secondly, the prediction of the safe thickness of the karst water inrush resisting rock strata is divided into three stages, i.e., the preliminary estimation stage, the secondary estimation stage and the dynamic calculation stage, for which effective modification methods are adopted so as to obtain more accurate and more appropriate prediction values for the safe thickness of the karst water inrush resisting rock strata; thirdly, the evaluation standard for the probability level of the karst water inrush risks is proposed on basis of the safe thickness of the water inrush resisting rock strata and the disturbance depth of the excavation blasting, the evaluation standard for the consequence level of the karst water inrush risks is proposed by means of classifying the water inrush volumes and the water pressures in the karst chamber, and the assessment matrix for the grades of the karst water inrush risks is established; Finally, the assessment model for the karst water inrush risks based on the karst distribution pattern and the karst water inrush resisting rock strata is established. The comparison and contrast between the theoretical result and the actual conditions in the engineering cases verifies the rationality and feasibility of the karst water inrush risk assessment model. 