Cohesion of Soil for Circular Footing given Value of Bearing Capacity Factor Calculator

Cohesion Formula:

\[ C = \frac{q_f - \sigma_s}{7.4} \]

Cohesion of Soil (kPa):

Cohesion Range (5% tolerance):

1. What is Cohesion of Soil for Circular Footing?

Definition: This calculator determines the cohesion value of soil beneath a circular footing based on bearing capacity and surcharge pressure.

Purpose: It helps geotechnical engineers and construction professionals assess soil strength for foundation design.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ C = \frac{q_f - \sigma_s}{7.4} \]

Where:

\( C \) — Cohesion of soil (kPa)
\( q_f \) — Ultimate bearing capacity (kPa)
\( \sigma_s \) — Effective surcharge (kPa)
7.4 — Bearing capacity factor for circular footings

Explanation: The difference between bearing capacity and surcharge is divided by the bearing capacity factor to determine soil cohesion.

3. Importance of Soil Cohesion Calculation

Details: Proper cohesion estimation ensures stable foundation design, prevents settlement issues, and maintains structural integrity.

4. Using the Calculator

Tips: Enter the ultimate bearing capacity and effective surcharge in kPa, plus an optional tolerance percentage (default 5%). All values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the bearing capacity factor 7.4?
A: This empirical factor relates soil cohesion to bearing capacity for circular footings under specific conditions.

Q2: When would I adjust the tolerance?
A: Increase tolerance for highly variable soils or when conservative estimates are needed for safety.

Q3: What's a typical cohesion range for soils?
A: Clay soils: 10-200 kPa, silt: 5-50 kPa, sand: 0-10 kPa (non-cohesive).

Q4: How is effective surcharge determined?
A: It's the vertical stress from any additional loads above the foundation level.

Q5: Does this apply to non-circular footings?
A: No, different bearing capacity factors apply for square or strip footings.