Preventive measures for landslide and rock slope

A landslide is the downslope movement of rock, soil or debris. Rock slope instability is failure of rock blocks along discontinuities (plane, wedge, toppling).

Preventive and mitigative measures reduce driving forces or increase resisting forces.

1. Surface and subsurface drainage: catch drains, lined channels, horizontal drains and drainage tunnels lower the pore-water pressure. It is the cheapest and most effective step.
2. Slope geometry change: reduce the slope angle, make benches, or remove load from the head.
3. Toe loading and retaining structures: gabion walls, retaining walls, buttresses, and toe berms.
4. Rock reinforcement: rock bolts, cable anchors, soil nails, shotcrete with wire mesh, and rock dowels.
5. Bio-engineering: grass, shrubs and trees (vetiver, bamboo) give root binding and cut surface erosion. Widely used in Nepal.
6. Rockfall control: catch ditches, rock-fall barriers, and trimming loose blocks.
7. Slope protection: stone or concrete lining, geotextiles, and erosion-control mats.
8. Avoidance, monitoring and planning: hazard zoning, route realignment, and instruments (inclinometer, extensometer, piezometer) with early warning.
9. River training at the toe: spurs and check dams to stop undercutting.