---
title: "Methods for vertical stress increment"
subject: "Soil Mechanics"
chapter: 8
key: "semester_4/soil_mechanics:methods-vertical-stress-increment"
source: https://www.bctengineer.com/q/semester_4/soil_mechanics/methods-vertical-stress-increment
site: BCT Engineering
---

# Methods for vertical stress increment

Soil Mechanics · Chapter 8: Vertical Stresses Below Applied Loads

- Asked in: 2077 Chaitra, 1 marks
- Video: [Newmarks Influence Chart | Vertical Stress distribution | vertical stress in soil | Soil Mechanics](https://www.youtube.com/watch?v=nQu7qiIlds8) — Civil Engineering Exam
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/soil_mechanics/methods-vertical-stress-increment
- Whole chapter: https://www.bctengineer.com/md/semester_4/soil_mechanics/chapter-8

## Question

Name different methods used to determine the increment in vertical stress at any point below the ground surface due to external load applied on the ground surface.

## Short answer

Methods include Boussinesq’s and Westergaard’s equations, Newmark’s influence chart, Fadum’s chart, approximate 2:1 and 60° load spread methods, pressure bulb diagrams, and Osterberg’s chart for embankment loads.

## Answer

Methods used to find the increase in vertical stress below a loaded area:

1. Boussinesq's equation (point load, and its integrals for line, strip, circular and rectangular loads)
2. Westergaard's equation (for stratified soil)
3. Newmark's influence chart (for irregular areas)
4. Fadum's chart / influence factor charts (for rectangular areas)
5. Approximate 2:1 (or 60°) load spread method
6. Pressure bulb (isobar) diagrams, and Osterberg's chart for embankment (trapezoidal) loads.

## Check yourself

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

1. Which method suits irregular loaded areas?
   A. Newmark's influence chart
   B. Fadum's chart
   C. Westergaard point load
   D. 2:1 only
   Answer: A. Newmark's chart handles any shape. (Key point: Irregular areas)

2. Which equation is for stratified soil?
   A. Boussinesq
   B. Westergaard
   C. Newmark
   D. Fadum
   Answer: B. Westergaard assumes rigid layers. (Key point: Stratified soil)

3. Fadum's chart is used for:
   A. Rectangular areas
   B. Point loads
   C. Circular areas
   D. Irregular areas
   Answer: A. Influence factor chart for rectangles. (Key point: Rectangular areas)

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