坝基岩体裂隙渗流效应数值模拟方法

为获取工程尺度的裂隙岩体三维渗流效应,在裂隙岩体基质岩块和裂隙水力传导特性研究基础上,推导了含裂隙单元渗透系数表达式。基于嵌入裂隙单元(EFE)模型,使用离散裂隙网络(DFNs)技术与连续介质渗流分析方法,提出了利用连续介质渗流分析方法模拟非连续介质渗流效应的数值模拟技术,通过算例对该方法的有效性进行了验证,分析了单元尺度大小对该方法计算准确性的影响,并提出了提高计算精度的措施。工程实例研究表明裂隙岩体渗流分析的EFE模型能够真实地模拟坝基岩体渗流路径和孔隙压力分布,更好地揭示坝基的扬压力实际非规则分布形态。

Numerical analysis method of fluid flow in fractured rock mass of dam foundation

To predict seepage effect of fractured rock in 3 dimension space at engineering scale, based on hydraulic conductivity of rock matrix and fracture,expressions of permeability coefficient for embedded fractured element(EFE) was derived. Base on the model of embedded fracture element, a numerical simulation technique on behalf of discontinuously analytical method was proposed by combination of discrete fracture networks with continuum approach of seepage analysis. Examples were employed to validate the proposed method. The size effects of element were also studied on calculation accuracy and measurements for improvement of the calculation accuracy were then suggested. The case study shows that the EFE model for seepage analysis of fractured rock mass can properly simulate the seepage path and pore pressure distribution of dam foundation rock mass, and reveal the irregular distribution pattern of uplift pressure of dam foundation.