本文選題：滲流　切入點(diǎn)：地下水位差　出處：《長(zhǎng)沙理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：海岸帶作為人類從事生產(chǎn)活動(dòng)的主要區(qū)域,海岸發(fā)展對(duì)全球經(jīng)濟(jì)起著至關(guān)重要的作用,隨著海岸的不斷開發(fā)利用,全球海岸受到嚴(yán)重侵蝕,目前世界不少地區(qū)趨于通過抽取地下水來保護(hù)岸灘,其原理就是基于地下水滲流對(duì)泥沙運(yùn)動(dòng)和岸灘演變的影響。然而傳統(tǒng)的海岸動(dòng)力研究大多基于不可滲的海灘或者在可滲海灘中忽略滲流作用,因此開展?jié)B流影響下的泥沙運(yùn)動(dòng)和岸灘演變規(guī)律研究具有重要的理論意義和社會(huì)價(jià)值。本研究通過開展波浪水槽實(shí)驗(yàn),研究實(shí)驗(yàn)水深分別為0.4m、0.45m和0.5m情況下結(jié)合橢圓余弦波和孤立波的作用探討不同波浪要素情況下沙質(zhì)斜坡的水動(dòng)力特性,人工降低地下水位以及橢圓余弦波作用下管滲對(duì)沙質(zhì)岸灘剖面變化規(guī)律、泥沙分選規(guī)律以及孔隙水壓力分布的影響。波浪水槽實(shí)驗(yàn)采用1：10單一斜坡概化沙質(zhì)岸灘,選用2種波浪類型、3種實(shí)驗(yàn)水深改變波浪動(dòng)力因素,分別在人工降低地下水位、管滲影響下對(duì)波浪在沙質(zhì)岸灘上傳播過程進(jìn)行觀測(cè),測(cè)量波浪作用后岸灘地形變化、泥沙粒徑組成以及岸灘內(nèi)部孔隙水壓力。實(shí)驗(yàn)結(jié)果表明：采用FFT和HHT理論分析滲流對(duì)能量的時(shí)域和頻域變化特征影響,人工降低地下水位后,近岸區(qū)水流能量較自然滲流減小。橢余波作用下,相對(duì)于自然滲流,人工降低地下水位和管滲促進(jìn)岸灘的沖刷,滲流管在水陸交界面處沖刷最嚴(yán)重,管滲條件下離岸區(qū)泥沙出現(xiàn)細(xì)化,波谷孔隙水壓力平均值增加的幅值大于波峰孔隙水壓力平均值,滲流力促進(jìn)泥沙顆粒起動(dòng)。孤立波作用下,地下水位下降后產(chǎn)生的滲流有利于泥沙淤積；相比于自然滲流,地下水位差增加了岸灘的非飽和度,入滲水流抑制了粗顆粒泥沙起動(dòng),岸灘近岸淤積位置粒徑級(jí)配出現(xiàn)局部粗化。
[Abstract]:Coastal zone, as the main area of human being engaged in production activities, coastal development plays a vital role in the global economy. With the continuous development and utilization of the coast, the global coast has been seriously eroded. At present, many parts of the world tend to protect the shoreline by pumping groundwater. The principle is based on the influence of groundwater seepage on sediment movement and shoreline evolution. However, the traditional coastal dynamic research is based on the impermeable beach or neglecting the seepage in the permeable beach. Therefore, it is of great theoretical significance and social value to study the sediment movement and shoreline evolution law under the influence of seepage. The hydrodynamic characteristics of sandy slopes with different wave elements are studied by combining the effects of elliptical cosine wave and solitary wave under the experimental water depth of 0.4mg 0.45m and 0.5m, respectively. The effects of pipe seepage on the profile variation, sediment sorting and pore water pressure distribution of sandy shoreline under the action of artificial lowering of groundwater level and elliptical cosine wave are studied. The wave flume experiment is based on a single slope of 1:10, which is used to generalize sandy shoreline. Using two kinds of wave types and three kinds of experimental water depth to change the dynamic factors of wave, the wave propagation process on sandy shoreline is observed under the influence of artificial lowering of groundwater level and seepage, and the topographic changes of shoreline after wave action are measured. The experimental results show that FFT and HHT theory are used to analyze the influence of percolation on the variation of energy in time domain and frequency domain, and after artificially lowering the groundwater level, the sediment particle size composition and pore water pressure in shoreline are analyzed. Under the action of elliptical afterwave, compared with natural seepage, artificial lowering of groundwater level and pipe seepage promote shoal erosion, and seepage pipe scour is the most serious at the interface between water and land. Under the condition of pipe and seepage, the sediment in the offshore area is refined, the amplitude of the mean pore water pressure in the trough is larger than the average value of the pore water pressure of the wave peak, and the seepage force promotes the sediment particle to start. Compared with natural seepage, the difference of groundwater level increases the unsaturation of shoreline, and the infiltration water inhibits the starting of coarse sediment. Local coarsening occurs in the grain size gradation of shoreline near shore siltation position.
【學(xué)位授予單位】：長(zhǎng)沙理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P748;P731.22

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本文編號(hào)：1563291