--- title: "Preventive measures for landslide and rock slope" subject: "Engineering Geology I" chapter: 6 key: "semester_3/engineering_geology_i:preventive-measures-for-landslide-and" source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/preventive-measures-for-landslide-and site: BCT Engineering --- # Preventive measures for landslide and rock slope Engineering Geology I · Chapter 6: Physical Geology - Asked in: 2066 Bhadra (old course), 3 marks; 2063 Baisakh (old course), 3 marks; 2062 Baisakh (old course), 4 marks; 2059 Chaitra (old course), 2 marks (asked 4 times) - Video: [How to Protect Slope from Rock Falls | Effective and Inexpensive Methods #naturaldisaster](https://www.youtube.com/watch?v=ZD7aTftDZn4) — Soil Mechanics and Engineering Geology - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/preventive-measures-for-landslide-and - Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-6 ## Question Describe the preventive (mitigative) measures for landslides and rock slope instability. ## Short answer Preventive measures include surface and subsurface drainage, slope angle reduction or benching, retaining structures and toe buttresses, rock bolts and anchors, bio-engineering with vegetation, rockfall barriers, slope protection, monitoring and hazard zoning, and river training. ## Answer 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. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What do preventive measures aim to do? A. Increase pore-water pressure B. Reduce driving forces or increase resisting forces C. Steepen the slope D. Remove toe support Answer: B. Slope stability improves by lowering driving or raising resisting forces. (Key point: Principle) 2. Why is drainage called the cheapest and most effective step? A. It adds weight to the head B. It cuts the toe C. It lowers pore-water pressure D. It increases slope angle Answer: C. Reduced pore pressure raises effective stress and shear strength. (Key point: Drainage) 3. Which is a rock reinforcement method? A. Catch drains B. Vetiver planting C. Hazard zoning D. Rock bolts, cable anchors and shotcrete with wire mesh Answer: D. Bolts, anchors, soil nails and dowels reinforce the mass. (Key point: Reinforcement) 4. Which change to slope geometry helps stability? A. Reduce the slope angle, make benches or remove load from the head B. Add load at the head C. Cut the toe steeper D. Increase slope height Answer: A. Unloading the head and flattening the slope cuts driving force. (Key point: Geometry) 5. What does bio-engineering with grass and shrubs provide? A. Deep rock anchoring B. Root binding and reduced surface erosion C. Early warning D. Toe loading Answer: B. Vetiver and bamboo are widely used in Nepal. (Key point: Bio-engineering) ## Related in Engineering Geology I - [Landslide versus slope failure](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Alandslide-versus-slope-failure) — Engineering Geology I, chapter 6 - [All mass movements are landslides](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aall-mass-movements-are-landslides) — Engineering Geology I, chapter 6 - [Landslide causes and slip surface techniques](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Alandslide-causes-and-slip-surface) — Engineering Geology I, chapter 6 ## Related in other subjects - [Preventive measures against corrosion](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acorrosion-preventive-measures) — Concrete Technology and Masonry Structure, chapter 6, asked 3× - [Note for a technical talk on earthquake preventive measures](https://www.bctengineer.com/question.md?key=semester_5%2Fcommunication_english%3Anote-technical-talk-earthquake-preventive) — Communication English, chapter 4 - [Fecal-oral route and preventive measures](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Afecal-oral-preventive) — Water Supply Engineering, chapter 4 - [Soil erosion causes and preventive measures](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aerosion-causes-prevention) — Transportation Engineering I, chapter 4