Theoretical formulas that relate penetration depth of a test roller to strength properties of bases and subgrades are presented. The algebraic expressions, derived using the generalized bearing capacity formula employed regularly in geotechnical practice, specifically relate angle of internal friction and soil cohesion to the penetration depth of a towed, rigid wheel with a known force (weight) applied. The existence of such a relationship has the potential to reinvent test rolling as a quality assurance tool capable of providing a continuous record of in situ soil strength measurements along a roadway. Besides supplying a means for interpretation of test roller measurements, the proposed formulas provide a method for practitioners to investigate the influence of modifying test roller characteristics (such as reducing weight or changing wheel size) and to calibrate a test roller to be particularly sensitive to certain soils. The predictions show promising agreement with results from three-dimensional numerical simulation and experimental data.
Abstract