Hydro-mechanical behaviour of unbound granular materials in road pavements and embankments

• Research unit: COST
• Project number: C04.0021

Key words (English)

Thermo-hydro-mechanical behaviour; unsaturated soils; constitutive modelling; elasto-plasticity; experimental tests; finite element modelling; environmental geomechanics

Research programs (English)

COST-Action 351 - Water Movement in Road Pavements and Embankments

Short description (English)

The main objective of this project is to increase the knowledge of the hydro-mechanical behaviour of unbound granular materials in road pavements and embankments by:i) Identification of water movement and moisture conditions in unbound pavement and sub-grade layers under various hydraulic conditions. ii) Investigation of the relationship between the mechanical behaviour of material/soil and their moisture conditions. iii) Numerical modelling of water movement in road pavements and embankments. iv) Investigation of the hydro-mechanical coupling in road pavements and embankments

Partners and International Organizations (English)

BE, HR, CZ, DK, FI, FR, EL, IS, NO, PL, PT, RO, CS, SI, ES, SE, CH, GB

Abstract (English)

THE RESEARCH TREATS MAINLY ON THE MECHANICAL BEHAVIOUR OF UNSATURATED FINE SOILS UNDER NON-ISOTHERMAL CONDITIONS. IN PARTICULAR, THREE MAIN POINTS ARE ADDRESSED: (I) THE CONSTITUTIVE MODELLING, (II) THE LABORATORY EXPERIMENTAL TESTS AND (III), AS APPLICATION, THE SIMULATION OF BOUNDARY VALUE PROBLEMS WITH THE FINITE ELEMENT METHOD. (I) THE MAIN PROBLEM RELATED TO THE ELABORATION OF A THERMO-HYDRO-MECHANICAL MODEL FOR UNSATURATED SOIL (THM) IS TO EXTRACT THE DIFFERENT COUPLING EFFECTS EXISTING BETWEEN THERMAL, HYDRIC AND MECHANICAL BEHAVIOUR. THE CONTRIBUTION OF THE RESEARCH IS TO JOIN THE SEPARATED (T,H,M) MODELS IN A SINGLE COUPLED AND UNIFIED THM MODEL TAKING INTO ACCOUNT THE MAJOR COUPLING EFFECTS. (II) THE THERMO-HYDRO-MECHANICAL TESTS (MAINLY OEDOMETRIC AND ISOTROPIC) IN WHICH SUCTION, TEMPERATURE AND EXTERNAL LOAD ARE CONTROLLED ENABLE TO VALIDATE THE HYPOTHESES TAKEN IN THE MODEL AND TO UNDERLINE THE THM COUPLING EFFECTS. (III) THE FINAL GOAL OF THIS RESEARCH HAS BEEN TO STUDY THE MECHANICAL BEHAVIOUR OF GEOSTRUCTURES SUBMITTED TO ENVIRONMENTAL LOADINGS. SO, THE ELABORATED MODEL HAS BEEN IMPLEMENTED IN A FINITE ELEMENT CODE TO SIMULATE BOUNDARY VALUE PROBLEMS. IN PARTICULAR, THE EFFECTS RELATED TO THE ROAD SUBGRADES DISTURBANCE DUE TO TRAFFIC LOAD AND CYCLIC CLIMATIC CHANGE IS ANALYSED. VERY FEW UNIFIED STUDIES TAKING INTO ACCOUNT THERMO-HYDRO-MECHANICAL COUPLING EFFECTS HAVE BEEN DONE IN THE PAST. SO, THANKS TO THESE THREE COMPLEMENTARY APPROACHES, THIS STUDY BRIGHT IMPORTANT ADVANCEMENTS IN THE UNDERSTANDING AND MODELLING OF SUCH THERMO-HYDRO-MECHANICAL PHENOMENON OCCURRING IN FINE SOILS.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C04.0021