Submerged Unit Weight given Factor of Safety for Cohesive Soil Calculator

Formula Used:

\[ \gamma' = \frac{C_s}{(F_s - (\frac{\tan(\phi)}{\tan(i)})) \times z \times \cos(i) \times \sin(i)} \]

Cohesion of Soil (C_s):

kPa

Factor of Safety (F_s):

Angle of Internal Friction (φ):

Angle of Inclination (i):

Depth of Prism (z):

Submerged Unit Weight (γ'): kN/m³

1. What is Submerged Unit Weight given Factor of Safety for Cohesive Soil?

Definition: This calculator determines the submerged unit weight of cohesive soil considering the factor of safety against slope failure.

Purpose: It helps geotechnical engineers assess the stability of submerged soil slopes and foundations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \gamma' = \frac{C_s}{(F_s - (\frac{\tan(\phi)}{\tan(i)})) \times z \times \cos(i) \times \sin(i)} \]

Where:

\( \gamma' \) — Submerged unit weight (kN/m³)
\( C_s \) — Cohesion of soil (kPa)
\( F_s \) — Factor of safety (typically 2.8 ±5%)
\( \phi \) — Angle of internal friction (°)
\( i \) — Angle of inclination to horizontal (°)
\( z \) — Depth of prism (m)

Explanation: The formula calculates the submerged unit weight required to maintain stability given the other parameters.

3. Importance of Submerged Unit Weight Calculation

Details: Proper calculation ensures safe design of submerged structures, retaining walls, and slopes in cohesive soils.

4. Using the Calculator

Tips: Enter all required parameters. Angles should be in degrees. The factor of safety typically ranges from 1.5-3.0 with ±5% tolerance.

5. Frequently Asked Questions (FAQ)

Q1: What is typical cohesion value for cohesive soils?
A: Clay soils typically have cohesion values from 5-50 kPa, depending on soil type and moisture content.

Q2: Why is factor of safety important?
A: It accounts for uncertainties in soil properties and loading conditions, typically ranging from 1.5-3.0 for slopes.

Q3: How does angle of inclination affect the result?
A: Steeper angles generally require higher submerged unit weights for stability.

Q4: What is submerged unit weight?
A: It's the effective unit weight of soil when submerged, accounting for buoyancy effects.

Q5: When would I use this calculation?
A: For designing underwater foundations, retaining structures, or analyzing slope stability in cohesive soils.