---
title: "Dynamic compaction"
subject: "Foundation Engineering"
chapter: 10
key: "semester_5/foundation_engineering:dynamic-compaction"
source: https://www.bctengineer.com/q/semester_5/foundation_engineering/dynamic-compaction
site: BCT Engineering
---

# Dynamic compaction

Foundation Engineering · Chapter 10: Foundation Soil Improvements

- Asked in: 2080 Baisakh, 1 marks
- Video: [Dynamic Compaction for Soil Improvement / Soil Stabilization.](https://www.youtube.com/watch?v=w4fu41bA56Y) — Construction Projects 
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/foundation_engineering/dynamic-compaction
- Whole chapter: https://www.bctengineer.com/md/semester_5/foundation_engineering/chapter-10

## Question

What is dynamic compaction?

## Short answer

Dynamic compaction drops a heavy weight (10–40 t) from heights of 10–40 m in a grid pattern, densifying loose granular and fill soils to significant depth by impact energy.

## Answer

**Dynamic compaction** is a ground improvement method where a heavy weight (10-40 t) is repeatedly dropped from a great height (10-40 m) on the ground surface in a grid pattern. The impact energy densifies loose granular and fill soils to considerable depth.

## Check yourself

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

1. What is dynamic compaction?
   A. Dropping a heavy weight repeatedly onto the ground in a grid to densify it
   B. Vibrating a probe in sand with water jets
   C. Injecting grout
   D. Rolling thin layers
   Answer: A. Impact energy from repeated drops densifies loose granular and fill soils. (Key point: Definition)

2. What are typical weight and drop height?
   A. 100 t from 5 m
   B. 0.5 t from 100 m
   C. 1 t from 1 m
   D. 10-40 t from 10-40 m
   Answer: D. Heavy weights of 10-40 t are dropped from great heights of 10-40 m. (Key point: Weight and drop)

3. Which soils does it suit?
   A. Solid rock
   B. Loose granular and fill soils
   C. Peat only
   D. Soft saturated clay
   Answer: B. The impact densifies loose granular and fill soils to considerable depth. (Key point: Soil types)

## Related in Foundation Engineering

- [Types of mechanical and dynamic compaction](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Amechanical-dynamic-compaction-names) — Foundation Engineering, chapter 10