Laboratory Measurement of Total Porosity in Unconsolidated Quartz Sand by Two Integrated Methods

摘要

Accurate measurements of porosity in unlithified sediments have long been difficult and subject to errors caused by inconsistent compaction in various laboratory methods. Two different methods, volumetric saturation and bulk density comparison, were used to measure the total porosity of 100 samples of well-sorted beach and dune sands. Five replicate measurements were made to determine the comparative precision and accuracy found within the two methods and how they compare to each other. The standard deviation of the 100 samples with 5 replicate measurements for the volumetric saturation measurement was 0.004 and with the bulk density comparative method was 0.003. Comparison of the total porosity measurements made using the different methods allows a determination to be made to ascertain if the sample meets the condition of monomineralic composition (close to 100% quartz sand) for accurate measurement using the bulk density comparison method. The comparative error maximum was set at 3% which resulted in 91 of the 100 samples meeting this criterion. A comparison of total porosity measurements of the 91 samples showed a mean error of 0.0638% which demonstrates the usefulness of using the two methods together to allow accurate measurement to be made and verified.