Depth of Mobilized Cohesion given Factor of Safety Calculator

Depth at Mobilized Cohesion Formula:

\[ H_{Mobilised} = \frac{c}{S_n \times \gamma \times F_c} \]

Cohesion of Soil:

kPa

Stability Number:

Unit Weight of Soil:

kN/m³

Factor of Safety with respect to Cohesion:

Depth at Mobilized Cohesion (m):

1. What is Depth of Mobilized Cohesion?

Definition: This calculator determines the depth at which cohesion is mobilized in soil, considering stability factors and safety margins.

Purpose: It helps geotechnical engineers assess slope stability and soil behavior under different conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ H_{Mobilised} = \frac{c}{S_n \times \gamma \times F_c} \]

Where:

\( H_{Mobilised} \) — Depth at mobilized cohesion (meters)
\( c \) — Cohesion of soil (kPa)
\( S_n \) — Stability number (dimensionless)
\( \gamma \) — Unit weight of soil (kN/m³)
\( F_c \) — Factor of safety with respect to cohesion

Explanation: The formula calculates the depth where soil cohesion becomes effective for stability, considering safety factors and soil properties.

3. Importance of Depth Calculation

Details: Accurate depth calculation is crucial for designing stable slopes, retaining walls, and foundations, preventing soil failures.

4. Using the Calculator

Tips: Enter soil cohesion, stability number, unit weight, and safety factor. All values must be > 0. The ±5% indicates typical measurement variability.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical stability number range?
A: Stability numbers typically range from 0.05 to 0.3 depending on slope angle and soil conditions.

Q2: Why include ±5% in inputs?
A: This accounts for typical measurement uncertainties in soil testing and field conditions.

Q3: How does unit weight affect the result?
A: Heavier soils (higher unit weight) generally show shallower mobilized cohesion depths.

Q4: What's a reasonable safety factor?
A: Common factors range from 1.5 to 3.0 depending on project requirements and risk tolerance.

Q5: Can this be used for all soil types?
A: Primarily for cohesive soils. Granular soils require different analysis methods.