EFFECTIVENESS OF A REINFORCING GEOGRID IN A RAILWAY SUBBASE UNDER DYNAMIC LOADS

Following the unification of Germany it is urgently required to increase the bearing capacity of the existing railway routes in East Germany to take into account the increasing volume and speed of traffic. As a rule this can be achieved by a subgrade protective layer (SPL) which is spread between the subgrade and crushed-stone bed. In a fatigue loading test with 5 million load cycles it was found out that the bearing capacity of the SPL can be increased by reinforcing geogrids. The reinforced SPL showed an increase of 70% in bearing capacity compared with the unreinforced SPL. Moreover, the settlements were smaller, together with a flatter settlement curve.