Factor of Safety given Submerged Unit Weight Calculator

Factor of Safety Formula:

\[ F_s = \frac{\gamma' \cdot \tan(\phi)}{(\gamma_{sat} \cdot \tan(i)} \]

Submerged Unit Weight (γ'):

kN/m³

Angle of Internal Friction (φ):

Saturated Unit Weight (γ_sat):

kN/m³

Angle of Inclination (i):

Safety Margin:

Factor of Safety (F_s):

Definition: The Factor of Safety (F_s) expresses how much stronger a system is than it needs to be for an intended load.

Purpose: It helps geotechnical engineers assess the stability of slopes and foundations by comparing resisting forces to driving forces.

The calculator uses the formula:

\[ F_s = \frac{\gamma' \cdot \tan(\phi)}{(\gamma_{sat} \cdot \tan(i)} \]

Where:

Explanation: The formula compares the resisting forces (numerator) to the driving forces (denominator) in a slope stability analysis.

Details: Proper calculation ensures slope stability, prevents failures, and provides economic design while maintaining safety margins.

Tips: Enter all required parameters. The safety margin (default 5%) can be adjusted to provide additional conservatism in the calculation.

Q1: What is a typical acceptable Factor of Safety?
A: For slopes, typically 1.3-1.5 is acceptable. For foundations, 2.0-3.0 is common.

Q2: Why use submerged unit weight?
A: Submerged weight accounts for buoyancy effects when soil is below the water table.

Q3: What's a typical angle of internal friction?
A: For sands: 30-40°, for clays: 10-20°. This depends on soil type and density.

Q4: When would I adjust the safety margin?
A: Increase margin for critical structures or when soil properties are uncertain.

Q5: What if I get F_s < 1?
A: This indicates potential instability. Consider slope flattening or soil improvement.