--- title: "Landslide causes and mitigation" subject: "Engineering Geology II" chapter: 5 key: "semester_4/engineering_geology_ii:landslide-causes-mitigation" source: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/landslide-causes-mitigation site: BCT Engineering --- # Landslide causes and mitigation Engineering Geology II · Chapter 5: Geological Hazards - Asked in: 2078 Baisakh, 5 marks; 2078 Poush, 4 marks; 2081 Chaitra, 1+3 marks; 2074 Bhadra, 1 marks; 2068 Bhadra, 4 marks; 2069 Bhadra, 4 marks (asked 6 times) - Video: [Landslides Types, Causes and Preventive Measures for Landslides - Engineering Geology](https://www.youtube.com/watch?v=JwCBrppahJs) — Ekeeda - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/landslide-causes-mitigation - Whole chapter: https://www.bctengineer.com/md/semester_4/engineering_geology_ii/chapter-5 ## Question Describe the causes and the mitigation (preventive/control) measures of landslides. ## Short answer Causes: steep slopes, weak rock, adverse structures, heavy rain, earthquakes, river undercutting, and human activities (road cuts, deforestation). Mitigation: drainage, slope benching, retaining walls, bio-engineering, rock bolting, monitoring, and land-use control. ## Answer A **landslide** is the downslope movement of a mass of rock, debris or earth under gravity. It occurs when the shear stress exceeds the shear strength. #### Causes **1. Natural** - Steep slope and high relief; weak rocks (phyllite, shale, Siwalik mudstone), weathered rock and thick colluvium. - Adverse geological structure: joints, bedding or foliation dipping out of the slope, faults and shear zones. - Heavy rainfall, snow melt, and high groundwater (pore pressure). - Earthquake shaking. - River undercutting and toe erosion. - Weathering and loss of vegetation. **2. Human (anthropogenic)** - Unplanned road cutting and slope excavation. - Blasting, quarrying and mining. - Deforestation and overgrazing. - Irrigation and leakage of water, poor drainage. - Loading by buildings and fills; reservoir fluctuation. #### Mitigation (preventive and control) measures 1. **Avoidance:** hazard mapping and zoning; avoid building on unstable slopes. 2. **Drainage:** surface drains, catch drains, sub-surface drains and horizontal drains to reduce water. 3. **Slope geometry:** reduce slope angle, benching, removal of loose material at the head; add weight at the toe. 4. **Retaining structures:** retaining and breast walls, gabions, crib walls at the toe. 5. **Reinforcement:** rock bolts, anchors, soil nailing, wire mesh, shotcrete. 6. **Bio-engineering:** grass, shrubs and trees to bind the soil. 7. **River training:** spurs and check dams to prevent toe erosion. 8. **Monitoring and early warning:** inclinometers, crack gauges, rain gauges. 9. **Community awareness** and land use control. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. When does a landslide occur? A. When pore pressure is zero B. When shear stress exceeds shear strength C. When shear strength exceeds shear stress D. When the slope is flat and dry Answer: B. Failure happens when driving shear stress exceeds the resisting strength. (Key point: Landslide occurrence) 2. Which is a human cause of landslides? A. River undercutting B. Natural weathering C. Unplanned road cutting and slope excavation D. Earthquake shaking Answer: C. Human causes include cutting, blasting, deforestation, poor drainage and loading. (Key point: Anthropogenic cause) 3. Why are surface and sub-surface drains used for landslide control? A. To add weight to the slope B. To steepen the slope C. To remove retaining walls D. To reduce water and pore pressure in the slope Answer: D. Drains reduce water, thus pore pressure, increasing stability. (Key point: Drainage measure) 4. Which slope geometry change improves stability? A. Reduce slope angle, bench, add weight at the toe B. Add load at the head C. Cut the toe D. Steepen the slope Answer: A. Removing material at the head and adding weight at the toe reduce driving force. (Key point: Slope geometry) ## Related in Engineering Geology II - [Mitigation measures of erosion](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aerosion-mitigation) — Engineering Geology II, chapter 5 - [Problems of Lesser Himalaya with mitigation](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Alesser-himalaya-problems) — Engineering Geology II, chapter 2, asked 5× - [Mitigation of geological problems in Himalaya](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Ahimalaya-problems-mitigation) — Engineering Geology II, chapter 2 - [Mitigation of geological hazards](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Ageohazard-mitigation-measures) — Engineering Geology II, chapter 5 - [Himalayan hazards and mitigation](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Ahimalaya-hazards-mitigation) — Engineering Geology II, chapter 5 - [Why Nepal Himalaya is landslide-prone](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Anepal-landslide-prone) — Engineering Geology II, chapter 5 ## Related in other subjects - [Preventive measures for landslide and rock slope](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Apreventive-measures-for-landslide-and) — Engineering Geology I, chapter 6, asked 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 - [Accident study objectives, causes, preventive measures](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Aaccident-study-objectives-causes-prevention) — Transportation Engineering II, chapter 1 - [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