Three-dimensional finite element analysis for determining subgrade reaction modulus of subgrade soils

The success of any pavement system is depending on the strength of the subgrade layer that represents a foundation on which unbound and surface course layers are placed. The strength of the subgrade layer is often defined in terms of a subgrade reaction modulus (Ks) which is typically obtained from the static plate load test (PLT). The PLT test is known to be laborious, time-consuming and relatively expensive, therefore several alternative methodologies for predicting (Ks) are required. The objective of this research is developing a 3D-finite element model using Plaxis 3D software to simulate the plate load tests, and comparing the finite element results with those obtained from experimental tests. Twenty-seven plate load tests were carried out on three different types of subgrade soils. The soils collected from different sites in Kerbala city and tested under static load under three degrees of compaction. The experimental results were verified numerically using the finite element method. In the numerical simulation, the Mohr-Coulomb model was used to represent the behavior of soil. The numerical and experimental results were analyzed and compared. The results showed a good agreement with experimental work, also showed the possibility of using Plaxis 3D in the simulation of the static plate load test.