---
title: "Engineering significance of fold"
subject: "Engineering Geology I"
chapter: 5
key: "semester_3/engineering_geology_i:engineering-significance-of-fold"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/engineering-significance-of-fold
site: BCT Engineering
---

# Engineering significance of fold

Engineering Geology I · Chapter 5: Structural Geology

- Asked in: 2080 Baisakh, 2 marks
- Video: [Engineering Significant of faults and Folds/Engineering Geology /BE Civil 3rd sem|CTEVT|PU,TU,KU,POU](https://www.youtube.com/watch?v=nvYE83fYkbE) — Akash Magar 
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/engineering-significance-of-fold
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-5

## Question

Describe the engineering significance of fold.

## Short answer

For dams, upstream-dipping beds are stable, downstream-dipping may slide. Tunnel roofs in anticlines are fractured; synclines collect water and have high pressure. Reservoirs: synclines hold water, anticlines leak. Slopes with outward-dipping beds risk landslides. Synclines form artesian basins, anticlines trap oil and gas.

## Answer

- **Foundation and dams**: dip direction of the limbs decides stability; beds dipping upstream are favourable for dams, while beds dipping downstream, with weak layers, may slide.
- **Tunnels**: crest of an anticline is fractured and loosened (tension), while a syncline trough collects water and has high rock pressure; the best tunnel lines cross the fold axis at a high angle.
- **Reservoirs**: a syncline holds water well, but an anticline can leak along the dipping limbs.
- **Slopes**: beds dipping out of the slope produce landslides.
- **Water and oil**: synclines form artesian basins; anticlines are traps for oil and gas.

## Check yourself

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

1. For a dam on a fold, which bed dip is favourable?
   A. Dipping upstream
   B. Dipping downstream with weak layers
   C. Dipping in any direction equally
   D. Horizontal beds only
   Answer: A. Upstream dip is favourable; downstream dip with weak beds may slide. (Key point: Dam foundation)

2. What happens in the crest of an anticline and trough of a syncline for tunnels?
   A. The crest collects water; the trough is loosened
   B. The crest is fractured and loosened; the trough collects water with high rock pressure
   C. Both are equally strong and dry
   D. Both have no rock pressure
   Answer: B. Anticline crest is in tension and fractured; syncline trough holds water and pressure. (Key point: Tunnels in folds)

3. Which fold is a trap for oil and gas?
   A. Syncline
   B. Recumbent fold only
   C. Anticline
   D. None of them
   Answer: C. Anticlines trap oil and gas; synclines form artesian basins. (Key point: Water and oil)

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