有入渗时地下水位变动下的分水岭移动规律

摘要

根据相似原理,在室内建立能模拟地下水分水岭移动特征的模型.模拟一定降雨条件下,保持一侧河渠水位不变,改变另一侧水位,并加入示踪剂,观察不同水位差时地下水运动特征并记录测压管水位,绘制潜水位与分水岭形态,实测分水岭位置,得到试验数据,并对比不同水位差下地下水分水岭的移动特点.同时,根据已知的模型参数,由河间地块潜水流浸润曲线方程与分水岭位置计算式得到理论潜水位和分水岭位置,并与实测值相比.结果表明:通过公式计算得到的理论潜水位和分水岭位置与实际试验测得的数据相吻合,但存在临界值Cr,当两侧水位差△h ＞Cr时不再适用,临界值大小与流体密度、动力黏性系数、渗流断面平均流速、砂样平均粒径等有关.%On the condition of constant infiltration strength,how to acquire the level of groundwater and the watershed position between two parallel ditches are worth studying.Previous scholars issued the theoretical formulas of water table curve and watershed position between two parallel ditches.However,the practice of formulas still need verifying.As a result,we built a model which could imitate the watershed movement indoor according to the similar principle.On the precondition of stable recharge,we kept one side water level constant and changed the other side level.By observing the path of groundwater after adding to tracer,we noted the level of piezometer tube,drew the form of watershed,and compared the watershed characteristic in the different water level.Meanwhile,we obtained a group of academic data by the formulas of water table curve and watershed position and compared with test data.The result showed we could acquire the level of groundwater and the watershed position by formulas.But there is a critical value if water level difference beyond a threshold the formulas will not work.The critical value is related to fluid density,dynamic viscosity coefficient,average flow velocity and average particle size.