考虑起始水力坡降时粘性土渗透系数的确定

Determination of cohesive soil's permeability coefficient after thinking of initial hydraulic gradient

基于粘性土的达西定律和水流连续性原则,建立了考虑起始水力坡降时粘性土的渗透系数公式和起始水头计算公式,并通过渗透系数的极差、反算水头和实测水头的最大偏差和均方差来评价所提出的公式和规程公式的误差。实例分析结果表明:考虑起始水力坡降后,采用所提出的公式得到的渗透系数大于采用规程公式得到的渗透系数值;所得到的渗透系数本身的极差、反算水头与实测水头的最大偏差以及均方差均小于规程中不考虑起始水力坡降时得到的相应值;考虑起始水力坡降后的粘性土的渗透系数更能反映粘性土的实际渗透情况。

A permeability coefficient formula after cohsideration of initial hydraulic gradient and the formula of initial water head were put forward based on Darey Law of cohesive soil and the continuity of stream, then en：ors were estimated through range of permeability coefficient, the maximal deviation and square deviation between back - calculated water head and actual water head. The experiment result indicates that the range of permeability coefficient, the maximal deviations and square deviations between back- calculated water head and actual water head calculated from formula in this paper all are less than those calculated from formula in specification. These demonstrate that the permeability coefficient of cohesive soil abstained after consideration of initial hydraulic gradient inflects the practicable seepage more closely.