基于Modflow的虎林灌区地下水开采三维数值模拟

MODFLOW- based 3D numerical simulation of groundwater exploitation in Hulin irrigation area

针对地下水开采引起的地面沉降问题,以鸡西市虎林灌区为例,采用国际通用的地下水三维渗流与地面沉降耦合计算软件——Processing Modflow,建立虎林灌区地下水-地面沉降耦合模型。以2014年年均开采量为依据,对2015年的地下水位及沉降进行数值模拟计算,并通过钻孔及室内土工实验分析其沉降机理。结果表明:2015年水位呈现北部及东南部水位高、西部较低,沉降量由中心区向四周逐渐增大的趋势;沉降严重区域土样的天然含水率、密度随深度增加呈现减小的趋势,相对密度随深度变化不明显;土样的塑性指数与其相对密度呈现正相关,变形量与其压力呈正相关,土体的压缩系数和渗透系数与压力呈负相关。

This paper is focused on addressing ground settlement resulting from groundwater exploitation. The research exemplified by a case study of irrigation areas in Hulin in Jixi city involves using Processing Modflow-an internationally accepted coupling calculation software for 3D groundwater seepage and surface subsidence and thereby developing the coupling-model between groundwater and ground subsidence typical of Hulin irrigation area. The study describes a simulation calculation of the groundwater level and subsidence in 2015, according to the annual mean production in 2014 and an analysis of the mechanism behind the settlement by drilling and laboratory soil test. Results show that,in 2015 there is a higher water level in the north and southeast, but a lower water level in the west, with the settlement tending to have a gradual increase from the central area to surrounding areas; the natural moisture content and density tend to decrease due to an increasing depth in the soil samples taken from the area with severe subsidence, but there is no obvious change in relative density; a positive correlation exists between the plastic index and relative density of the soil sample, and between the deformation amount and the pressure, but a negative correlation occurs between the compression coefficient and the osmotic coefficient of the soil on the one hand and the pressure on the other hand.