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

Abstract

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.

Experimental and numerical analysis of triaxial compression test for a clay soil

“…The v value for unsaturated clay soil must be less than 0.35 according to Nieto Leal et al (2009). Unconsolidated clays showed a very low dilation, therefore, ψ can be considered as zero (Jawad et al, 2020). From these initial values, the parameters were adjusted for the simulations.…”

Structural Design of Field Plate Load Test Equipment to Determine In situ Bearing Capacity and Settlement of Clayey Soil

“…Invariably, large applied weight is required which cannot be applied directly without any form of load magnification, hence the introduction of a lever arm. The lever arm was designed and used to magnify the load applied to the device so as to achieve high applied stress [13][14][15][16]. The study by [17] which conducted a plate load test on the field where a load was applied to the plate through a hydraulic jack against a heavy kentledge of sandbags, in 5 equal load increments of 100 kPa is a typical example of field plate load test using hydraulic jack for load application.…”