【摘要】 通过室内砂柱的水平渗流试验,对大沽河下游咸水入侵区含水砂层的水敏感性进行了评价,对海水入侵治理的注淡压咸和抽咸方案过程中含水层的渗透性变化进行了研究,提出了控制和减小方案实施过程中含水砂层渗透性降低的方法和措施。研究结果表明:该含水层具有显著的水敏感性特征,注淡压咸过程导致其渗透性下降幅度超过了两个数量级;注淡和抽咸的流速分别超过21ml/min和42ml/min时,亦能引起含水砂层水敏感性的发生,称为临界流速;淡水驱替咸水过程中存在一个临界离子强度—7638us/cm,驱替水的离子强度不宜小于该值以避免水敏性的发生。更多还原

【Abstract】 With the level lab.pore-fluid flow experiments for the sand column,this paper gave an assessment of the water sensitivity of the sand aquifer in saline-water intrusion area of the Dagu River lower reach,studied the variations of the hydraulic conductivity of the sand aquifer when the fathering schemes of infusing freshwater to press saline-water and pumping saline-water were actualized,and put forward the methods and measures to control and reduce the decrease of the hydraulic conductivity of the sand aquifer.The results indicate that this sand aquifer has obvious water sensitivity character,the infusing freshwater to press saline-water scheme will result in the hydraulic conductivity decreasing above 2 grades,the flow velocity of the infusion freshwater and pumping saline-water will result in the water sensitivity happening when they reach 21ml/min and 42ml/min respectively which is called critical velocity,there is an critical ion intensity-7638us/cm when the freshwater drives the saline-water,and the water sensitivity will happen if the ion intensity of the driving fresh water is beyond this value.更多还原