1. What is Permeability for Dams on Soft Foundations?

Definition: This calculator determines the coefficient of permeability of soil for dams built on soft foundations, based on hydraulic gradient and unit head.

Purpose: It helps civil engineers assess the seepage characteristics of foundation soils beneath dams.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( k \) — Coefficient of permeability (m/s)
• \( Qt \) — Discharge from dam (m³/s)
• \( B \) — Number of beds (dimensionless)
• \( H_{Water} \) — Head of water (m)
• \( N \) — Number of equipotential lines (dimensionless)

Explanation: The formula relates the flow rate through the dam foundation to the hydraulic gradient and soil permeability.

3. Importance of Permeability Calculation

Details: Accurate permeability estimation is crucial for dam safety, preventing excessive seepage, and ensuring foundation stability.

4. Using the Calculator

Tips: Enter the discharge rate, number of beds, water head, and equipotential lines. The ±5% indicates typical measurement accuracy ranges.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical permeability range for soft foundations?
A: For soft clay foundations, permeability typically ranges from 10⁻⁶ to 10⁻⁹ m/s.

Q2: Why is permeability important for dam design?
A: It affects seepage rates, pore water pressures, and potential for piping failure in the foundation.

Q3: How does the number of beds affect permeability?
A: More beds typically indicate more flow paths, potentially increasing effective permeability.

Q4: What's the significance of the ±5% values?
A: This represents typical measurement uncertainty in field conditions for these parameters.

Q5: How can results be used in dam design?
A: Results help design cutoff walls, drainage systems, and assess seepage control measures.

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