【摘要】：潛流帶是河流和地下水進(jìn)行物質(zhì)和能量交換的區(qū)域。潛流交換對(duì)河流或地下水質(zhì)及其生態(tài)都有重要影響。本論文以經(jīng)典的EB模型為基礎(chǔ),通過(guò)解析解的方法研究了區(qū)域地下水流動(dòng),潛流帶巖石各向異性,河水位變動(dòng)以及沙丘移動(dòng)等常見(jiàn)因素對(duì)由河床沙丘所引發(fā)的潛流交換的影響(由河床沙丘移動(dòng)產(chǎn)生的潛流交換為沖淤交換)。研究表明:(一)、區(qū)域地下水補(bǔ)給和排泄流動(dòng)影響潛流上升區(qū)和下降區(qū)的混合深度,模擬河流水質(zhì)的瞬時(shí)儲(chǔ)存模型的參數(shù)應(yīng)該考慮區(qū)域地下水補(bǔ)給或排泄的影響;(二)、潛流帶縱向滲透系數(shù)與橫向滲透系數(shù)比值增大,潛流交換量也隨之增加,平均停留時(shí)間趨于零的時(shí)間變短,溶質(zhì)質(zhì)量交換增加;(三)、對(duì)于由河床水位隨時(shí)間波動(dòng)引起的非穩(wěn)定泵吸流,隨著水位波動(dòng)頻率的增大對(duì)潛流帶流場(chǎng)造成的擾動(dòng)越大,潛流交換量增加,平均停留時(shí)間趨于零的時(shí)間變短,溶質(zhì)質(zhì)量交換變大;隨著壓力傳導(dǎo)系數(shù)的減小,潛流交換先增大后減小,平均停留時(shí)間趨于零的時(shí)間變長(zhǎng),溶質(zhì)質(zhì)量交換先增大后減小;(四)、對(duì)于由河床沙丘移動(dòng)引起的非穩(wěn)定沖淤流,隨著河床沙丘移動(dòng)速度的增大對(duì)潛流帶流場(chǎng)造成的擾動(dòng)越大,平均停留時(shí)間趨于零的時(shí)間減小,溶質(zhì)質(zhì)量交換減小;隨著壓力傳導(dǎo)系數(shù)的減小,潛流交換隨之減小,最后趨于一個(gè)定值,平均停留時(shí)間在更短的時(shí)間內(nèi)趨近于零,溶質(zhì)質(zhì)量交換減小。這兩種情況下的非穩(wěn)定潛流,當(dāng)壓力傳導(dǎo)系數(shù)變的更大的時(shí)候,潛流帶的流場(chǎng)都不再發(fā)生改變。
[Abstract]:The subsurface flow zone is the area where rivers and groundwater exchange matter and energy. Subsurface flow exchange plays an important role in river or underground water quality and ecology. Based on the classical EB model, the regional groundwater flow and rock anisotropy in the subsurface flow zone are studied by the analytical solution method in this paper. The influence of some common factors, such as river water level change and dune movement, on the subsurface flow exchange caused by the riverbed dune movement, which is called scour and silt exchange. The results show that: (1) regional groundwater recharge and discharge flow affect the mixing depth of subsurface flow rising and descending zone, and the parameters of instantaneous storage model for simulating river water quality should consider the influence of regional groundwater recharge or discharge; (2) with the increase of the ratio of longitudinal permeability coefficient to transverse permeability coefficient in the subsurface flow zone, the amount of subsurface flow exchange increases, the mean residence time tends to zero, and the mass exchange of solute increases. (3) for the unstable pump which is caused by the fluctuation of river bed water level with time, with the increase of the frequency of water level fluctuation, the greater the disturbance to the flow field of the subsurface flow zone, the more the exchange quantity of the subsurface flow increases, and the time of the average residence time tends to zero becomes shorter. Mass exchange of solute becomes larger; With the decrease of the pressure conduction coefficient, the subsurface flow exchange first increases and then decreases, the mean residence time becomes longer, and the solute mass exchange increases first and then decreases. (4) for the unstable scour and silt flow caused by the moving of the riverbed dune, the disturbance of the flow field in the subsurface flow zone is greater with the increase of the moving velocity of the riverbed dune, the mean residence time tends to zero, and the mass exchange of solute decreases; With the decrease of the pressure conduction coefficient, the subsurface flow exchange decreases, and finally tends to a fixed value, the mean residence time approaches to zero in a shorter time, and the mass exchange of solute decreases. In both cases, when the pressure conduction coefficient becomes larger, the flow field in the subsurface flow zone will not change.
【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】：2017
【分類(lèi)號(hào)】：P641;P339
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本文編號(hào)：2393224