---
title: "Short note: Bore hole log"
subject: "Engineering Geology I"
chapter: 1
key: "semester_3/engineering_geology_i:short-note-bore-hole-log"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/short-note-bore-hole-log
site: BCT Engineering
---

# Short note: Bore hole log

Engineering Geology I · Chapter 1: Geology and Civil Engineering

- Asked in: 2065 Shrawan (old course), 2 marks
- Video: [How To Read Borehole Logs | What You Need to Know To Correctly Interpret Soil Data #education](https://www.youtube.com/watch?v=nNFpItYm3GE) — Soil Mechanics and Engineering Geology
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/short-note-bore-hole-log
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-1

## Question

Write a short note on bore hole log.

## Short answer

A borehole log is a depth-wise written and graphical record of strata encountered during drilling, including descriptions, core recovery, RQD, groundwater level, and in-situ test results. It is used to create geological sections, assess bearing capacity and rock quality, and plan foundation depths and support.

## Answer

A **borehole log** is a written and graphical record of the materials and conditions met while drilling a borehole, drawn depth-wise.

It gives:
- Borehole number, location, elevation, date and method of drilling.
- Depth and thickness of each stratum, with description of soil or rock (type, colour, grain size, weathering).
- Core recovery percentage and **RQD**, and the position of fractures, cavities or weak zones.
- Groundwater level and any water loss during drilling.
- Depths of samples, and results of in-situ tests such as SPT N value.
- A graphic column using standard symbols.

Uses: to prepare geological sections, assess bearing capacity and rock quality, plan foundation depth, tunnel support and grouting, and to keep a permanent record of the ground.

## Check yourself

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

1. A borehole log is:
   A. A map of surface contours
   B. A depth-wise record of materials and conditions met while drilling
   C. A seismic wave record
   D. A list of fossils
   Answer: B. It records strata with depth. (Key point: Definition)

2. Which is recorded in a borehole log?
   A. Rainfall at nearest town
   B. Cost of drilling rig
   C. Core recovery, RQD and groundwater level
   D. Colour of drill rods
   Answer: C. Core recovery, RQD and water are key log data. (Key point: Contents)

3. A borehole log is used to:
   A. Replace topographic maps
   B. Measure earthquake magnitude
   C. Date minerals
   D. Prepare geological sections and assess rock quality
   Answer: D. Logs support sections and design decisions. (Key point: Uses)

## Related in Engineering Geology I

- [Bore hole altitude of fractured bedrock](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Abore-hole-altitude-of-fractured) — Engineering Geology I, chapter 5