MAXIMUM AND MINIMUM VOID RATIO CHARACTERISTICS OF SANDS

抄録

Characteristics of the maximum and minimum void ratios of sands and their possible use for material characterization have been investigated in this study. Data of over 300 natural sandy soils including clean sands, sands with fines and sands containing small amount of clay-size particles have been used to examine the influence of fines, grain-size composition and particle shape on e_max, e_min and void ratio range (e_max - e_min). A set of empirical correlations are presented which clearly demonstrate the link between these void ratios and material properties of sands. The key advantage of (e_max - e_min) over-conventional material parameters such as Fc and D₅0 is that (e_max - e_min) is indicative of the overall grain-size composition and particle characteristics of a given sand and that it shows off the combined influence of relevant material factors. The void ratio range provides a general basis for comparative evaluation of material properties over the entire range of cohesionless soils. Important issues related to the laboratory procedures used for determination of e_max and e_min as well as their applicability to fines-containing sands are also addressed. Three distinct linear correlations were found to exist between e_max and e_min for clean sands, sands with 5-15% fines and sands with 15-30% fines respectively, thus illustrating that the standard JGS procedures for minimum and maximum densities of sands can provide reasonably consistent e_max and e_min values for sands with fines content of up to 30%. The importance of the grain-size distribution and presence of gaps in the grading of composite soils or mixtures of sands with fines produced in the laboratory is also discussed.