Head given Neutral Stress per unit Area for Dams on Soft Foundations Calculator

Head Formula:

\[ h = \left(\frac{\sigma_{min}}{D \times W} - 1\right) \times L_{Travelpath} \]

Minimum Stress (σ_min):

Depth of Dam (D):

Specific Weight of Water (W):

kN/m³

Length of Travel Path (L_Travelpath):

Tolerance:

Head (h):

1. What is Head given Neutral Stress per unit Area?

Definition: This calculator determines the hydraulic head based on neutral stress distribution for dams built on soft foundations.

Purpose: It helps civil engineers assess the pressure distribution and stability of dams on compressible foundations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ h = \left(\frac{\sigma_{min}}{D \times W} - 1\right) \times L_{Travelpath} \]

Where:

\( h \) — Hydraulic head (meters)
\( \sigma_{min} \) — Minimum stress (Pascals)
\( D \) — Depth of dam (meters)
\( W \) — Specific weight of water (kN/m³, typically 9.81)
\( L_{Travelpath} \) — Length of seepage path (meters)

Explanation: The formula calculates the hydraulic head considering the stress distribution and water pressure in the foundation.

3. Importance of Head Calculation

Details: Accurate head calculation is crucial for assessing seepage forces, uplift pressures, and overall dam stability on soft foundations.

4. Using the Calculator

Tips: Enter all required parameters. The tolerance field (default ±5%) can be adjusted to see how variations affect the results.

5. Frequently Asked Questions (FAQ)

Q1: What is neutral stress in dam foundations?
A: Neutral stress refers to the pore water pressure within the foundation material that affects the effective stress and stability.

Q2: Why is specific weight of water typically 9.81 kN/m³?
A: This is the standard value for fresh water at 4°C, accounting for gravity (9.81 m/s²) and water density (1000 kg/m³).

Q3: How does travel path length affect the head?
A: Longer travel paths generally result in greater head loss and reduced uplift pressures.

Q4: When would I adjust the tolerance percentage?
A: Adjust for different safety factors, material uncertainties, or specific project requirements.

Q5: What's a typical range for minimum stress in dams?
A: Minimum stress varies widely but often falls between 50-500 kPa depending on dam size and foundation conditions.