摘要
在野外调查的基础上,研究不同钠吸附比(SAR)条件下滨海含水层胶体释放规律,采集天津平原区代表性含水层土样,采用室内批实验和土柱实验,研究胶体释放浓度和释放量的动态特征,识别不同含水介质胶体释放的差异性,同时分析胶体颗粒释放过程中含水介质渗透性变异特征.结果表明,在NaCl和CaCl2混合溶液系统中,含水层含水介质胶体颗粒的释放与地下水溶液所含阳离子价态有关,Ca2+含量越高,SAR越小,胶体越不容易释放出来,Ca2+对胶体释放的抑制作用越强烈.土柱实验表明不同吸附比情况下粉砂和中砂胶体释放浓度均很小;当地下水中SAR为0和8时粉土胶体释放很少,当溶液的SAR为∞时胶体有明显的释放,释放浓度随孔隙体积数的增加而增加,在52个孔隙体积数瞬时达到峰值73.76mg/L,然后缓慢减少,最后累积释放量达0.13mg/g.胶体释放过程中,粉土、粉砂和中砂渗透性损失分别为98.2%、86.7%和95.9%;含水介质渗透性的降低主要是由于释放的胶体颗粒在空间上重新分布造成的.
On the basis of field investigation,batch experiments and column experiments have been conducted to elucidate dynamics of colloid release concentration and amount from the coastal aquifer under different sodium adsorption ratios（SAR）.The differences of colloids release in different aqueous mediums are identified,and the permeability changes of aqueous mediums are investigated in the process of colloid release.The results show that the release capacity of colloidal particles from the aqueous mediums decrease with the increasing of sodium adsorption ratio（SAR） in the mixed solution system of NaCl and CaCl2,and Ca2＋ inhibits the release of the colloid.From the column experiment,it is found that a little colloid particles of silty soil are released at the SAR of influent is 0 and 8,and begin to release obviously when the SAR of influent is ∞,and the release amount of colloidal particles from the aqueous mediums increases gradually with the increasing of pore volumes,and reaches the maximum at pore volumes of 52,then the concentration reduces gradually.The total cumulative release amount of colloidal particles from silty soil is 0.13 mg/g.Very little colloid particles of the fine silty and medium sand are released.The permeability loss of silty soil,fine silty and medium sand are 98.2%,86.7% and 95.9% respectively in the process of colloid release.The permeability losses of aqueous mediums are mainly due to the spatial redistribution of released colloidal particles in the media.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2012年第2期263-268,共6页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金项目(Nos.40872156
40602029)
天津市自然科学基金重点项目(No.11JCZDJC24700)
国家水体污染控制与治理科技重大专项(No.2009ZX07212-003)
关键词
胶体释放
钠吸附比
含水层
渗透性
水文地质
污染控制
滨海地区
colloid release
sodium adsorption ratio
aquifer
permeability
hydrogeology
pollution control
coastal regions.
