---
title: "Shallow versus deep foundation"
subject: "Foundation Engineering"
chapter: 1
key: "semester_5/foundation_engineering:shallow-vs-deep-foundation"
source: https://www.bctengineer.com/q/semester_5/foundation_engineering/shallow-vs-deep-foundation
site: BCT Engineering
---

# Shallow versus deep foundation

Foundation Engineering · Chapter 1: Introduction

- Asked in: 2082 Bhadra, 2 marks
- Video: [Building Foundation Systems l Shallow vs Deep Foundation](https://www.youtube.com/watch?v=sArDBGYuApE) — Lega Design Studio
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/foundation_engineering/shallow-vs-deep-foundation
- Whole chapter: https://www.bctengineer.com/md/semester_5/foundation_engineering/chapter-1

## Question

Differentiate between shallow foundation and deep foundation. Also, name their types.

## Short answer

Shallow foundations (Df ≤ B) transfer load near surface, for good shallow soil, simple construction, low cost. Deep foundations (Df > B, typically Df/B > 4) reach a deep strong stratum, handle heavy or uplift loads, cost more, require special equipment. Types: shallow - isolated, strip, combined, raft; deep - piles, piers, wells.

## Answer

A **shallow foundation** transfers load to the soil near the surface ($D_f \le B$); a **deep foundation** transfers load to a deeper, stronger stratum ($D_f > B$, usually $D_f/B > 4$ to 5 for piles).

| Point | Shallow foundation | Deep foundation |
|---|---|---|
| Depth / width ratio | $D_f/B \le 1$ (up to 3-4 in some books) | $D_f/B > 4$ to 5 |
| Load transfer | Mainly by base bearing | By end bearing and/or skin friction |
| Suitable soil | Good soil near surface | Weak upper soil, strong deep layer |
| Construction | Open excavation, simple | Needs special equipment and skill |
| Cost and time | Low, quick | High, slow |
| Load capacity | Light to moderate | Heavy, also uplift and lateral |
| Analysis | Bearing capacity + settlement | Pile capacity, group effect, negative skin friction |

#### Types
- **Shallow:** isolated (spread) footing, wall (strip) footing, combined footing, strap footing, raft (mat) foundation.
- **Deep:** pile foundation (driven, bored, friction, end-bearing), pier foundation, well (caisson) foundation, drilled shaft.

## Check yourself

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

1. The depth/width ratio usually used for deep foundations (piles) is
   A. less than 1
   B. exactly 1
   C. less than 0.5
   D. greater than about 4 to 5
   Answer: D. Shallow Df/B <= 1; deep foundations Df/B > 4-5. (Key point: Depth ratio)

2. Deep foundations transfer load mainly by
   A. base bearing only
   B. end bearing and/or skin friction
   C. gravity of the soil above
   D. surface adhesion of the superstructure
   Answer: B. Piles carry load through tip resistance and shaft friction, unlike shallow base bearing. (Key point: Load transfer)

3. Which list contains only deep foundations?
   A. Isolated footing, strip footing, raft
   B. Combined footing, strap footing, pile
   C. Pile, pier, well (caisson), drilled shaft
   D. Raft, well, strip footing
   Answer: C. Isolated, strip, combined, strap and raft are shallow types. (Key point: Types)

## Related in Foundation Engineering

- [Classify shallow and deep foundations](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Aclassify-foundations-soil) — Foundation Engineering, chapter 1, asked 4×
- [When piles are preferred to shallow foundations](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-vs-shallow-conditions) — Foundation Engineering, chapter 8, asked 3×

## Related in other subjects

- [Deep foundation types and use of shallow foundations](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adeep-shallow-types-079a) — Building Technology, chapter 2
- [Shallow and deep wells](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Ashallow-deep-wells) — Water Supply Engineering, chapter 2, asked 4×
- [Types of shallow foundation](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Ashallow-foundation-types) — Building Technology, chapter 2
- [Foundation requirements and shallow foundation types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Afoundation-define-requirements-shallow) — Building Technology, chapter 2