---
title: "When well foundation is suitable"
subject: "Foundation Engineering"
chapter: 9
key: "semester_5/foundation_engineering:well-suitability-advantages"
source: https://www.bctengineer.com/q/semester_5/foundation_engineering/well-suitability-advantages
site: BCT Engineering
---

# When well foundation is suitable

Foundation Engineering · Chapter 9: Well Foundations

- Asked in: 2080 Baisakh, 2 marks; 2074 Chaitra, 2 marks (asked 2 times)
- Video: [Well Foundation | Components and Their Functions | Pile Foundation vs Well Foundation](https://www.youtube.com/watch?v=lNfQZyXjifE) — STRUCTURE-TECH
- Answer checked by Claude Sonnet 5.5 on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/foundation_engineering/well-suitability-advantages
- Whole chapter: https://www.bctengineer.com/md/semester_5/foundation_engineering/chapter-9

## Question

What are the situations/advantages where a well foundation is more suitable than the other types of foundations?

## Short answer

Well foundations are suitable where deep scour requires founding below riverbed, for large vertical/horizontal loads, in soil with boulders or hard layers, variable depth to firm stratum, and in water without sheeting. Advantages: high rigidity and moment resistance, simple equipment, very high load capacity with small settlement, inspectable base, and economical for deep bridge foundations.

## Answer

A **well foundation** is more suitable than other foundations in the following situations.

1. **Deep scour:** in rivers with deep scour, where the founding level must be well below the bed (bridge piers and abutments).
2. **Large vertical and horizontal loads:** the large cross-section gives high bearing capacity and large lateral resistance.
3. **Soil with boulders or hard layers**, where piles cannot be driven easily.
4. **Variable soil depth:** the well can be sunk through soil of varying depth to reach a firm stratum.
5. **Water at the site:** it can be sunk in water without sheeting and open excavation.

#### Advantages
- It has large rigidity and gives a large moment of resistance.
- It is constructed with simple equipment and local labour.
- It has a very high load capacity: the structure is solid, and settlement is small.
- It can be inspected at the base, so the quality of the founding stratum is verified.
- It is economical for deep foundations of bridges and river training works.

## Check yourself

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

1. A well foundation is especially suitable for:
   A. Light single-storey houses
   B. Dry shallow soil
   C. Temporary works
   D. Bridge piers in rivers with deep scour
   Answer: D. It can reach founding levels well below deep scour. (Key point: Deep scour)

2. Compared with piles, wells are better where:
   A. The soil is very soft only
   B. Boulders or hard layers make driving difficult
   C. Loads are tiny
   D. No equipment is available
   Answer: B. Wells can be sunk through boulders where piles cannot be driven. (Key point: Boulders)

3. An advantage of wells is:
   A. Cheap for shallow depths
   B. No need for dredging
   C. Large rigidity and moment resistance, and base inspection
   D. Low load capacity
   Answer: C. Wells are rigid, high capacity, and the founding stratum can be inspected. (Key point: Advantage)

## Related in Foundation Engineering

- [Why foundations; types of foundation](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Awhy-foundations-types) — Foundation Engineering, chapter 1
- [Components of well foundation with sketch](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Awell-components-sketch) — Foundation Engineering, chapter 9, asked 9×
- [Forces acting on well foundation](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Awell-forces) — Foundation Engineering, chapter 9, asked 2×
- [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×
- [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×
- [Classification of pile foundations](https://www.bctengineer.com/question.md?key=semester_5%2Ffoundation_engineering%3Apile-classification-material-load) — Foundation Engineering, chapter 8

## Related in other subjects

- [Situations demanding pile foundation](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apile-situations) — Building Technology, chapter 2, asked 2×
- [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
- [T/F: radial more reliable than network](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Atf-radial-more-reliable-network) — Transmission and Distribution System Design, chapter 5, asked 2×
- [RE: no more than 3 a's](https://www.bctengineer.com/question.md?key=semester_3%2Ftheory_of_computation%3Are-at-most-3-as) — Theory of Computation, chapter 2