Effective Stress on Slice Calculator

Effective Normal Stress Formula:

\[ \sigma' = \frac{P}{l} - \Sigma U \]

Total Normal Force:

Length of Arc:

Total Pore Pressure:

Tolerance:

Effective Normal Stress (Pa):

1. What is Effective Stress on a Slice?

Definition: Effective stress is the stress carried by the soil skeleton, calculated as the difference between total stress and pore water pressure.

Purpose: It's crucial in geotechnical engineering for analyzing slope stability, bearing capacity, and settlement calculations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \sigma' = \frac{P}{l} - \Sigma U \]

Where:

\( \sigma' \) — Effective normal stress (Pa)
\( P \) — Total normal force (N)
\( l \) — Length of arc (m)
\( \Sigma U \) — Total pore pressure (N)

Explanation: The total normal force is distributed over the length of the slice, then the pore pressure is subtracted to get the effective stress.

3. Importance of Effective Stress Calculation

Details: Effective stress determines the shear strength of soils and is fundamental to stability analysis in geotechnical engineering.

4. Using the Calculator

Tips: Enter the total normal force in Newtons, length of arc in meters, total pore pressure in Newtons, and tolerance percentage. All values except pore pressure must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical tolerance percentage?
A: A ±5% tolerance is commonly used, but this can vary based on project requirements.

Q2: When would pore pressure be zero?
A: In completely dry conditions or when pore pressure measurements aren't available (conservative estimate).

Q3: How is total normal force determined?
A: It's calculated from the weight of the soil slice and any external loads acting on it.

Q4: What units should I use?
A: The calculator uses SI units (Newtons for force, meters for length, Pascals for stress).

Q5: Why include a tolerance range?
A: To account for measurement uncertainties and material variability in real-world conditions.