Cohesion of Soil given Value of Bearing Capacity Factor Calculator

Cohesion of Soil Formula:

\[ C_s = \frac{q_f - \sigma_s}{5.7} \]

Cohesion of Soil (kPa):

Cohesion Range (5% tolerance):

1. What is Cohesion of Soil given Value of Bearing Capacity Factor?

Definition: This calculator determines the cohesion of soil based on ultimate bearing capacity, effective surcharge, and a bearing capacity factor of 5.7.

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

2. How Does the Calculator Work?

The calculator uses the formula:

\[ C_s = \frac{q_f - \sigma_s}{5.7} \]

Where:

\( C_s \) — Cohesion of soil (kPa)
\( q_f \) — Ultimate bearing capacity (kPa)
\( \sigma_s \) — Effective surcharge (kPa)
5.7 — Bearing capacity factor for cohesive soils

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

3. Importance of Soil Cohesion Calculation

Details: Soil cohesion is critical for determining foundation stability, slope stability, and earthwork design.

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 of 5.7?
A: This is a standard value for cohesive soils in Terzaghi's bearing capacity theory.

Q2: When should I adjust the tolerance percentage?
A: Increase tolerance for less precise measurements or when accounting for soil variability.

Q3: What's a typical cohesion value for clay soils?
A: Soft clay: 10-25 kPa, medium clay: 25-50 kPa, stiff clay: 50-100 kPa.

Q4: How is effective surcharge determined?
A: It's the vertical stress at foundation level from overlying soil layers.

Q5: What if my calculation gives negative cohesion?
A: Check your inputs - effective surcharge shouldn't exceed ultimate bearing capacity.