---
title: "Why tunnel documentation is done"
subject: "Engineering Geology II"
chapter: 4
key: "semester_4/engineering_geology_ii:why-tunnel-documentation"
source: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/why-tunnel-documentation
site: BCT Engineering
---

# Why tunnel documentation is done

Engineering Geology II · Chapter 4: Engineering geology in site selection, investigation & construction/excavation

- Asked in: 2077 Chaitra, 1 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/why-tunnel-documentation
- Whole chapter: https://www.bctengineer.com/md/semester_4/engineering_geology_ii/chapter-4

## Question

Why should documentation in tunnelling be carried out?

## Short answer

Tunnel documentation compares actual ground with predictions to verify design and adjust support, warns of unstable zones and water inflow, provides a legal record for payment and claims, and creates a permanent record for maintenance and future projects.

## Answer

Documentation (geological mapping and recording) is done in tunnelling in order to:
- Compare the actual ground with the predicted geology and verify or revise the design.
- Select and adjust support according to the real rock class.
- Warn of unstable zones, water inflow, gas and squeezing.
- Provide a legal record for payment, claims and disputes.
- Keep a permanent record for maintenance, repairs and later projects.

## Check yourself

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

1. Why is geological documentation carried out in tunnelling?
   A. To compare actual ground with predicted geology and revise the design
   B. To increase overbreak
   C. To avoid support installation
   D. Only to decorate the tunnel lining
   Answer: A. Records of the actual ground verify or revise the design. (Key point: Compare predicted and actual)

2. How does documentation help support design?
   A. It only records the cost
   B. Support is selected and adjusted to the real rock class
   C. Support is fixed before excavation and never changed
   D. It removes the need for support
   Answer: B. Mapping the real rock class lets support be adjusted to actual conditions. (Key point: Support selection)

3. Which is another purpose of the documentation?
   A. Reducing the tunnel length
   B. Predicting the market price of rock
   C. Legal record for payment, claims and disputes
   D. Replacing the geological survey
   Answer: C. Documentation is used as a legal record and permanent record for maintenance and later projects. (Key point: Legal record)

## Related in Engineering Geology II

- [Geological documentation in tunnelling](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Atunnel-geological-documentation) — Engineering Geology II, chapter 4, asked 6×
- [Geology in tunnel site selection](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Atunnel-site-selection) — Engineering Geology II, chapter 4, asked 4×

## Related in other subjects

- [Fault classification, evidences, documentation](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Afault-classification-evidences-documentation) — Engineering Geology I, chapter 5
- [Tunnelling and rock drilling equipment](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Atunnel-rock-drilling-equipment) — Construction Management, chapter 4, asked 3×
- [Tunnelling methods and supports](https://www.bctengineer.com/question.md?key=semester_7%2Fhydropower_engineering%3Atunnelling-methods-supports-realized) — Hydropower Engineering, chapter 6
- [Conventional tunnelling steps and TBM advantage](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Atunnelling-conventional-tbm) — Construction Management, chapter 4