Unit Cohesion given Mobilized Shear Resistance of Soil Calculator

Unit Cohesion Formula:

\[ c_u = f_s \times c_m \]

Unit Cohesion (Pa):

1. What is Unit Cohesion given Mobilized Shear Resistance?

Definition: This calculator determines the unit cohesion of soil based on the factor of safety and the mobilized shear resistance.

Purpose: It helps geotechnical engineers assess soil stability and design appropriate foundations or retaining structures.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ c_u = f_s \times c_m \]

Where:

\( c_u \) — Unit cohesion (Pascal)
\( f_s \) — Factor of safety (±5%)
\( c_m \) — Mobilized shear resistance of soil (±5%)

Explanation: The factor of safety is multiplied by the mobilized shear resistance to determine the actual unit cohesion of the soil.

3. Importance of Unit Cohesion Calculation

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

4. Using the Calculator

Tips: Enter the factor of safety and mobilized shear resistance values. Both values must be > 0. The ±5% indicates the typical measurement tolerance.

5. Frequently Asked Questions (FAQ)

Q1: What is unit cohesion in soil mechanics?
A: Unit cohesion is the shear strength of soil attributed solely to cohesive forces between soil particles, independent of normal stress.

Q2: Why is there a ±5% tolerance?
A: The 5% accounts for typical measurement variations in field and laboratory tests for soil properties.

Q3: How is mobilized shear resistance determined?
A: It's typically measured through laboratory tests like direct shear tests or triaxial tests on soil samples.

Q4: What's a typical factor of safety for soils?
A: Common values range from 1.5 to 3.0 depending on soil type and project requirements.

Q5: How does unit cohesion affect slope stability?
A: Higher unit cohesion increases a slope's resistance to failure, while lower values indicate greater landslide risk.