This research work had the aim of developing a procedure for back-calculating accurate and precise parameter values, describing the mechanical behaviour of the materials built in an existing road structure. After reviewing the existing testing techniques, a new device was designed and assembled at the IGT, Institute for Geotechnical Engineering (ETH Zürich) for measuring the three dimensional deflection bowl under a standard axle load (SAL). Particular attention was paid for obtaining precise and accurate significant measurements for inverse analysis. Three field tests on different locations and road structures were carried out: a flexible pavement type built in a concrete pit (indoor facility) at the EPFL (Ecole Polytechnique Federale de Lausanne), a semirigid type in Hinwil (Switzerland) and a flexible type in Bellinzona (Hinwil). The tests results show that the measured road displacements under a SAL, for relatively low temperatures, are generally reversible and time independent. Laboratory tests (uniaxial compression) were carried out on cores obtained from field samples.
The strain measurements of the loaded samples were carried out with strain gages, and validated against devices with different technology (LVDT). The analysis of the test results showed that the materials have different bulk and deviatoric stress-strain behaviour. A new thermodynamical framework for non linear viscoelasticity (hyperviscoelasticity) was developed. Experimentally validated hyperviscoelastic and hyperelastic constitutive laws were adopted respectively for describing the mechanical behaviour of asphalt and cement stabilized mixtures. The inverse analysis of the field tests results was carried out with two different optimization algorithms (Levenberg Marquardt and Mesh Adaptative Direct Search), the FE program ABAQUS, and the developed user defined models. The results demonstrate the accuracy and precision of the parameter values obtained with the proposed inverse analysis procedure, demonstrating a potential for application of the developed technique for non destructing testing of real road structures.
Reihe
Auflage
Sprache
Verlagsort
Zielgruppe
Für höhere Schule und Studium
Für Beruf und Forschung
Illustrationen
zahlr. Abb, z.T. farbig
zahlr. Abb, z.T. farbig
Maße
Höhe: 29.7 cm
Breite: 21 cm
Gewicht
ISBN-13
978-3-7281-3274-1 (9783728132741)
Schweitzer Klassifikation
Chapter 1: Inverse Analysis in Road Geotechnics
1.1 Introduction (a)
1.2 Introduction (b)
1.3 Testing devices for inverse analysis
1.4 Conclusions
Chapter 2: ETH Delta Design
2.1 ETH Delta
2.2 Structural Design
2.3 Measuring sensors
2.4 Test procedure
2.5 Optimized device design for inverse analysis
2.6 Calibration procedure
Chapter 3: ETH Delta Field Tests
3.1 Introduction
3.2 Field tests at Halle Fosse (LAVOC, EPFL)
3.3 Field tests at Hinwil (MLS10)
3.4 Field tests in Bellinzona
3.5 Conclusions
Chapter 4: Laboratory Tests
4.1 Introduction
4.2 Strain gage measurements of small strains
4.3 Triaxial stress-strain space
4.4 Laboratory tests on EPFL materials
4.5 Laboratory tests on Hinwil cores
4.6 Laboratory tests on Bellinzona cores
4.7 Conclusions
Chapter 5: Constitutive Modeling of Road Materials
5.1 Introduction
5.2 Background
5.3 Thermomechanical framework for hyperviscoelasticity
5.4 Energy function for a power law viscoelastic model
5.5 A generalized family of hyperviscoelastic models
5.6 A hyperviscoelastic model for granular materials with pressure dependent bulk stiffness
5.7 Validation of the hyperviscoelastic constitutive model
5.8 Hyperelastic modeling of cement stabilized base material
5.9 General stress-strain state formulation and index notation
5.10 The finite element implementation
5.11 Validation of the implemented subroutine UMAT
5.12 Conclusions
Chapter 6: Field Tests Validation
6.1 Introduction
6.2 Introduction on inverse analysis
6.3 Inverse analysis of the EPFL (LAVOC) test site results
6.4 Inverse analysis of the Hinwil test site results
6.5 Inverse analysis of the Bellinzona test site results
6.6 Conclusions
Chapter 7: Summary and Conclusions
7.1 Summary
7.2 General conclusions
Literature
Appendix
