REPEATED-LOAD BEHAVIOR OF GEOSYNTHETIC-BUILT UNBOUND ROADS

In a study of the working load behaviour of unbound roads, small-scale models of unbound, geosynthetic-built road sections, constructed on r econstituted, milled horticultural peat subgrades, were tested in plan e strain under repeated loads. The results of load tests on the peat s ubgrades were used to derive an appropriate relation for the coefficie nt of peat subgrade reaction (or stiffness), which was input to a prev iously derived three-parameter mechanical analogue for the road sectio ns, in order to predict road section stiffness. The validity of the mo del was checked by comparing its predictions for surface displacements under loading against those observed in the tests. The predicted disp lacements being sufficiently accurate, it was concluded that using the simple three-parameter model for unbound geosynthetic-built road sect ion repeated-load behaviour is an appropriate approach for the design of such roads from the stiffness point of view.