基于FEFLOW的岩溶管道模型构建方法探讨

岩溶管道流模型的刻画一直是岩溶区开展地下水数值模拟研究中的难点所在，基于此，文章以贵州六枝特区某项目为例进行地下水数值模拟研究，探索了在FEFLOW离散特性功能模块下岩溶管道流模型的刻画方式与方法。在详细分析研究区地质及水文地质条件的基础上，对研究区范围、边界、含水层结构等概化，建立了研究区的水文地质概念模型；以ArcGIS软件为辅助，基于有限元法的FEFLOW软件为操作平台，利用区内钻孔资料及野外测算结果，通过软件公式编辑、插值等功能分别获得各层顶底板高程属性，将数据输入FEFLOW后，对模拟区平面三角剖分进而空间离散构建了研究区的三维地质模型；并利用FEFLOW软件的离散特性功能模块，将研究区灰场南部岩溶洼地与岩脚泉间划定为特定区域，建立缓冲区并给予其高特异性，耦合哈根-泊肃叶流体流动公式，在模型中刻画了岩溶管道流模型；最后探讨了特殊地质构造与岩溶管道模型的刻画方式与方法刻画出了符合案例区的三维向斜褶皱地质模型和岩溶管道流模型。 

Application of FEFLOW to the description of karst conduit flow model

For a long time, it has been a challenge to describe the karst conduit flow in the research of groundwater numerical model at karst area. Giving these, this paper chose one item area in Liuzhi special district as an example to carry out the groundwater numerical simulation research, as well as to discuss the approach to depict karst conduit flow model by using FEFLOW software. The study area is situated in the typical karst mountains in Southwest China, and the groundwater mainly occurs in the form of karst conduit flow or karst fissure water in the area. Tectonically, this study area belongs to Rock Feet Syncline and rock stratum is relatively simple. According to field investigation there are some northeast beaded karst depressions in the south of the ash field selected by construction project; and the geophysical exploration has also confirmed the existence of hidden karst conduits. On the basis of a detailed analysis of geological and hydrogeological conditions and a careful examination of the scope, boundary, aquifer structure and etc. of the area, a hydrogeological conceptual model was established. Taking ArcGIS software as the assist and FEFLOW software based on the finite element method as the operation platform, by using borehole data and field measurement results, the elevation attributes of roof and floor in each layer have been acquired through formula editor and interpolation function of the software. After the data input to FEFLOW, a three-dimensional geological conceptual model of the synclines in the study area was established by carrying out the triangle subdivision to yield model area discretion. Through characteristic discrete function of FEFLOW, the karst depressions and rock feet spring in the south of ash field were defined as particular areas. By establishing a buffer zone with high specificity and coupling Hagen-Poiseuille flow equation, the karst conduit flow model was then depicted. The paper discussed the approaches to delineate special geological structure which was involved in the karst conduit flow model. The theory and method used in the study is a new attempt to solve relevant problems associated with establishing numerical model for the karstic aquifer, which may shed light on of the idea of conceptualization and modelling of geologically complex domains, especially the fractured-conduit flow in karst area.