基于Visual MODFLOW的垃圾填埋场阻隔墙设计及效果评估

为了探究阻隔墙在地下水污染场地中的应用效果,以四川省某城市垃圾填埋场为例,选取Cd2+为污染物,通过对水文地质条件的调查,设计了特定条件下阻隔墙的结构、位置以及规模。通过解析法计算了阻隔墙的服役年限,并采用MODFLOW和MT3D模块模拟了设置阻隔墙前后地下水中Cd2+污染羽的分布,分析了阻隔墙对地下水中Cd2+的阻隔效果。结果表明:该阻隔墙为漏斗导水门式垂直阻隔墙。在设置厚度为1 m,选取GB/T 14848—2017《地下水质量标准》Ⅲ类标准作为击穿标准时,阻隔墙的服役年限为12.51年。在污染场中,阻隔墙会吸附地下水中的Cd2+,并减弱阻隔墙上下游间的水力联系,进而实现对地下水中Cd2+的有效阻隔。

DESIGN AND EFFECT EVALUATION OF THE BLOCKING WALL IN LANDFILL BASED ON VISUAL MODFLOW

In order to study the application effect of the blocking wall in a groundwater contaminated site, a city landfill in Sichuan province was taken an example and cadmium was selected as the target pollutant. The structure, location and scale of the blocking wall under specific conditions were designed through investigating hydrogeological conditions. The service life of the blocking wall was calculated by analytic method. MODFLOW and MT3D modules were used to simulate the distribution of cadmium pollution plume in groundwater before and after the blocking wall was set up, and the barrier effect was analyzed. The results showed that the blocking wall was a vertical barrier with funnel gate. The service life of the blocking wall was 12.51 years, under the condition that the thickness was set as 1 meter and Class Ⅲ groundwater quality standard was selected as the breakdown standard. In the contaminated field, cadmium would be absorbed by the blocking wall, and the hydraulic connection between the blocking wall and the downstream would be weakened, thus cadmium could be effectively blocked in groundwater.