湖北宜都磷石膏集中库区岩溶水文地质条件研究

Karst Hydrogeological Conditions of the Phosphogypsum Concentrated Reservoir in Yidu,Hubei Province

建立磷石膏集中库,以堆填的方式处理解决磷工业废弃物是目前的主要方法,而磷石膏集中库的建立对库区水文地质条件有着极高的要求。为避免库区中磷石膏发生泄露对当地地下水环境造成污染以及为该库的实际工程建设与设计提供参考依据,以湖北省宜都市枝城镇六里冲村的磷石膏集中库项目为例,综合利用野外水文地质调查、地球物理勘探、岩溶地下水示踪试验等方法,查明该地区的水文地质条件,采用Qtacer2软件获取水文地质参数,分析研究区岩溶地下水流向及岩溶含水介质结构特征。野外基础地质调查发现库区北部(初期坝处)发育一具有走滑性质的逆断层构造(F2),其是库区岩溶发育方向的主控因素;地球物理勘探确定了沿淹水淌断裂发育的岩溶区存在着地下水流径通道;示踪试验数据表明:库区地下水流速缓慢,存在着由淹水淌断裂控制的地下水主流径带,方向为NE70°;分析示踪剂浓度历时曲线特征得出库区岩溶发育程度不均一,岩溶发育特征为裂隙、单一小型管道、局部溶洞并存,具有非均质各向异性特征;基于Qtacer2数据分析,估算出水力参数(包括弥散系数、纵向弥散度、摩擦系数、雷诺兹数、舍伍德数、施密特数)。研究成果对库区的选址、建设以及对当地岩溶含水层水资源保护提供了依据。

At present,it is the main method to establish a phosphogypsum centralized reservoir to dispose phosphorus industrial waste by landfill,but the establishment of a phosphogypsum centralized reservoir has extremely high requirements on the hydrogeological conditions of the reservoir area.In order to avoid the leakage of phosphogypsum polluting the local groundwater environment and provide a reference for the actual construction and design of the reservoir as well,taking the phosphogypsum centralized storage project in Liulichong Village,Zhicheng Town,Yidu City,Hubei Province as an example,a field hydrogeological survey,geophysical exploration,karst groundwater tracer test and other methods were comprehensively used to find out the hydrogeological characteristics of the sample area.In addition,Qtacer2 software was used to obtain hydrogeological parameters,which contributed to analyze flow direction of karst groundwater and the structural characteristics of the karst water-bearing medium in the study area.It is found that there is a reverse fault(F2)in the northern part of the reservoir area,which is the main controlling factor of karst development direction in the reservoir area.It is confirmed by geophysical exploration that there are underground flow channels in the karst area.The tracer test data show that the groundwater flow velocity in the reservoir area is slow and there exists a groundwater main runoff zone,controlled by F2 fracture,whose direction is NE70°.By analyzing the characteristics of the tracer concentration duration curve,it is found that the degree of karst development in the reservoir area is uneven,which is characterized by the coexistence of fissures,single small pipelines,and local karst caves,having the characteristics of heterogeneity and anisotropy.Based on the analysis of Qtacer2 data,the hydraulic parameters(including dispersion coefficient,longitudinal dispersion,friction coefficient,Reynolds number,Sherwood number,Schmidt number)were estimated.The research results provide a basis for the site selection and construction of the reservoir area and the protection of water resources.