1. What is Critical Depth for Cohesive Soil?

Definition: The Critical Depth for Factor of Safety is the depth at which the factor of safety against slope failure or other geotechnical hazards reaches a critical value.

Purpose: It helps geotechnical engineers determine the safe excavation depth for cohesive soils to prevent slope failures.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( h_{Critical} \) — Critical Depth for Factor of Safety (meters)
• \( F_c \) — Factor of Safety with respect to Cohesion
• \( H \) — Depth at Mobilized Cohesion (meters)

Explanation: The critical depth is calculated by multiplying the factor of safety by the depth at which cohesion is mobilized.

3. Importance of Critical Depth Calculation

Details: Proper calculation of critical depth ensures safe excavation practices, prevents slope failures, and maintains structural stability in cohesive soils.

4. Using the Calculator

Tips: Enter the Factor of Safety with respect to Cohesion and Depth at Mobilized Cohesion. The ±5% indicates the acceptable tolerance range for these values.

5. Frequently Asked Questions (FAQ)

Q1: What does the ±5% tolerance mean?
A: It indicates the acceptable range of variation in input values that still yield reliable results.

Q2: How is Factor of Safety with respect to Cohesion determined?
A: It's typically determined through laboratory tests on soil samples and analysis of slope stability.

Q3: What affects the Depth at Mobilized Cohesion?
A: Soil type, moisture content, and external loads all influence this depth.

Q4: When would this calculation be most important?
A: During excavation planning, retaining wall design, or any construction involving slopes in cohesive soils.

Q5: How conservative is this calculation?
A: It provides a basic safety factor; additional analysis may be needed for critical projects.

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