Steady seepage analysis in soil-rock-mixture slope using the numerical manifold method

Abstract

The NMM (numerical manifold method) was widely adopted to deal with many types of engineering problems involving moving boundaries, such as multiple crack propagation in rock masses. With regular triangular mathematical meshes, the NMM is further developed for two typical steady seepage problems, such as the confined seepage analysis and the unconfined seepage analysis. For unconfined seepage analysis, procedures to determine free surface location are introduced, and incorporated into the NMM code. Several classic numerical examples with analytical or reference solutions, and two challenge examples including a soil-rock-mixture (SRM) dam and a SRM slope are adopted to confirm capability and accuracy of the proposed numerical model for steady seepage problems. The results show that the exit gradient and free surface for steady seepage problems can be accurately calculated with the proposed numerical model. In addition, the existence of rock blocks have an impact to the distribution pattern of predicted contours of water head. More importantly, the proposed numerical model is able to calculate locations of free surface in SRM dam and SRM slope, which is very important in stability analysis of SRM dam and slope.