Recreation of Small Strains Phenomenon under Pavement Structure and Consequences of Failure to Address It

Abstract

Abstract. This paper describes the small strains phenomenon which occurs in the subgrade under a pavement, a phenomenon documented through in-situ tests and recreated in numerical analyses, which lends a practical engineering aspect to the subject matter. The analyses were preceded by: 1) presentation of the role of constitutive models in structure-subgrade system analysis, 2) reference to methods of modelling in mechanistic procedures and possibility of reliable assessment of criterial values in road structures. These studies were coupled with a description of field tests, which recorded strains in subgrade under a loaded pavement: in zone I directly under the pavement -variable, depending on stiffness of the pavement and the load (about 200÷1000.10-6) and below that, in zone II -'stabilised' (about 1÷5.10-6). In summary, it has been found that the accuracy of numerical analyses of structure-subgrade systems is dependent on the adopted constitutive model of the soil and the numerical calculation area representing the subgrade. Recreation and analysis of the pavement-subgrade system behaviour employed the MCC(OC) critical state model. It was determined that a reliable response of the computational model to the load path used can be obtained with a model that has been previously properly calibrated. The paper justifies the need to carry out further, directed field tests, coupled with numerical analyses employing relevant constitutive models for description of the soil's performance.

Description of Limit States in the Subsurface Layer of Loosened Subsoil in View of Critical State Soil Mechanics

“…Nowadays, numerical analyses play an increasingly important role in designing and assessing the construction structure and phenomena occurring in subsoil [ 25 , 26 , 27 ]. For example, Shu et al [ 25 ] used different constitutive models to recreate undisturbed subsoils’ stress–strain strength characteristics.…”

“…For example, Shu et al [ 25 ] used different constitutive models to recreate undisturbed subsoils’ stress–strain strength characteristics. Kadela and Fedorowicz [ 26 , 27 ] and Kadela [ 28 ] used the MCC model to recreate the subsoil behaviour of the road pavement-subsoil system under the real load from the vehicle wheels. Nascimbene [ 29 ] attempted to recreate the influence of seismic earthquakes on the building.…”