__full__: Astm D338518 Pdf

= Time duration of the specific interval (hours or minutes).

| Error | Consequence | Prevention | |-------|-------------|------------| | | Overestimates infiltration | Ensure outer ring water level equals inner ring level at all times. | | Ring driving smearing | Reduces vertical permeability | Drive rings smoothly, avoid over-hammering. Use sharpened ring edges. | | Temperature variation | Changes water viscosity | Record water temp; apply viscosity correction (provided in the standard). | | Trapped air | Hinders infiltration | Pre-saturate surface or use de-aired water. | | Insufficient test duration | Reads transient, not steady-state rate | Continue until rate stabilizes (can take hours in clays). |

: Unlike falling-head tests, this standard mandates maintaining a constant liquid level in both rings. The volume of liquid added to the inner ring to keep this level constant is the measurement used to calculate the infiltration rate. Applicability Limits

Precision, bias, and revisions

Knowing the infiltration rate is crucial for many applications. According to the standard, it has "application to such studies as liquid waste disposal, evaluation of potential septic-tank disposal fields, leaching and drainage efficiencies, irrigation requirements, water spreading and recharge, and canal or reservoir leakage".

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Acts as a hydraulic barrier. The water infiltrating from the outer ring saturates the surrounding soil, forcing the water in the inner ring to flow strictly downward in a vertical direction. astm d338518 pdf

Forces the water within it to flow strictly vertically. Measurements are taken exclusively from the inner ring to isolate the true, one-dimensional vertical infiltration rate. Technical Specifications and Equipment

The values stated in SI units are regarded as the standard. Inch-pound units given in parentheses are mathematical conversions provided for information purposes only and are not considered standard.

: Only the volume of water added to the inner ring is used to calculate the infiltration rate. The outer ring acts as a buffer to ensure water from the inner ring flows vertically into the soil, preventing lateral spread. = Time duration of the specific interval (hours or minutes)

Serves as the actual measurement zone. Because lateral flow is restricted by the outer ring's buffer, the water drop in the inner ring reflects true, one-dimensional vertical infiltration. Technical Specifications and Apparatus

– Terminology Relating to Soil, Rock, and Contained Fluids D1452 – Practice for Soil Exploration and Sampling by Auger Borings D2216 – Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass D2488 – Practice for Description and Identification of Soils (Visual-Manual Procedures) D3740 – Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction D5093 – Test Method for Field Measurement of Infiltration Rate Using a Double-Ring Infiltrometer with a Sealed-Inner Ring D5126 – Guide for Comparison of Field Methods for Determining Hydraulic Conductivity in the Vadose Zone