山东福山铜矿岩溶裂隙水充水矿井涌水量预测

Prediction of water inflow in karst-fracture of Fushan copper mine,Shandong Province,China

福山铜矿位于山东省烟台市,围岩主要是大理岩,岩溶裂隙水为矿床直接充水水源。在分析研究区水文地质条件、岩溶发育特征和地下水流态的基础上,建立了地下水三维渗流模型,模型考虑了地下水在三个主渗流方向上的各向异性,将疏干巷道概化为排水沟,针对金属矿床开采水位降深大,边界流量随着降深的增大而增加,采用通用水头边界,随着降深的变化边界流入量依据水位值计算得到。利用群孔抽水试验资料和长期观测资料对模型进行识别和验证,最终对矿井疏干排水量和不同年份的正常涌水量进行预报,模拟结果为-80m、-200m、-300m、-400 m和-450 m水平平水年正常涌水量分别为7 500 m^3/d、14 060 m^3/d、28 070m^3/d、37 200m^3/d和41 600m^3/d。从岩溶发育特征和地下水流动特征看,在这类岩溶地区建立地下水三维渗流模型是可行的。

Fushan copper mine is located in Fushan district,a hilly area in Yantai City,Shandong Province.Geologically,the region is composed of the lower Proterozoic Fenzishan group and Quaternary deposits,with lithology of the former mainly characterized by metamorphic rocks as marble which forms the wall rock of the mine.Karst landscapes are not fairly developed in the study region where,the major karst morphologies are corrosion fractures and pores.There are two type of aquifers,of which the fractured rock aquifer comprises mica schist intercalated with tremolite marble of the lower of Gangyu Formation and karst-fractured one consists of silicate marble and graphite marble of the upper of Jutun Formation.The ore body is mainly located in the lower of Gangyu Formation and the upper of Jutun Formation at the elevations above -450m.In case of the large differences in lithologies,fractures development,groundwater storage and the permeability of aquifer media,the aquifer was conceptualized as a double-layered structure model,in which the parameter zones were accordingly yielded.Taking the mine dewatering with large drawdown and large discharge into account,a three-dimensional conceptual and anisotropic groundwater flow model was thus established.In this model,boundary conditions of the study area are controlled by regional faults,which can be conceptualized as confining and weak permeable boundaries.And the general head boundary was also used,so that the calculation of lateral inflow came from the change of water level to the weak permeable boundary.Meanwhile,the dewatering tunnel was generalized as drainage ditch.As a result,the total model area is 9.87km^2;and the hydrogeological conceptual model of the study area is regarded as a homogeneously anisotropic,doubledeckered and 3 Dconfined unsteady flow unity.On this basis,the numerical modelling for the groundwater seepage could be performed,which was examined and validated by using the data derived from multiple hole pumping tests and the long-term borehole observation.The drainage water inflow of the mine and normal water inflow in different years were predicted.The results showed that the drainage water inflow were 10,200m3/d,17,400m3/d,26,450m3/d,47,300m3/d and 46,400m3/d,respectively,at the -80 m,-200 m,-300 m,-400m and -450 mlevels,while normal water inflow were 7,500m3/d,14,060m3/d,28,070m3/d,37,200m3/d and 41,600m3/d,respectively.In all,it was feasible to establish the three-dimensional model of groundwater seepage in the study area according to the characteristics of karst development and groundwater flow.Meanwhile,the dewatering tunnel was generalized as drainage ditch and the general head boundary was used in the model,which make the conceptual model more reasonable.