Shear Strength along Slip Plane Calculator

Shear Strength Formula:

\[ \zeta_{soil} = (C_s \times L) + (W \times \cos(\theta) \times \tan(\phi)) \]

Cohesion of Soil (C_s):

Length of Slip Plane (L):

Weight of Wedge (W):

Slope Angle (θ):

Angle of Internal Friction (φ):

Tolerance:

Shear Strength (ζ_soil):

1. What is Shear Strength along Slip Plane?

Definition: Shear strength along a slip plane is the maximum resistance of soil to shear stresses before failure occurs along a potential sliding surface.

Purpose: This calculation is crucial for slope stability analysis and designing retaining structures to prevent landslides.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \zeta_{soil} = (C_s \times L) + (W \times \cos(\theta) \times \tan(\phi)) \]

Where:

\( \zeta_{soil} \) — Shear strength along slip plane (Pa)
\( C_s \) — Cohesion of soil (Pa)
\( L \) — Length of slip plane (m)
\( W \) — Weight of soil wedge (kg)
\( \theta \) — Slope angle (degrees)
\( \phi \) — Angle of internal friction (degrees)

Explanation: The formula combines the cohesive strength component with the frictional resistance component to determine total shear strength.

3. Importance of Shear Strength Calculation

Details: Accurate shear strength calculation helps prevent slope failures, ensures safe construction on slopes, and aids in designing appropriate stabilization measures.

4. Using the Calculator

Tips: Enter all required parameters including cohesion, slip plane length, wedge weight, slope angle, friction angle, and tolerance percentage (default ±5%).

5. Frequently Asked Questions (FAQ)

Q1: What is cohesion in soil mechanics?
A: Cohesion is the component of shear strength that is independent of normal stress, representing the "stickiness" of soil particles.

Q2: How is angle of internal friction determined?
A: It's typically measured through laboratory tests like direct shear or triaxial tests on soil samples.

Q3: Why include a tolerance percentage?
A: The tolerance accounts for uncertainties in input parameters and provides a safety margin for design purposes.

Q4: What units should be used for input?
A: Use Pascals for cohesion, meters for length, kilograms for weight, and degrees for angles.

Q5: How does slope angle affect shear strength?
A: As slope angle increases, the shear strength typically decreases due to reduced normal forces on the slip plane.