Three–dimensional continuous–discontinuous pipe network method for simulating fractured and porous seepage

Abstract

Fractured seepage and porous seepage are critical factors affecting the safety of geotechnical structures in tunneling, slope engineering, and underground energy storage projects. On the basis of the pipe network method (PNM), the three–dimensional continuous–discontinuous pipe network method (C–DPNM^3D) with high grid adaptability is developed to address the problem of insufficient simulation efficiency of fractured seepage and porous seepage. C–DPNM^3D uses Darcy’s law and the mass conservation law as the control equations and combines the first and second boundary conditions. The simulation results of this method are compared with those of the typical finite element method (FEM) and discrete element method (DEM), and its feasibility is confirmed. This method is applied to underground water–sealed oil storage in China. The results reveal that compared with those of the FEM and DEM, the error rate of C–DPNM^3D in calculating three–dimensional large–scale porous seepage and fractured seepage is less than 4.34%, and the computational efficiency increases by more than 99.90%. The large–scale three–dimensional fractured seepage and porous seepage is simulated efficiently, and the application effect in the field of underground water–sealed oil storage is good. C–DPNM^3D is a universal, reliable and efficient method for seepage calculation of underground rock mass structures.