Can I use the One-Step Method if the soil varies significantly in the compacted layer?
Yes. In situations where soils being tested are relatively uniform, the One-Step Method is quick and easy to use. However, where the soils vary significantly from those used in establishing the calibration factors, a simple field calibration adjustment can improve test accuracy. The calibration adjustment involves taking a sample of the soil with a water content similar to that associated with insitu conditions, compacting it into a compaction mold with standard compaction energy (ASTM D 698), making a measurement of the weight to obtain the total density of the soil in the mold, and then taking readings of the soil in the mold with the TDR to obtain values of Ka, and ECb. Research is continuing to establish the accuracy and reliability of the adjusted calibration factors by these procedures. (Excerpted from: Drnevich, V.P., “New Uses of TDR, Drnevich, GeoFrontiers Conf., ASCE, June 30,2004, 16 pages.
Yes. In situations where soils being tested are relatively uniform, the One-Step Method is quick and easy to use. However, where the soils vary significantly from those used in establishing the calibration factors, a simple field calibration adjustment can improve test accuracy. The calibration adjustment involves taking a sample of the soil with a water content similar to that associated with insitu conditions, compacting it into a compaction mold with standard compaction energy (ASTM D 698), making a measurement of the weight to obtain the total density of the soil in the mold, and then taking readings of the soil in the mold with the TDR to obtain values of Ka, and ECb. Research is continuing to establish the accuracy and reliability of the adjusted calibration factors by these procedures.
