虎林灌区地面沉降数值计算与分析

NUMERICAL CALCULATION AND ANALYSIS OF GROUND SUBSIDENCE IN HULIN IRRIGATION AREA

针对鸡西虎林灌区地下水开采过量引起地面沉降问题,以比奥固结理论为基础,结合土体的非线性流变理论,采用三维有限差分软件Processing Modflow,建立了地下水-地面沉降三维全耦合数值模型,运用参数修正后的模型对区域地下水位及地面沉降机理进行了分析及沉降预测。结果表明,整个应力期地面沉降与地下水位变化呈正相关,变化趋势同步性,土体只发生部分回弹变形,存在残余变形;渗透系数,孔隙比及泊松比与地面沉降变化呈正相关性,变化趋势相同,先减小后增大,而后趋于稳定;压缩系数与水位变化呈负相关,参数变化趋势滞后于水位变化;预测到2016~2025年地下水位与地面沉降速率逐步减缓,至2025年中心区地面年均沉降速率已基本上低于15mm/a。

This paper is focused on addressing ground settlement resulting from groundwater exploitation in Hulin Jixi city, based on Biot consolidation theory and combined with nonlinear rheological theory of soil mass, the finite difference software processing modflow was used to establish three-dimensional full coupling numerical model of groundwater-ground subsidence, the mechanism of the groundwater level and ground subsidence was analyzed and the settlement prediction was predicted by the modified model. The results show that a positive correlation exists between land subsidence and the water level variation, and the changing tendency of land subsidence calculated by groundwater seepage is the same as that of water level variation. There exists part of rebound deformation and remain of subsidence. The porosity, hydraulic conductivity and Poisson＇s ratio have the same tendency of decreasing first and then increasing as land subsidence variation, at last, tend to be stable. But a negative correlation occurs between the compression coefficient and water level variation, The parameter change falls behind of water level change. The groundwater level and the ground subsidence rate are predicted from2016 to 2025 Gradually slowed down to 2025 the central area of the average annual settlement rate has been basically less than 15 mm/a.