不同类型岩土浸泡水实验分析

Analysis of Different Types of Rock-soil in Soaking Experiment

为研究降水补给地下水过程中在包气带发生的物质交换及地下水化学演化的特征,在沂源地区采集不同类型的岩土样品11组,按5min和48h的浸泡时间以1∶5的固液比分两组进行了浸泡试验,检测并分析了不同岩土浸泡水中的K+、Na+、Ca2+、Mg2+、Cl-、SO2-4、HCO-3和NO-3等组成及含量变化。结果表明,不同类型岩土样品经浸泡后均有大量物质进入浸泡水中,并随浸泡时间的延长,除个别离子含量减少外,K+、Na+、Cl-、SO2-4等大部分离子均出现不同程度增加。说明在天然降水补给地下水过程中,降水通过对包气带的淋溶作用,使包气带岩土中的大量物质转入水中,水化学性质发生重大变化。由此可认定,地下水的大部分化学组分来源于降水转化为地下水过程中包气带的淋溶作用。

In order to study the characteristics of substance exchange and the chemical evolution of groundwater in the aeration zone during precipitation recharge, 11 groups of different types of rock-soil samples were collected in Yiyuan, Shandong province, and they were divided, according to the solid-liquid ratio of 1∶5, into 2 groups for soaking test with 5 min and 48 h of soaking time respectively.The composition and content characteristics of K＋, Na＋, Ca2＋, Mg2＋, Cl-, SO, HCO, and NO in different types of rock-soil soaking water were detected and analyzed.Results of the soaking experiment show that a large number of substances in the rock-soil samples have entered into the soaking water after they are soaked and that with the increase of the soaking time, the contents of most ions such as K＋, Na＋, Cl- and SO have increased in varying degrees, with only a few exceptions.This means that in the process of precipitation recharge a large number of substances have been leached out from rock-soil in the aeration zone into the groundwater whose chemical properties has changed greatly.Thus it can be concluded that most chemical constituents of groundwater come from the leaching process of the aeration zone during precipitation recharge to groundwater.