【摘要】：淡水資源的短缺已成為制約我國經(jīng)濟發(fā)展的一個瓶頸。華北平原淺層咸~微咸水資源豐富,分布較廣,而且具有埋深淺、補給快、易開采等特點。咸水資源作為非常規(guī)水源也應(yīng)該得到重視。為了更科學(xué)合理的開發(fā)利用內(nèi)陸淺層咸水,對于其成因機制及演化規(guī)律的研究顯得尤為重要。本文以內(nèi)陸平原淺層咸~微咸水為研究對象,從地下水動力場和水化學(xué)場兩個方面,研究了內(nèi)陸淺層咸水的動態(tài)變化特征,并分析其成因機制,進而揭示其演化規(guī)律。本文以內(nèi)陸黃泛區(qū)濟陽縣典型咸水區(qū)為例,在查閱國內(nèi)外相關(guān)文獻的基礎(chǔ)上,采用野外調(diào)研、鉆探的方法手段,查明了研究區(qū)地質(zhì)、水文地質(zhì)條件;在野外試驗如抽水試驗、注水試驗、示蹤試驗等與室內(nèi)咸淡水驅(qū)替試驗相結(jié)合的基礎(chǔ)上,研究了內(nèi)陸淺層咸水形成的水動力影響機制;根據(jù)淺層咸水水化學(xué)組分及水化學(xué)類型分布規(guī)律,運用數(shù)理統(tǒng)計、Piper三線圖和離子比例系數(shù)等方法,系統(tǒng)地分析了濟陽淺層地下水水化學(xué)場時空分布規(guī)律;在此基礎(chǔ)上,探討了淺層咸水的形成與地下水循環(huán)徑流過程中各種水巖作用的內(nèi)在聯(lián)系;最后利用水文地球化學(xué)模擬軟件PHREEQC,選取研究區(qū)三個典型地下水滲流路徑進行反向水文地球化學(xué)模擬,并對模擬結(jié)果分析探討,揭示了淺層咸水成因機制及演化規(guī)律。本文通過上述分析研究,得出以下結(jié)論:(1)內(nèi)陸黃泛平原區(qū)淺層咸水位于古河道之間的徑流滯緩區(qū),埋深淺,地下水動態(tài)為典型的“氣象-蒸發(fā)型”,野外試驗揭示了研究區(qū)水力坡度較小,約為0.17‰,徑流條件差,地下水循環(huán)交替強度較差的特點,粘土礦物含量高,有利于鹽分的積累。地下水礦化作用顯著,這對內(nèi)陸咸水體的形成起到?jīng)Q定性作用。(2)室內(nèi)咸淡水驅(qū)替試驗說明,滲流液的鹽度和pH對含水介質(zhì)的滲透性具有明顯的影響。隨著鹽度增加和pH的減小,滲流場的滲透系數(shù)呈減小的趨勢,pH=7.4時滲透系數(shù)突降。滲透性能降低,進一步削弱了地下水的徑流條件,有利于鹽分的聚集。這與咸淡水驅(qū)替過程中復(fù)雜的水文地球化學(xué)作用息息相關(guān)。不同尺度的室內(nèi)試驗還揭示了尺度效應(yīng)對水化學(xué)組分的影響,溶質(zhì)遷移具有遲后效應(yīng)。(3)6050組野外監(jiān)測數(shù)據(jù)表明,降水和地下徑流對咸水體的水平擴散影響較小,內(nèi)陸咸水水質(zhì)動態(tài)相對穩(wěn)定,總體上符合地下水溶質(zhì)含量從補給區(qū)-徑流區(qū)-排泄區(qū)越來越高,水化學(xué)類型越來越復(fù)雜的分布特征,并呈現(xiàn)出明顯的分帶性。(4)內(nèi)陸淺層地下水水化學(xué)類型復(fù)雜多樣,既有溶濾成因,也有大陸鹽化成因。濟陽咸水主要是大陸鹽化成因咸水。介于1.0~2.0的γNa/γCl比值以及大于4的γSO4/γHCO3比值揭示了研究區(qū)水化學(xué)類型的形成與溶濾作用、蒸發(fā)濃縮作用具有緊密聯(lián)系。(5)根據(jù)112組水質(zhì)測試資料結(jié)果表明,濟陽地區(qū)淺層地下水水化學(xué)類型分為42類。不同地下水流動系統(tǒng)的地下水水位動態(tài)和水質(zhì)的差異性,及其徑流循環(huán)條件的差異性,導(dǎo)致其經(jīng)歷的水文地球化學(xué)作用類型和程度不同,這是形成復(fù)雜水化學(xué)類型根本原因。隨地下水逕流途徑的加長,淺層地下水的TDS增高,高礦化的Cl·SO4-Mg·Na·Ca型和Cl·SO4-Na·Mg型淺層咸水,呈點狀零星分布于內(nèi)陸地區(qū)。(6)內(nèi)陸咸水的形成與演化受水動力交替強度、溶濾作用、蒸發(fā)濃縮作用、離子交替吸附作用及水-巖作用的影響。水文地球化學(xué)反向模擬表明,內(nèi)陸淺層咸水演化過程中,沿不同的地下水滲流路徑,影響其水化學(xué)組分形成的主導(dǎo)水化學(xué)作用不同,但并不是單一的某種水文地球化學(xué)作用促成的。總之,內(nèi)陸淺層咸水的演化在徑流途徑上具有分帶性,同時受徑流條件影響,內(nèi)陸淺層咸水演化緩慢且漫長。綜上,內(nèi)陸淺層咸水水化學(xué)特征變化取決于地形、氣象、沉積環(huán)境、水動力條件、水文地球化學(xué)作用等多種原因。氣象、地層巖性、地下水徑流途徑與循環(huán)深度、水文地球化學(xué)作用共同控制內(nèi)陸淺層鹽化咸水的形成及演化。
[Abstract]:The shortage of fresh water resources has become a bottleneck to the economic development of our country. The shallow and salty water in the shallow plain of the North China Plain is rich in water resources, wide in distribution, and has the characteristics of deep buried depth, fast supply, easy exploitation and the like. The salt water resources should also be paid attention to as a non-conventional water source. For the more scientific and reasonable exploitation and utilization of the inland shallow water, the study of its genetic mechanism and its evolution law is particularly important. In this paper, the dynamic characteristics of the saline water in the inland plain are studied from two aspects of the ground water power field and the water chemistry field, and the genetic mechanism of the saline water in the inland plain is analyzed, and the evolution rule is also revealed. In this paper, the typical salt water area in Jiyang County, inland, is an example. Based on the review of the domestic and foreign literature, the field investigation and the method of drilling are used to find out the geological and hydrogeologic conditions of the study area. In the field test such as pumping test and water injection test, On the basis of the combination of the tracer test and the indoor salty fresh water flooding test, the water dynamic effect mechanism of the water formation in the inland shallow water is studied. According to the chemical composition of the shallow water and the distribution of the water chemistry type, the mathematical statistics, the Piper three-line graph and the ion proportion coefficient are used. The temporal and spatial distribution of the water chemistry field in the shallow groundwater in Jiyang is analyzed in a systematic way. On the basis of this, the internal relationship between the formation of the shallow water and the role of various water rocks in the course of the groundwater circulation is discussed, and the hydrogeochemical simulation software, PHREEQC, is used. In this paper, the reverse hydrogeochemical simulation of three typical groundwater flow paths in the study area is carried out, and the simulation results are analyzed and discussed, and the mechanism and the evolution rule of the shallow salt water are revealed. Based on the above-mentioned analysis, the following conclusions are drawn: (1) The shallow salt water in the inland yellow pan-plain area is located in the flow-off zone, the depth of burial and the groundwater dynamic are typical 鈥渕eteorological-evaporation type鈥，

本文編號：2325379