ABSTRACT
Commonly used tests are discussed for the assessment of soil and rock strength. Strain compatibility must be considered in design as the peak, ultimate and residual strengths are quite different. Compaction stress improves soil strength by first providing an improved confinement while reducing the air voids. The CBR is an empirical index test used to inform the pavement design on subgrade and pavement material properties. The CBR laboratory test may not represent the in-situ condition, although the soaked test models potential change conditions. Tests such as the PLT, DCP, and LFWD are useful field tests and offer benefits beyond the traditional density and CBR tests. Two case studies are used to show (1) CBR subgrade assessment when the laboratory value did not apply and (2) the errors associated in using on situ SPT N-value as design values. Rock mass strength is dependent on its intact strength and structure. Intact rock strength may degrade with exposure. The geology affects the durability of the source material.
