Experimental observations and theoretical predictions of shakedown in soils under wheel loading

摘要

Shakedown is the term given to the state of a structural system subjected to cyclic loading whenits response has become resilient in nature and no further accumulation of plastic strains occurs. An experimentalstudy was conducted with a view to observing the shakedown phenomenon of various soils and granular materialsunder moving wheel loading. The experiments were conducted using two laboratory wheel tracking devices withtest specimens compacted into moulds. The results are presented along with the theoretical predictions derivedfrom parallel work based on use of a lower bound theory. Monotonic triaxial tests were conducted to determinethe Mohr-Coulomb failure parameters, as these formed part of the input for the theoretical predictions. Thepermanent deformation, which developed under the wheel as loading progressed, was monitored. Three types ofresponse were identified, from which, a range of values for measured shakedown were identified. These werefound to compare reasonably well with the theoretical predictions.