Jacob假定下含水层水流方程的线性探讨

On Linearity of Flow Equation of Aquifer under Jacob Assumptions

在Jacob假定下通过含水层形变的本构方程分析表明,渗透系数是水头的单调增函数,而储水率的含水层骨架弹性贡献部分不受含水层形变影响。参数取值量级分析表明,含水层的储水率为常数,所取常数的计算式因岩性和水头下降幅度的不同而有所不同;渗透系数可否作为常数也取决于岩性和水头下降幅度。对水头下降超过10m的松散砂性含水层及粘性储水层,渗透系数随孔隙水头的下降而减小,水流方程呈非线性。对于半成岩或成岩含水层以及水头下降小于10m的粘性储水层和松散砂性含水层,渗透系数为常数,水流方程呈线性。

Under Jacob assumptions,constitutive equation analysis of aquifer deformation shows that hydraulic conductivity can vary with aquifer deformation and can be expressed as a monotone increasing function of hydraulic head. The skeletal elastic contribution of specific storage, however, is not affected by aquifer deformation. Parameter magnitude analysis reveals that specific storage keeps stability under Jacob assumptions and its constant expressions vary with aquifer type and drawdown amplitude. For loose sandy aquifers and shallow water-bearing clay deposits with their drawdown more than 10m, hydraulic conductivity varies with their elastic deformations and it decreases as the drawdown increases, which results in nonlinear water flow equation. For loose sandy aquifers and shallow water-bearing clay deposits with their drawdown less than 10m, or for rock or semi-rock aquifers, hydraulic conductivity can be treated as a constant and the flow equation is linear.