海潮引起初始水位倾斜的滨海承压含水层地下水位 变化的数值模拟

海潮波动可以引起海岸带地下水位发生波动。建立了基于有限差分法的滨海地区一维承压含水层地下水运动数值模型。将潮汐波动概化为正弦波,模拟了滨海地区地下水位随潮汐波动的变化。通过与初始水位水平的承压含水层水位变化的比较表明,受海潮影响的滨海承压含水层地下水位与海潮有相似的波动特征,但变幅减小,受海潮的影响程度与离海岸的距离有关,随着离海岸距离的增加,地下水位的变幅及潮汐效率呈负指数函数衰减,但比前者变化程度稍缓,地下水位对海潮的滞后时间随距离呈线性增加。     

定水头补给半无限带状含水层矿坑涌水量评价

通过对广西某石灰岩矿区水文地质条件的分析,对该水文地质单元的水文地质模型进行概化,推导出了定水头补给半无限带状含水层中完整井流公式,并运用该公式对开采条件下矿坑涌水量作了评价。最后,运用传统的逐个干扰井叠加法对该公式的评价结果进行验证,结果表明,当映射叠加次数足够多时,其计算结果极为相近。但就其计算方法而言,映射叠加方法较为繁琐,而运用该公式计算则显得较为方便。     

Analytical approach for time‐dependent groundwater inflow into shield tunnel face in confined aquifer

Prediction of time‐dependent groundwater inflow into a shield tunnel is a significant task facing engineers. Published literature shows that there is no available method with which to predict time‐dependent groundwater inflow into a tunnel. This paper presents a prediction approach for time‐dependent groundwater inflow into a tunnel in both anisotropic and isotropic confined aquifers. The proposed solution can predict groundwater inrush from the tunnel cutting face. To obtain the time‐dependent groundwater flow quantity, the concept of a horizontal‐well pumping test based on the theory of a point source is adopted. Multiple factors, eg, drawdown, thickness of aquifer, conductivities, and specific storage, are taken into account. Both groundwater inflow to the cross section of a tunnel face in the y‐z plane and total tunnel inflow are obtained. Based on the proposed approach, the time‐dependent groundwater inflow to a tunnel can be classified as either a uniform or non‐uniform flow. The proposed approach is applied to analyse groundwater inflow of 2 field cases: (1) Metro line No. 7, Guangzhou City and (2) an underground tunnel in Huizhou, Guangdong Province. Results show that the proposed method can predict the measured values, and drawdown‐related curves are also derived. In addition, the calculated results also reveal that the effect of hydraulic conductivity k_z on the total groundwater inflow differs from that of hydraulic conductivities k_x and k_y and the thickness of the aquifer.     

越流区开采条件下承压含水层易污染性机理研究——以单井开采为例

地下水易污染性分析是合理开发利用地下水资源、保护地下水环境的一项重要的基础性工作.长期以来针对潜水含水层易污染性的研究进行的较为深入,而对承压含水层易污染性的研究较为少见.同时,易污染性评价方法又以经验方法为主,受人为主观因素影响较大,因此需要通过对承压含水层污染机理进行研究,以减少人为主观因素对评价结果的影响.本文以单井开采承压含水层为例,通过分析承压含水层受污染的原因,以单位面积上越流补给量占开采量的比重为承压含水层易污染性指数,在建立越流区承压水向完整井稳定运动的微分方程的基础上,得到易污染性指数的解析表达式,并分析了各参数对易污染性的影响,使承压含水层易污染性评价有了一定的理论依据,对合理开发利用承压含水层有一定的指导意义.