钻孔变水头试验确定低渗透性土层水力参数的方法

Methods for Determining Hydraulic Parameters of Low-permeability Soil Layers by Drilling Variable Head Test

低渗透性土层的水力参数对于基础工程建设、地下水资源评价等具有重要意义。该文以新干县某空旷场地为研究对象,进行钻孔变水头试验,对注水试验、竖管试验和双管试验确定低渗透性土层水力参数的方法进行比较,提出在水头下降一定范围内,运用配线法同时求出低渗透性土层的渗透系数和贮水率。计算结果表明,该研究地区的垂向渗透系数和贮水率分别为:K=7.64e-7m/s,μ=1.87e-3m-1,并用竖管试验加以验证,不同计算方法之间的误差仅为0.13%。该方法对于变水头试验条件下确定低渗透性土层的水力参数具有较好的适用性和推广意义。

The hydraulic parameters of low-permeability soil layer have great significance to the construction of foundation engineering and the evaluation of groundwater resources. In this paper, an open field in Xingan County is taken as the research object to carry out the variable head test in drilling. The methods by water injection test, standpipe test and double-tubes test for determining the hydraulic parameters in low-permeability soil layers are compared. It demonstrates that the permeability coefficient and water storage rate of low-permeability soil layers can be obtained by fittingcurve method in a certain range of head drop. The results show that the vertical permeability coefficient and water storage rate are K=7.64 e-7 m/s, μ=1.87 e-3 m-1 in this site. Verified by the standpipe test, the error of different methods is only 0.13%. The methods have better applicability and popularization significance for determining the hydraulic parameters of low-permeability soil layer under the condition of variable head test.