本文選題：濱海含水層 + 數(shù)值模擬�。� 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：海潮引起的海水水位的周期性波動(dòng)必然會(huì)引起下部含水層壓力的變化,這種壓力變化勢(shì)必會(huì)對(duì)含水層地下水動(dòng)態(tài)造成一定的影響,即海潮荷載效應(yīng)。在過(guò)去的60多年里,各國(guó)的許多專家學(xué)者對(duì)海潮引起水位波動(dòng)進(jìn)行了解析研究,其中有很多涉及到這種作用機(jī)制。但是,目前所有的地下水?dāng)?shù)值模擬軟件中,即使是很出名的,如MODFLOW、FEFLOW等軟件,都沒(méi)有考慮這種效應(yīng)。本文運(yùn)用已拓展的數(shù)值模擬程序MARUN進(jìn)行數(shù)值模擬研究。MARUN程序考慮了鹽分對(duì)液體粘度和密度的影響,能模擬非飽和帶空隙介質(zhì)中水流和溶質(zhì)運(yùn)移。拓展后的MARUN程序添加了海潮荷載效應(yīng),本文利用其參照文獻(xiàn)中關(guān)于海潮荷載效應(yīng)的解析模型,考慮了兩種濱海多層含水層系統(tǒng)：第一種含水層系統(tǒng)包括上部潛水含水層、中間的弱透水層以及下部的承壓含水層,其中弱透水層及承壓含水層在海底延伸一段有限距離；第二種含水層系統(tǒng)包括上部的隔水層、下部的承壓層以及在海底露頭處隔水的淤泥覆蓋層,其中隔水層及承壓含水層在海底延伸一段有限距離。模擬了荷載系數(shù)在0-1范圍內(nèi)的幾種典型情況。對(duì)于第一種含水層系統(tǒng),在考慮地下水密度效應(yīng)時(shí),承壓含水層中文獻(xiàn)解析解與本文數(shù)值解水頭波動(dòng)之間的誤差不超過(guò)海潮波幅的0.21%,在弱透水層中的海岸帶附近區(qū)域誤差較大,在弱透水層的其他區(qū)域,數(shù)值解和解析解水頭波動(dòng)吻合情況較好。在第二種含水層系統(tǒng)中,在考慮地下水密度效應(yīng)時(shí),文獻(xiàn)解析解與本文數(shù)值解誤差不超過(guò)海潮波幅的0.12%。海水和地下淡水之間的密度差異必然會(huì)影響地下水動(dòng)態(tài),本文利用數(shù)值模擬程序MARUN,對(duì)比了考慮和忽略密度效應(yīng)兩種情況的數(shù)值解,模擬了單一潛水含水層和復(fù)雜多層含水層兩種類型,分別取不同海灘坡度研究密度效應(yīng)對(duì)水頭波動(dòng)的影響。數(shù)值模擬對(duì)比結(jié)果表明,對(duì)于單一潛水含水層,在潮間帶下部的含水層中,坡度為0.1時(shí),考慮和忽略密度效應(yīng)兩種情況的數(shù)值解之間的最大誤差為2.5%,該誤差隨海灘坡度的增加而增大,當(dāng)坡度達(dá)到0.86時(shí),潮間帶下部含水層中誤差達(dá)到百分之十幾,說(shuō)明在單一潛水含水層中,密度效應(yīng)在影響水頭波動(dòng)的同時(shí)會(huì)受到坡度的影響。對(duì)于多層結(jié)構(gòu)含水層,在不同坡度情況下,弱透水層與承壓含水層中最大誤差均為2.50%,且在水陸界面上達(dá)到,說(shuō)明密度效應(yīng)幾乎不受坡度的影響。
[Abstract]:The periodic fluctuation of the sea water level caused by the sea tide will inevitably lead to the change of the pressure of the lower aquifer, which will inevitably have a certain effect on the groundwater dynamics of the aquifer, that is, the tidal load effect. In the past 60 years, many experts and scholars of various countries have made analytical research on the fluctuation of water level caused by sea tide, many of which are related to this mechanism. However, even well-known software, such as MODFLOWFEFLOW, does not take this effect into account. In this paper, the extended numerical simulation program MARUN is used to simulate the fluid flow and solute transport in unsaturated porous media, considering the effect of salt on the viscosity and density of the liquid. The expanded MARUN program adds the tidal load effect. In this paper, two kinds of coastal multilayer aquifer systems are considered by referring to the analytical model of the tidal load effect in the literature. The first aquifer system includes the upper submersible aquifer. The intermediate weak permeable layer and the lower confined aquifer, in which the weakly permeable layer and the confined aquifer extend a limited distance from the seabed; the second aquifer system includes the upper aquifer, The bottom of the confined layer and the silt cover that separates water at the outcrop of the seafloor, in which the water-isolated layer and the confined aquifer extend at a limited distance from the bottom of the sea. Several typical cases with load coefficient in the range of 0-1 are simulated. For the first aquifer system, when the groundwater density effect is considered, the error between the analytical solution in the confined aquifer and the numerical solution in this paper does not exceed 0.21 of the tidal wave amplitude, and the regional error is larger in the coastal zone near the weak permeable layer. In other regions of the weakly permeable layer, the numerical and analytical solutions are in good agreement with the water head fluctuation. In the second aquifer system, when the groundwater density effect is considered, the error between the analytical solution and the numerical solution in this paper is not more than 0.12 of the tidal wave amplitude. The density difference between seawater and fresh water will inevitably affect groundwater dynamics. In this paper, the numerical solutions of considering and neglecting the density effect are compared by using the numerical simulation program Marun. Two types of submersible aquifer and complex multilayer aquifer were simulated. The effects of density effect on the water head fluctuation were studied with different beach slopes. The numerical simulation results show that for a single aquifer, the slope of the aquifer in the lower part of the intertidal zone is 0.1, The maximum error between the numerical solutions considering and ignoring the density effect is 2.5, which increases with the increase of the beach slope. When the slope reaches 0.86, the error in the lower aquifer of the intertidal zone reaches more than ten percent. It is concluded that in a single aquifer, the density effect will be affected by the slope as well as the water head fluctuation. For the multi-layered aquifer, the maximum error between the weakly permeable aquifer and the confined aquifer is 2.50 at different slopes, and the maximum error is achieved at the water-land interface, indicating that the density effect is almost independent of the slope.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P641;P731.23

【共引文獻(xiàn)】

相關(guān)期刊論文 前3條

1 王學(xué)靜;李海龍;柳富田;王超月;;利用地下水潮汐效應(yīng)估算含水層參數(shù)及預(yù)測(cè)水位變化[J];工程勘察;2013年09期

2 謝瀟;朱文渤;郭海強(qiáng);趙斌;;潮汐與降雨對(duì)濱海濕地地下水位的影響[J];復(fù)旦學(xué)報(bào)(自然科學(xué)版);2013年06期

3 周訓(xùn);曹琴;尹菲;郭娟;王曉翠;張永帥;王黎棟;沈曄;;四川盆地東部高褶帶三疊系地層鹵水和溫泉的地球化學(xué)特征及成因[J];地質(zhì)學(xué)報(bào);2015年11期

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本文編號(hào)：1975378