试验场地内现场调查发现固结致密砂岩层中存在一个倾角47°的倾斜裂隙含水层。为了研究倾角所产生的影响,通过建立倾斜裂隙微水试验的双重孔隙介质理论模型,利用理论和现场试验数据分析方法,讨论倾角对水文地质参数推估的影响。结果表明:低渗透条件下,倾角越大非振荡水位恢复速度越快;高渗透条件下,倾角越大振荡水位振幅越大。裂隙渗透系数越小,母岩贮水率越大,双重孔隙介质特征参数越大时,倾角上限越小,倾角影响越明显。根据该结论确定出模型适用于倾角大于30°的裂隙含水层。忽略倾角会导致裂隙渗透系数估值偏高,母岩贮水率估值偏低,双重孔隙介质特征参数估值偏低。
In a sloping fractured formation,taking into account the dip angle effects is necessary to accurately estimate hydrogeological parameters. A new double porosity slug test model is developed to examine the influence of the dip angle on the test response by using theoretical and filed data analyses. For the test well,it is found that when the hydraulic conductivity of the aquifer is relatively low,a larger dip angle causes a faster recovery of the non-oscillatory test response; when the aquifer hydraulic conductivity is relatively high,a larger dip angle causes an increase in amplitude of the oscillatory test response. The limiting dip angle increases as the hydraulic conductivity of the fracture zone increases,and as the specific storativity of the matrix decreases,the lumped-parameter decreases. As a result,the application range of the current model is determined; that is,the dip angle effect should be considered in data analyses when the dip angle is larger than 30°. Neglecting the dip angle may result in overestimate of the hydraulic conductivity of the fracture zone,underestimate of the specific storativity of the matrix and underestimate of the lumped-parameter.