Dynamic field assessment of bearing capacity for pavement subgrades and foundations

In situ assessment of bearing capacity is usually performed by means of static plate loading tests. Today, however, higher performance dynamic investigation methodologies are increasingly often employed, in combination with traditional and deflectometric techniques. This allows a large amount of data to be recorded rapidly, thereby guaranteeing more detailed investigation, but also making the process of data elaboration and result interpretation more time-consuming. In the present study, an improvement in data elaboration techniques and interpretation of results was achieved through application of geostatistical science to measurement and analysis of data acquired at several experimental sites. The findings suggest that geostatistics-based systems have the potential for use as quality control/quality assurance (Qc/Qa) devices in testing subgrades, subbase courses and compacted soil layers and as a means of evaluating their correspondence to the strength performances required for the layers. Concomitant use of various deflectometric systems also made it possible to take specific construction and operating characteristics of the devices into account when evaluating the experimental results. This paper reports on joint experiences conducted by the Universities of Pisa and Bologna, whose research teams have long been working on validation of innovative field testing systems. The results appear promising for upcoming insertion of the methodologies inserted into existing technical specifications.