利用泉水长观资料计算降水入渗系数——以务川自治县大竹园铝土矿区岩溶充水矿床为例

务川自治县大竹园铝土矿区为高山台地向斜正地形,岩溶充水矿床,水位埋藏较深,大气降水是地下水的唯一补给源,北、东、西为陡崖或陡坡,崖脚为矿系和隔水层,沿陡崖上部边缘分布一条开口向西的地表分水岭,形成完整的水文地质单元,地下水在向斜内由东向西汇集于梅古洞排泄。铝土矿层直接顶板梁山组(P_2l)页岩,厚度小,不连续,其上部茅口栖霞组(P_2m+q)灰岩强含水层与矿层直接接触,并且岩溶管道发育。因此,计算矿坑涌水量的方法用水均衡法较为恰当,即利用泉水观测资料计算入渗系数,从而达到预测矿坑涌水量、评价含水层富水性的目的。

Calculation of infiltration coefficient of precipitation based on long-term observation data of spring water:a case study of ore deposit bearing karst water in Dazhuyuan bauxite mining area in Wuchuan

Dazhuyuan bauxite mining area in Wuchuan Autonomous County is a positive landform of mountain platform syncline.The deposits are ore deposits filled with karst water with deep depth of water level.At-mospheric precipitation is the only recharge source of the ground water.In the north,east and west there are escarpments or steep slopes.Metallogenic series and aquiclude occur on the foot of escarpments.A surface watershed is distributed along the upper edge of escarpments with an opening to the west,and forms a com-plete hydrogeological unit.The ground water in the syncline runs from east to west and collects at Meigudong for discharge.The bauxite layer directly touches the thin and discontinuous roof of shale of Liangshan For-mation (P2 l ),and the strong aquifer above of limestone of Maokouqixia Formation (P2m +q )is in direct contact with ore bed,while the karst pipelines are well developed.Therefore,it is more appropriate to apply the water balance method in terms of calculating the water inflow in the mine.The observational data of spring water is used to calculate infiltration coefficient,so as to predict the water inflow in the mine and to evaluate the water yield property of the aquifer.