Much information has been generated from in situ soil tests conducted over the last two decades. Because of variations in mechanical and procedural details and the intended use of these tests, the information can be too specific, fragmented, or sometimes difficult to interpret. There is a need to gather and present this information on a common basis. The work presented in this paper introduces a practical approach that aims to address part of this need and to incorporate some in situ parameters in preliminary estimations for pavement design. The results of the study are preliminary. Nevertheless, the impact is twofold: the study is an initial effort to gather and present various in situ test information on a common basis and introduces direct utility of some in situ test parameters in broad estimation of bearing parameters in pavement design. The results of a great number of tests have been used to establish correlations between some in situ tests, and also to establish correlations between in situ parameters and soil properties. The well-known correlations are those between cone penetration (CPT) and standard penetration (SPT) tests, and between the soil type and the cone penetration, dilatometer (DMT), and pressuremeter (PMT) parameters. Four such correlations were incorporated into an existing design chart that included approximate interrelationships between soil classification, modulus of subgrade reaction, and California bearing ratio (CBR). The new correlations (SPT, CPT, PMT) were based on soil classification.
Abstract