---
title: "Slope failure types and prevention"
subject: "Soil Mechanics"
chapter: 11
key: "semester_4/soil_mechanics:slope-failure-types-prevention"
source: https://www.bctengineer.com/q/semester_4/soil_mechanics/slope-failure-types-prevention
site: BCT Engineering
---

# Slope failure types and prevention

Soil Mechanics · Chapter 11: Stability of Slopes

- Asked in: 2076 Baisakh, 2 marks; 2075 Bhadra, 3 marks (asked 2 times)
- Video: [Types of Slope Failure in soil | Elementary Engineering](https://www.youtube.com/watch?v=OBrDbyaHFls) — Elementary Engineering
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/soil_mechanics/slope-failure-types-prevention
- Whole chapter: https://www.bctengineer.com/md/semester_4/soil_mechanics/chapter-11

## Question

Write down the types of slope failures and explain the measures that can be taken to prevent slope failure.

## Short answer

Types include rotational, translational, compound, wedge, infinite slope failures, and falls/flows/creep. Prevention involves flattening slopes, unloading the crest, adding berms or retaining walls, installing drains, reinforcing with nails or geotextiles, vegetation, and soil stabilisation.

## Answer

#### Types of slope failure

1. **Rotational slip** (face, toe and base failures): a curved surface in homogeneous clay.
2. **Translational (planar) slip:** a shallow plane parallel to the slope, in layered soil or cohesionless soil.
3. **Compound slip:** partly curved and partly plane, over a hard layer.
4. **Wedge failure:** sliding on intersecting weak planes.
5. **Infinite slope failure:** shallow slide on a long uniform slope.
6. **Falls, flows and creep:** rapid fall of blocks or flow of saturated soil, and slow downhill movement.

#### Measures to prevent slope failure

*Reduce the driving forces*

- Flatten the slope or reduce its height, or construct benches.
- Remove the load from the top (unload the crest).

*Increase the resisting forces*

- Add a **berm or counterweight** at the toe.
- Construct **retaining walls, gabion walls, or piles** at the toe.
- Use **reinforced earth, geotextiles, soil nails or rock anchors.**
- Replace weak soil by better material, or compact the soil.
- Provide **vegetation and bio-engineering** (grass, shrubs, trees) to bind the soil and reduce erosion.

*Control water*

- Provide **surface drains and catch-water drains** above the slope to divert runoff.
- Provide **sub-surface drains,** horizontal drains or sand blankets to reduce pore pressure.
- Seal cracks and use impermeable surface covering where required.
- Provide filters and weep holes behind retaining structures.

*Others*

- Soil stabilisation by grouting, lime or cement; control vibrations from blasting; and keep monitoring with instruments.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is compound slip?
   A. Sliding of a wedge only
   B. Partly curved and partly plane failure surface, over a hard layer
   C. Shallow slide on infinite slope
   D. Rapid flow of saturated soil
   Answer: B. It combines a circular arc with a planar part. (Key point: Compound slip)

2. Which measure reduces driving forces?
   A. Flatten the slope or unload the crest
   B. Add pore water
   C. Remove the toe berm
   D. Cut the toe steeper
   Answer: A. Lower height or slope angle and crest load reduce shear stress. (Key point: Reduce driving forces)

3. Which measure increases resisting forces?
   A. Removing the toe
   B. Blasting nearby
   C. Surcharging the crest
   D. Toe berm, retaining walls, piles, reinforced earth or soil nails
   Answer: D. These add resisting force or reinforcement. (Key point: Increase resisting)

4. Why provide surface and sub-surface drains?
   A. To add weight
   B. To increase seepage forces
   C. To divert runoff and reduce pore pressure, which keeps effective stress and strength high
   D. To soften the soil
   Answer: C. Lower pore pressure raises strength. (Key point: Water control)

## Related in Soil Mechanics

- [Remedial measures for slope failure](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Aslope-remedial-measures) — Soil Mechanics, chapter 11
- [Causes of slope failure](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Aslope-failure-causes) — Soil Mechanics, chapter 11, asked 4×
- [Types of slope failure](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Aslope-failure-types) — Soil Mechanics, chapter 11, asked 2×

## Related in other subjects

- [Force P to prevent block sliding down incline](https://www.bctengineer.com/question.md?key=semester_1%2Fapplied_mechanics%3Ablock-50kg-force-p-prevent-sliding-down) — Applied Mechanics, chapter 5
- [In-plane, out-of-plane failure and remedial measures](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Ain-plane-out-of-plane-remedial) — Concrete Technology and Masonry Structure, chapter 9
- [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×
- [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