| 咸淡水驱替过程中的水文地球化学作用 |
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| 引用本文： | 任加国,武倩倩.咸淡水驱替过程中的水文地球化学作用[J].海洋地质与第四纪地质,2008,28(5). |
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| 作者姓名： | 任加国 武倩倩 |
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| 作者单位： | 山东科技大学,地质科学与工程学院,青岛,266510 |
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| 基金项目： | 国家自然科学基金
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| 摘 要： | 在现场水文地质调查的基础上,分别采集大沽河下游地下淡水、海水和含水介质样品,并测定它们的性质和组成,然后用渗流装置模拟海水驱替淡水的过程,测定驱替过程中含水介质渗透性(渗透系数、孔隙度、弥散系数等)和主要离子(Na 、K 、Ca2 、Mg2 )的变化规律,最后,采用数值模拟方法定量研究驱替过程中的水文地球化学作用。研究结果表明,驱替过程中发生了多组分的离子交换作用,Ca2 和Mg2 最大值高于海水和淡水中的离子浓度值,Na —Ca2 、Na —Mg2 发生离子交换;Mg2 达到最大值后有一个降低的"台阶"阶段,此时Mg2 —Ca2 发生离子交换;K 在驱替过程中主要表现为化学吸附。离子交换过程中伴随着矿物溶解-沉淀,海水比例40%后,方解石处于过饱和状态;在驱替过程开始阶段,石膏饱和指数逐渐升高,达到峰值后又开始下降,最后饱和指数又有所升高,但始终处于非饱和状态。
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| 关 键 词： | 咸淡水驱替 离子交换 溶解沉淀 |
HYDROGEOCHEMISTRY IN THE PROCESS OF SALT WATER-FRESHWATER DISPLACEMENT |
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| REN Jia-guo,WU Qian-qian.HYDROGEOCHEMISTRY IN THE PROCESS OF SALT WATER-FRESHWATER DISPLACEMENT[J].Marine Geology & Quaternary Geology,2008,28(5). |
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| Authors: | REN Jia-guo WU Qian-qian |
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| Abstract: | On the basis of hydrogeologic investigation,groundwater,sea water and the medium are collected,whose composition and nature are determined,and then the regularity of permeability(penetration coefficient,porosity and dispersion coefficient) and the main ion(Na ,K ,Ca2 ,Mg2 ) are determined in the course of salt water-freshwater displacement with transfusion installment.Finally,hydrogeochemistry is studied for the displacement with the numerical simulation.The result indicated that ion exchanges take place in the process of salt water-freshwater displacement,the density of Ca2 and Mg2 exceeds that of seawater,and Na -Ca2 and Na -Mg2 appear.There is a smooth step for Mg2 when it reaches maximum value,Na -Mg2 takes place at that time,and K is mainly showed as chemical absorption.Mineral dissolution and precipitation occur with ion exchanges.Calcite reaches saturation when the percent of seawater comes up to 40%.The saturation of gypsum first becomes higher,and then drops when it reaches peak value,and finally rises slowly,but gypsum is in non-saturation state from beginning to the end. |
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| Keywords: | salt water-freshwater displacement ion exchange dissolution and precipitation |
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