Unit Weight of Soil given Bearing Capacity for Purely Cohesive Soil Calculator

Unit Weight of Soil Formula:

\[ \gamma = \frac{qf - (Cs \times Nc)}{D \times Nq} \]

Ultimate Bearing Capacity:

Cohesion of Soil:

Bearing Capacity Factor (Cohesion):

Depth of Footing:

Bearing Capacity Factor (Surcharge):

Unit Weight of Soil (N/m³):

1. What is Unit Weight of Soil given Bearing Capacity?

Definition: This calculator determines the unit weight of soil based on bearing capacity factors and soil properties for purely cohesive soils.

Purpose: It helps geotechnical engineers and construction professionals analyze soil properties for foundation design.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \gamma = \frac{qf - (Cs \times Nc)}{D \times Nq} \]

Where:

\( \gamma \) — Unit weight of soil (N/m³)
\( qf \) — Ultimate bearing capacity (Pa)
\( Cs \) — Cohesion of soil (Pa)
\( Nc \) — Bearing capacity factor (cohesion)
\( D \) — Depth of footing (m)
\( Nq \) — Bearing capacity factor (surcharge)

Explanation: The formula calculates the unit weight by considering the bearing capacity minus cohesion effects, divided by depth and surcharge factors.

3. Importance of Unit Weight Calculation

Details: Accurate unit weight estimation is crucial for foundation design, slope stability analysis, and earthwork calculations.

4. Using the Calculator

Tips: Enter all required parameters with their ±5% tolerances. Default values are provided for common soil conditions.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical Nc value for cohesive soils?
A: For purely cohesive soils, Nc is typically 5.14 (Prandtl's value) but often rounded to 9 in practical applications.

Q2: Why include ±5% tolerance?
A: Soil properties naturally vary, so calculations should account for this variability in real-world conditions.

Q3: When is this formula most applicable?
A: Primarily for cohesive soils (clays) where cohesion dominates the bearing capacity.

Q4: How does depth affect the calculation?
A: Deeper footings generally have higher bearing capacity due to increased surcharge.

Q5: What if I get a negative result?
A: Check your inputs - negative values suggest impossible combinations of parameters.