岩溶发育地质条件下的库区三维渗流场分析及渗控效果评价

Three-dimensional seepage field analysis and seepage control effect evaluation of a reservoir site under karst development geology

我国是世界上岩溶地貌分布较为广泛和典型的国家之一,因而在岩溶发育地质条件下建库筑坝成为坝工界普遍重视的技术难题。库址区的渗流分析和控制评价是大坝设计及运行过程中的一个重要环节,对库址区岩土体及水工建筑物的安全和水库运行的经济合理性有着重要的影响。选取某岩溶发育地质条件下的水库大坝工程,结合工程特点,建立反映主要坝体结构和库址区水文地质特征的渗流分析三维有限元模型,采用饱和-非饱和渗流计算理论计算分析运行期库址区渗流场,并研究库址区坝体、坝基及两岸岩体渗流特性和变化规律,进而对工程所采取的防渗体系的合理性进行评价。结果表明:设计防渗体系能够有效降低库址区地下水位,库址区各部位渗透坡降总体较小,能够满足渗透稳定要求,并且在当前防渗系统作用下,库址区渗漏量得到有效控制。

China is one of the typical countries with a wide range of karst landforms in the world,it has been a technical problem to build a dam under the geological conditions of karst development.The seepage analysis and control evaluation of the reservoir site plays an important role in the process of dam design and operation,and has an important impact on the safety of the rock mass and hydraulic structures in the reservoir site,as well as the economic rationality of reservoir operation.Here,a reservoir dam project under the geological condition of karst development was selected as the research object,combined with the engineering characteristics,a three-dimensional finite element model of seepage analysis was established based on the characteristics of the main dam structure and the hydrogeological conditions of the reservoir site.The saturated-unsaturated seepage calculation theory was used to calculate and analyze the seepage field in the reservoir site during the operation period.In addition,the seepage characteristics and change laws of the dam body,dam foundation and rock mass on both banks of the dam in the reservoir site were studied to evaluate the applicability of the anti-seepage system adopted in this project.The results show that the designed seepage control system in use can effectively reduce the groundwater level in the reservoir site,and the seepage gradient of each part of the reservoir site is generally small,which can meet the requirements of seepage stability.Moreover,under the effect of the current seepage control system,the leakage in the reservoir site is effectively controlled.