The cone penetration test (CPT) has been widely used in Chile in the last decade, being one of the preferred tests on mining waste, highlighting its application in tailings. One of the primary uses of CPTs lies in assessing soil type and stratigraphy, however most of the existing correlations widely used in practice were not calibrated for these heterogeneous manmade soils and do not differentiate if soil is in a saturated state or not.
In this paper, the CPT-based soil classification correlations proposed by Robertson (1990), Jefferies & Davies (1991), Eslami & Fellenius (1997), Shuttle & Cunning (2008), Robertson (2010), and Robertson (2016) are evaluated using real CPT data from copper mine tailings. Each estimation is compared with the Unified Soil Classification System (USCS) results obtained in the laboratory from MOSTAP samples collected from twin boreholes associated with each CPT.
Sands are typically classified accurately by most methods, although it should be noted that there are relatively few sandy samples in analysis. The methods proposed by Robertson (2010, 2016) and Eslami & Fellenius (1997) consistently yield reliable classifications. Soils classified as low plasticity silts are not consistently grouped clearly in the classification charts, but the charts by Robertson (2010) and Eslami & Fellenius (1997) appear to distinguish these soils more effectively.
Based on the results, it is observed that the degree of saturation does not have a major impact on the precision of the different methodologies in estimating soil type.
