Impact of reinforcement layer material and thickness on deflections measured in the static and dynamic plate load tests

Abstract

The bearing capacity and compaction values obtained in the plate load tests (the latter determined indirectly) often depend on the used test method: static - using static load test apparatus (VSS) or dynamic - using light weight deflectometer (LWD). Despite extensive comparative studies the correlation between two test methods still remains an issue. With the values obtained in the field tests and with the use of numerical calculations allowing for the impact of viscoplastic phenomena, the authors managed to demonstrate how big is the effect of not only the type of material, but also of the thicknesses of the reinforced subgrade layers on the discrepancy between the displacement values obtained with the two test methods in consideration. The behaviour of the subgrade material during the tests was verified using the finite element method. The share of elastic, plastic and creep strains in the total strain was determined for different layered systems and thicknesses.