摘要
选取鲁北平原区浅层粉土、浅层咸水和大气降水为供试材料,进行室内雨水-咸水驱替试验,研究驱替过程中的含水介质渗透性变化特征,探讨内陆浅层咸水区水动力、水文地球化学过程对水文地质参数变异影响。试验结果表明:雨水驱替咸水饱和土柱过程中,盐分突变,渗透系数由开始的6.49×10-4 cm/s最终降至2.28×10-4 cm/s,并维持相对稳定;第188d后,咸水再次驱替土柱,且完全穿透土柱后,含水介质孔隙度由开始的43.02%大约降至39.73%;在雨水驱替过程中,水温变化对渗透系数波动性变化的影响较为显著。研究认为,内陆咸水区含水介质黏土矿物含量高,黏粒大量膨胀和释放、扩散及Ca/Mg-Na的离子交换作用引起孔隙度降低是造成含水介质的渗透性下降的主因,咸雨水驱替过程中渗透性的变化具有不可逆性。含水介质水文地质参数的变异对于内陆浅层咸水形成和演化有重要影响。
Shallow silt ,shallow salt water and atmospheric precipitation are selected as materials collected from the North Shandong Plains .The variation characteristics of permeability of aquifer medium are studied by rain-saltwater displacement experiment in labo‐ratory ,further ,mechanisms are explored how hydrodynamic and hydrogeochemical processes affect the variation of hydrogeological parameters in inland shallow saltwater region .The experimental results show that ：in the first stage using rainwater to displace the salt water in saturated soil column ,salinity has dramatically changed ,and the permeability has finally dropped 2 .28 × 10^-4 cm/s from the initial value 6 .49 × 10^-4 cm/s then maintaining a relatively stable value;after 188 days ,in the second stage using salt water as supply and adequately penetrating the soil column ,aquifer medium porosity by the start 43 .02% fell to 39 .73% ;during the process of rainwater displacement ,temperature changes have a significant effect on the fluctuating changes of the permeability coeffi‐cient .Studies suggest that aquifer medium clay mineral content is high in inland salt water zones .Porosity decreases by the massive clay expansion with release and diffusion ,Ca/Mg-Na ion exchange action .The reduction of porosity is the main reason which causes permeability of aquifer medium to decrease .Moreover ,the change of permeability has irreversibility in the process of salt-rainwater displacement .In all ,variation of hydrogeological parameters of aquifer medium has an important effect on formation and evolution of shallow salt water in inland .
出处
《中国农村水利水电》
北大核心
2015年第6期61-65,共5页
China Rural Water and Hydropower
基金
国家自然科学基金项目(41172222
41472216)
关键词
浅层咸水
渗透系数
驱替试验
水文地球化学作用
内陆地区
shallow salt water
permeability coefficient
displacement experiment
hydrogeochemical action
inland area
