Cohesion of Soil given Mobilised Cohesion Corresponding to Local Shear Failure Calculator

Formula:

\[ C_s = \frac{3}{2} \times C_m \]

Cohesion of Soil (Cs):

1. What is Cohesion of Soil given Mobilised Cohesion?

Definition: This calculator determines the cohesion of soil (Cs) based on the mobilised cohesion (Cm) for local shear failure conditions.

Purpose: It helps geotechnical engineers and soil scientists understand the relationship between mobilised cohesion and actual soil cohesion in failure conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ C_s = \frac{3}{2} \times C_m \]

Where:

\( C_s \) — Cohesion of Soil (kPa)
\( C_m \) — Mobilised Cohesion (kPa)

Explanation: The formula shows that the actual cohesion of soil is 1.5 times the mobilised cohesion observed during local shear failure.

3. Importance of Cohesion Calculation

Details: Accurate cohesion values are critical for slope stability analysis, foundation design, and earth retaining structure calculations.

4. Using the Calculator

Tips: Enter the mobilised cohesion value in kPa and the desired tolerance percentage (default 5%). The calculator will provide the cohesion value and tolerance range.

5. Frequently Asked Questions (FAQ)

Q1: What is mobilised cohesion?
A: Mobilised cohesion is the portion of soil cohesion that is actually resisting shear stress at the time of failure.

Q2: Why is the factor 3/2 used?
A: The 3/2 factor accounts for the relationship between mobilised cohesion and actual cohesion in local shear failure conditions.

Q3: What's a typical range for soil cohesion?
A: Cohesion values vary widely: clay (10-200 kPa), silt (5-50 kPa), sandy soils (0-10 kPa).

Q4: When would I adjust the tolerance?
A: Adjust tolerance based on required precision - higher for critical structures, lower for preliminary estimates.

Q5: How is mobilised cohesion measured?
A: Through laboratory tests like triaxial shear tests or field vane shear tests.