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The Coefficient of Permeability at 20° C refers to the measure of a porous medium's ability to allow fluid flow through its voids. It is a key parameter in geotechnical engineering and hydrogeology for understanding fluid movement through soils and rocks.
The calculator uses the permeability formula:
Where:
Explanation: The formula calculates the permeability coefficient based on the flow rate through a cross-sectional area under a constant hydraulic gradient.
Details: Accurate permeability calculation is crucial for designing drainage systems, predicting groundwater flow, assessing soil stability, and designing foundations and earth structures.
Tips: Enter discharge in m³/s, cross-sectional area in m², constant head difference, and length in meters. All values must be positive and non-zero.
Q1: What is the typical range of permeability values for different soils?
A: Permeability varies widely: gravel (10⁻¹-10⁻² m/s), sand (10⁻³-10⁻⁵ m/s), silt (10⁻⁶-10⁻⁸ m/s), clay (10⁻⁸-10⁻¹¹ m/s).
Q2: Why is temperature specified at 20°C?
A: Permeability measurements are standardized at 20°C to eliminate viscosity variations that occur with temperature changes.
Q3: What types of permeameter tests are commonly used?
A: Constant head test (for high permeability soils) and falling head test (for low permeability soils) are the two main methods.
Q4: How does soil composition affect permeability?
A: Grain size, shape, packing, and uniformity significantly influence permeability - larger, well-rounded grains typically have higher permeability.
Q5: Can this calculator be used for field measurements?
A: This calculator uses the constant head method formula, which is primarily for laboratory permeameter tests under controlled conditions.