岩石裂隙非饱和水力模型及其模拟计算

A model for unsaturated seepage flows in rock fracture and its calculation

基于单裂隙非饱和渗流入侵概念模型,考虑裂隙排水起始毛细压力及排水过程开度范围等因素,推导了单裂隙非饱和渗透的饱和度与毛细压力及相对渗透系数的本构关系,根据有关试验资料进行了模型的验证分析。研究表明:推导的单裂隙饱和度与毛细压力关系与试验结果吻合较好,饱和度与相对渗透系数关系与经典模型具有良好可比性。考虑裂隙空隙存在非连通情况及起始毛细压力机制,引入压力修正项,同时考虑最小及最大排水概率开度能使入侵概念模型更符合实际。最后采用离散元软件UDEC应用本模型进行了单裂隙非饱和排水过程模拟,计算结果与Van Genchten模型结果接近反映模型合理。

Based on the invading conceptual model for unsaturated seepage of a single fracture,and considering fracture initial capillary pressure of drainage,fracture aperture range of drainage process,etc.,a constitutive model for unsaturated seepage saturation,capillary pressure and relative permeability coefficient of a single fracture is derived,and the verification analysis of the model is done according to the experimental data.The study shows that the derived model for saturation and capillary pressure about a single fracture is in good agreement with the experimental results,and the relationship between saturation and relative permeability coefficient has good comparability with that of the classical model.Taking the disconnection condition of fracture,initial capillary pressure and the minimum and maximum aperture of drainage probability into consideration,the invading conceptual model will be in more accordance with the actual condition when pressure modified term is introduced.Finally,the unsaturated drainage process of a single fracture is simulated by use of software UDEC.The results are close to those of Van Genchten model,and the conclusion that the model is reasonable and reliable is drawn.