An isobar is a curve which
- AJoins points of equal horizontal stress
- BJoins points of equal vertical stressCorrect
- CJoins points of zero vertical stress
- DJoins the points of maximum vertical stress
Solution
Concept
Definition and characteristics of stress isobar
Formula
NONE
Step-by-step solution
1. An isobar in soil mechanics represents stress distribution below a loaded area. 2. It is a curved surface or line connecting all points below the ground surface that experience equal stress. 3. Specifically, in soil stress analysis, an isobar joins points of equal vertical stress. Answer: B
Explanation
In soil mechanics, an isobar is a stress contour line connecting points below the ground surface that experience equal vertical stress. It is commonly visualized as a pressure bulb to illustrate how applied surface loads distribute stresses throughout the underlying soil mass. Consequently, any point along a given isobar shares the same magnitude of vertical stress.
Why the other options are wrong
A) Isobars connect points of equal vertical stress rather than horizontal stress. C) Isobars connect points of equal non-zero vertical stress intensity. D) Isobars represent contours of uniform stress rather than points of maximum stress.
Shortcut
Isobar = curve joining points of equal vertical stress (equal pressure bulb).
Common mistake
Confusing equal vertical stress contours with equal horizontal stress or maximum stress contours.
Correct answer: B) Joins points of equal vertical stress