Unit Weight of Non Cohesive Soil given Bearing Capacity of Circular Footing Calculator

Unit Weight of Soil Formula:

\[ \gamma = \frac{q_{fc} - (\sigma_s \times N_q)}{0.3 \times N_\gamma \times d_{section}} \]

Ultimate Bearing Capacity (q_fc):

kPa

Effective Surcharge (σ_s):

kPa

Bearing Capacity Factor (N_q):

Bearing Capacity Factor (N_γ):

Diameter of Section:

Unit Weight of Soil (γ):

1. What is Unit Weight of Non Cohesive Soil?

Definition: This calculator determines the unit weight of non-cohesive soil based on the bearing capacity of a circular footing and other soil parameters.

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

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \gamma = \frac{q_{fc} - (\sigma_s \times N_q)}{0.3 \times N_\gamma \times d_{section}} \]

Where:

\( \gamma \) — Unit weight of soil (kN/m³)
\( q_{fc} \) — Ultimate bearing capacity (kPa)
\( \sigma_s \) — Effective surcharge (kPa)
\( N_q \) — Bearing capacity factor dependent on surcharge (±5%)
\( N_\gamma \) — Bearing capacity factor dependent on unit weight (±5%)
\( d_{section} \) — Diameter of circular footing section (m)

3. Importance of Unit Weight Calculation

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

4. Using the Calculator

Tips: Enter all required parameters. The bearing capacity factors typically have ±5% variability. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is non-cohesive soil?
A: Non-cohesive soils (like sand and gravel) have particles that don't stick together, unlike cohesive soils (like clay).

Q2: How do I determine bearing capacity factors?
A: These depend on soil friction angle - use standard geotechnical tables or laboratory tests.

Q3: What's a typical unit weight for sandy soils?
A: Typically ranges from 16-22 kN/m³, but varies with moisture content and compaction.

Q4: Why is the diameter important?
A: Larger footings distribute load over more area, affecting the bearing capacity calculation.

Q5: How accurate is this calculation?
A: It provides an estimate - always verify with field tests for critical projects.