Feasibility of laser scanning to determine volumetric properties of grained fine soils

This study analyses the real applicability of laser scanning techniques to determine bulk densities of fine grained soils. The method, fast and accurate, can be employed both in the field and laboratory. The technique was calibrated with benchmarks and then applied to measure volumes of small samples of a specific silty soil of well-known properties (granite sawdust); next transformed into bulk densities from the sample-weights. The results are compared against those obtained from their precursor specimens, made using the Standard Proctor test. Before calculating soil sample volumes, optimum conditions for data acquisition, exportation and post-processing were assessed. The laser scanning provides highly consistent results when compared with those obtained from Standard Proctor compaction tests. However, the study shows a limiting value of moisture content below which the laser scan provides inaccurate results. Likely, this limit varies from soil to soil and therefore the technique must be calibrated before being used to determine bulk densities and derived volumetric properties (i.e., porosity or void ratio). Accordingly, this work presents a helpful procedure to evaluate the applicability of the laser scanning based on the detection of the limiting water content, which considers as well anomalies derived from compositional heterogeneities or external electromagnetic interferences.