Landslides can pose a threat to the integrity of new and existing pipelines if they are not mitigated. Improving subsurface drainage of groundwater is one of the most widely used stabilization strategies for mitigating landslides affecting pipelines because subsurface drainage requires minimal design and costs and can improve the overall stability. The appropriate design and implementation of this approach could lower the groundwater table within the landslide as a primary factor triggering landslide movement by reducing the driving force and increasing the shear strength or resisting force within the landslide mass. Thus, the subsurface drains are conventionally employed in the mitigation of most landslides that may threaten pipelines either as a single strategy or in conjunction with other measures.
This paper presents how effective subsurface drainage systems are for improving slope stabilization in various site conditions. Included in the discussion is the predesign investigation considerations. The results of a series of two-dimensional limit equilibrium and seepage analyses are presented to evaluate the effectiveness of subsurface drainage systems. Site conditions explored in this paper include the location of the right-of-way compared to the boundary of landslide, geometry of landslide, and groundwater level. A model that uses genetic expression programming as a computational intelligence technique is introduced that predicts the effectiveness of subsurface drainage systems.