Question

The correct vertical stress profile in the case of tributary area method for pillar design is

• A. I
• B. II
• C. III
• D. IV

Hint:

The tributary area method assumes that each pillar carries the weight of the overburden directly above it, leading to a uniform vertical stress distribution across the pillar width.

Answer 1

The Correct Option is C

In the tributary area method for pillar design, the vertical stress distribution on the pillar is assumed to be:
- Uniform over the entire pillar width,
- With abrupt stress transfer at the edges of the pillar.
This represents a simplified engineering approach where the pillar is assumed to support the full overburden load acting over its tributary width.
Among the given stress profiles in the figure:
- Profile I corresponds to highly peaked stress concentration (not assumed in tributary method).
- Profile II shows non-uniform distribution with edge effects.
- Profile III shows nearly flat (uniform) stress distribution across the width of the pillar — this matches the tributary area assumption.
- Profile IV represents an unrealistic inverted distribution.
Thus, Profile III is correct.
Final Answer: III