海潮引起的滨海地区地下水位波动的研究

发布时间：2018-01-13 18:00

本文关键词：海潮引起的滨海地区地下水位波动的研究　出处：《中国地质大学(北京)》2016年硕士论文　论文类型：学位论文

【摘要】：滨海地区是人类生产生活密集的地区,海洋与地下水之间的补排关系直接影响着滨海地区的地下水资源量与以及地下水的类型,滨海地区的地下水动态资料直接反映了海洋与地下水之间的相互作用。研究区位于广西省北海市海城区北海岸,该区地下水埋藏类型主要是潜水和三层承压水,该滨海松散孔隙介质多含水层越流系统通过天窗、弱透水层发生密切的水力联系。该地区地下水动态主要海潮的影响。本文利用6个观测孔和海潮6个月的野外观测资料研究了海潮引起的滨海地区地下水波动特征,主要包括相似性、周期性、滞后性、衰减性,另外本文拟合预测了水位波动曲线以及求取了承压含水层储水系数与导水系数的比值。研究结果显示地下水位波动与海潮波动具有很强的相似性;利用谱分析法得到海潮波动与地下水波动具有三个基本相同的周期,近似值分别是341 h(即14.2d)、24.6 h、12.3 h;通过海潮与观测孔水位的互相关系数图得到六个观测孔滞后海潮的时间,观测孔SK1-1、SK1-2、SK1-3、SK1-4、SK2、SK3滞后时间分别为2.75 h、2.5 h、2.5 h、4 h、5.5 h、7 h,滞后时间与距海岸距离大体呈线性关系,近似表达式为xt_L=0076.0(L_t/h滞后时间,x/m距海岸距离);6个观测孔的潮汐效率分别为0.0926、0.1268、0.1596、0.0509、0.08、0.05,潮汐效率随距离大体上呈负指数函数衰减,近似表达式为TE-e~(-0.004x)=(TE为潮汐效率)。用线性方程拟合预测趋势变化,用傅立叶级数拟合排除趋势项之后的数据,二者加和即为数学模型,结果表明该数学模型能较好地拟合预测波动曲线;本文提出了三种求解滨海含水层储水系数与导水系数比值的方法,即一个观测孔、两个观测孔、多个观测孔时的求解方法,统称为潮汐法。并对6个观测孔进行了实例应用,求得北海承压含水层储水系数与导水系数比值大约在0.39×10~(-6)~5.25×10~(-6)d/m~2之间。
[Abstract]:Coastal area is a region where human beings are producing and living intensively. The relationship between ocean and groundwater directly affects the quantity of groundwater resources and the types of groundwater in coastal areas. The groundwater dynamic data of coastal area directly reflect the interaction between ocean and groundwater. The study area is located on the north coast of Beihai City, Guangxi Province. The groundwater burial types in this area are mainly phreatic water and three-layer confined water. The seashore loose porous media multi-aquifer overflowing system passes through the skylight. There is a close hydraulic relation in weak permeable layer. The effect of main sea tide on groundwater dynamics in this area is studied. The fluctuation of groundwater in coastal area caused by sea tide is studied by using the field observation data of 6 observation holes and 6 months of ocean tide. Sign. Mainly include similarity, periodicity, lag, attenuation. In addition, the curve of water level fluctuation and the ratio of water storage coefficient to water conductivity coefficient of confined aquifer are obtained by fitting and forecasting. The results show that the fluctuation of groundwater level is very similar to the fluctuation of sea tide. The results of spectral analysis show that there are three similar periods for tidal wave and groundwater fluctuation, and the approximate values are 341h (i.e. 14.2dU 24.6 h) and 12.3 h (P < 0.05). Based on the correlation figure between the tide and the water level of the observation hole, the time of lag of the tide in the six observation holes is obtained, and the observation hole SK1-1 / SK1-2 / SK1-3 / SK1-4 / SK2 is obtained. The lag time of SK3 is 2.75 h ~ 2.5 h ~ (2.5 h) ~ (2.5 h) ~ 4 h ~ 4 h ~ (5.5) h ~ (-1) 7 h, and the lag time is approximately linear to the distance from the coast. The approximate expression is xt_L=0076.0(L_t/h lag time x / m distance from coast. The tidal efficiency of the six observation holes is 0.0926 ~ 0.1268 ~ (0.1596) ~ 0.050 ~ (9) ~ 0.08 ~ 0.05, respectively, and the tidal efficiency decreases with the distance by a negative exponential function. The approximate expression is that TE-e~(-0.004x)=(TE is the tidal efficiency. The linear equation is used to predict the trend change, and the Fourier series is used to fit the data after excluding the trend term. The addition of the two models is the mathematical model, and the results show that the mathematical model can fit the predicted fluctuation curve well. In this paper, three methods to solve the ratio of water storage coefficient and water conductivity coefficient of coastal aquifer are presented, that is, one observation hole, two observation holes and more than one observation hole. It is called tidal method in general, and is applied to 6 observation holes. The ratio of the water storage coefficient to the conductivity coefficient of the confined aquifer in the North Sea is about 0.39 脳 10 ~ (-1) ~ (-6) ~ 5.25 脳 10 ~ (-1) ~ (-1) d / m ~ (2).
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P641.2;P731.2

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