---
title: "Geotechnical problems and their solutions"
subject: "Soil Mechanics"
chapter: 1
key: "semester_4/soil_mechanics:geotechnical-problems-solutions"
source: https://www.bctengineer.com/q/semester_4/soil_mechanics/geotechnical-problems-solutions
site: BCT Engineering
---

# Geotechnical problems and their solutions

Soil Mechanics · Chapter 1: Introduction

- Asked in: 2075 Bhadra, 1+1 marks; 2073 Magh, 2+1 marks (asked 2 times)
- Video: [Understanding why soils fail](https://www.youtube.com/watch?v=5iROUI49Cjw) — The Engineering Hub
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/soil_mechanics/geotechnical-problems-solutions
- Whole chapter: https://www.bctengineer.com/md/semester_4/soil_mechanics/chapter-1

## Question

What are the different geotechnical (soil engineering) problems in civil engineering and infrastructure development? What would be a solution of such problems?

## Short answer

Common geotechnical problems include bearing capacity failure, excessive settlement, slope instability, liquefaction, seepage, swelling soils, and erosion. Solutions involve appropriate foundation design, ground improvement like compaction and stabilization, drainage, retaining structures, and proper site investigation.

## Answer

**Geotechnical problems** are failures or difficulties arising from the poor behaviour of soil, rock or groundwater under or around civil works. Common problems and their usual solutions are listed below.

| Problem | Cause | Solution |
|---|---|---|
| Excessive settlement | Compressible clay, loose fill, peat | Preloading with vertical drains, pile or raft foundation, soil replacement, compaction |
| Bearing capacity failure | Weak soil, high load | Wider or deeper footing, pile/raft foundation, soil stabilisation, grouting |
| Landslide / slope failure | Steep slope, rain, loss of toe support | Flatter slope, benching, retaining wall, drainage, bio-engineering, soil nailing |
| Liquefaction in earthquakes | Loose saturated sand | Densification (vibro-compaction), drainage, pile foundations |
| Seepage and piping | Water flow below dams and weirs | Cut-off walls, sheet piles, impervious blanket, filters, relief wells |
| Swelling and shrinkage | Expansive (black cotton) clays | Replace soil, lime stabilisation, moisture control, deep foundations |
| Earth pressure on walls | Backfill pressure, surcharge | Proper wall design, drainage behind the wall, light backfill |
| Erosion and scour | Flowing water, wind | Riprap, geotextile, vegetation, check dams |
| Collapse of excavations | Unsupported cut | Shoring, sheet piling, dewatering |
| Poor subgrade for roads | Weak or wet soil | Compaction, stabilisation with lime or cement, geosynthetics, drainage |

A proper **site investigation** (boring, sampling, laboratory and field tests) must come first so the correct solution is selected.

## Check yourself

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

1. Excessive settlement on compressible clay is usually solved by:
   A. Cut-off walls and relief wells
   B. Lime stabilisation only
   C. Preloading with vertical drains, pile or raft foundation, or soil replacement
   D. Riprap and vegetation
   Answer: C. Settlement from compressible soils is handled by preloading with drains, deep or raft foundations, replacement or compaction. (Key point: Settlement solution)

2. Which set of measures controls seepage and piping below dams and weirs?
   A. Cut-off walls, sheet piles, impervious blanket, filters, relief wells
   B. Benching and soil nailing
   C. Vibro-compaction
   D. Lime treatment
   Answer: A. Seepage control uses cut-offs, sheet piles, blankets, filters and relief wells. (Key point: Seepage and piping)

3. Liquefaction in earthquakes occurs in and is reduced by:
   A. Dense gravel; by adding load
   B. Expansive clay; by lime
   C. Loose saturated sand; by densification, drainage or pile foundations
   D. Rock; by shoring
   Answer: C. Loose saturated sand loses strength in earthquakes; vibro-compaction, drainage and piles help. (Key point: Liquefaction)

4. For swelling and shrinkage of black cotton clay, which solution is listed?
   A. Replace soil, lime stabilisation, moisture control, deep foundations
   B. Cut-off walls
   C. Check dams
   D. Shoring
   Answer: A. Expansive clays are treated by replacement, lime, moisture control or deep foundations. (Key point: Expansive clay)

5. What must come first so the correct geotechnical solution is chosen?
   A. Construction of the foundation
   B. Ordering of materials
   C. Site investigation (boring, sampling, lab and field tests)
   D. Backfilling
   Answer: C. Proper site investigation is needed before selecting the solution. (Key point: Site investigation first)

## Related in Soil Mechanics

- [Define soil; soil engineering problems](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Adefine-soil-engineering-problems) — Soil Mechanics, chapter 1
- [Historical development of soil mechanics](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Ahistorical-development-soil-mechanics) — Soil Mechanics, chapter 1
- [What is soil mechanics; why study](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Asoil-mechanics-why-study) — Soil Mechanics, chapter 1
- [Boussinesq vs Westergaard solutions](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Aboussinesq-westergaard-difference) — Soil Mechanics, chapter 8
- [Importance of soil mechanics](https://www.bctengineer.com/question.md?key=semester_4%2Fsoil_mechanics%3Aimportance-soil-mechanics) — Soil Mechanics, chapter 1, asked 3×

## Related in other subjects

- [LEP approach in infrastructure development](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Alep-infrastructure-development) — Technology, Environment and Society, chapter 2
- [Key features of infrastructure development policies](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Ainfrastructure-development-policies) — Technology, Environment and Society, chapter 2
- [Solid solutions and solid-solution strengthening](https://www.bctengineer.com/question.md?key=semester_3%2Fmaterial_science%3Asolid-solution-strengthening) — Material Science, chapter 5
- [Scope and importance of geology in civil engineering](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Ascope-and-importance-of-geology) — Engineering Geology I, chapter 1, asked 24×