To the question on the factors of formation of the sands density and their potential accounting by cone penetration test

Abstract

Undisturbed sampling of sands from boreholes is difficult. It is important to find methods for determining the sands density in-situ, in particular, by cone penetration test. According to the results of cone penetration test can be determined only the categories of relative density of sands depending on their size distribution and probing depth. Based on an extensive literary material and long-term studies of the authors were considered a number of factors, which form the natural density of sands with different particle size distribution and genesis. For improving the accuracy, it is necessary to consider not only the particle size distribution, but also morphological features of grains, primarily depending on the genesis. The most versatile and effective indicator of the morphological features of grains is generalized morphological index λ (by A.D. Potapov). Taking into account that the empirical formula for quantitative assessment of the sands density by cone resistance (by L.G. Mariupolskiy), in our opinion, applicable only for average-size sands without considering of their uniformity, genesis and generalized morphological index, content of silt and clay fraction, water saturation and presence of cohesion-hardening, we offer new correlations between dry soils density and cone resistance for different genetic types of sand.