Cohesion of Soil for Steady Seepage along Slope Calculator

Cohesion Formula:

\[ C = h_c \times \left( (\gamma_{sat} \times \tan(i) \times \cos^2(i)) - (y_S \times \tan(\phi) \times \cos^2(i)) \right) \]

Critical Depth (h_c):

Saturated Unit Weight (γ_sat):

N/m³

Angle of Inclination (i):

Submerged Unit Weight (y_S):

kN/m³

Angle of Internal Friction (φ):

Cohesion of Soil (kPa):

1. What is Cohesion of Soil for Steady Seepage along Slope?

Definition: This calculator determines the cohesion required to maintain slope stability under conditions of steady seepage.

Purpose: It helps geotechnical engineers assess slope stability and design appropriate reinforcement when water seepage is present.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ C = h_c \times \left( (\gamma_{sat} \times \tan(i) \times \cos^2(i)) - (y_S \times \tan(\phi) \times \cos^2(i)) \right) \]

Where:

\( C \) — Cohesion of soil (kPa)
\( h_c \) — Critical depth (m)
\( \gamma_{sat} \) — Saturated unit weight of soil (N/m³)
\( i \) — Angle of inclination to horizontal (°)
\( y_S \) — Submerged unit weight (kN/m³)
\( \phi \) — Angle of internal friction (°)

Explanation: The formula calculates the cohesive strength needed to counteract the destabilizing forces from seepage and slope angle.

3. Importance of Cohesion Calculation

Details: Proper cohesion estimation ensures slope stability, prevents landslides, and informs reinforcement design in wet conditions.

4. Using the Calculator

Tips: Enter all required parameters. Typical values are provided as defaults. All values must be > 0. Results have ±5% tolerance.

5. Frequently Asked Questions (FAQ)

Q1: What is critical depth in this context?
A: It's the depth at which seepage forces most significantly impact slope stability.

Q2: How does seepage affect slope stability?
A: Seepage reduces effective stress and increases pore water pressure, decreasing shear strength.

Q3: What's a typical angle of internal friction for soils?
A: It varies from 0° for pure clay to 45° for dense gravel, with most soils between 25°-35°.

Q4: When would I need this calculation?
A: When designing slopes, embankments, or retaining structures in areas with groundwater flow.

Q5: What if my calculated cohesion is negative?
A: Negative values indicate the slope is stable without cohesion under the given conditions.