基于多孔非稳定抽水试验的缓倾层状含水层各向异性渗透参数计算

Calculation of anisotropic permeability parameters of flat pitch aquifer based on multiple-well unsteady pumping test

探讨通过多孔抽水试验的降深(s)-时间(t)关系获取水文地质参数中的各向异性参数。利用重庆市渝北区某场地砂岩含水层的多孔非稳定流抽水试验数据,结合非轴向各向异性渗透系数张量的理论,通过运用Matlab编程迭代计算了渗透系数张量的比值及其主要方向。结果显示,2组试验结果所获得的数据较为吻合,渗透系数(K)张量的方向θ值范围为[8°,18°],Ky/Kx的取值范围为[7.5,13]。该结果证明了计算方法的适用性和合理性,运用该方法确定含水层各向异性渗透参数所需的核心参数为s-lnt直线在零降深上的截距。

The parameters of anisotropy of hydrogeology can be obtained through drawdown-time relationship of multiple-well pumping test. In this paper,the multiple-well unsteady pumping test data are used to calculate the main direction and specific value of permeability tensor by Matlab incorporating with non-axial anisotropic permeability tensor theory. The final result which is consistent with the actual drawdown condition is obtained after contrastive analysis from two separate test results,with the main direction range of [8°,18°],and the Ky/Kxrange of [7. 5,13]. The calculation method proves to be feasible and rational for the non-axial anisotropic permeability tensor theory. It points out that the key parameter to calculate anisotropic permeability parameters is the intercept of s-lnt curve.