STRESS STRAIN AND DISPLACEMENT DISTRIBUTIONS IN CROSS-ANTISOTROPIC AND TWO-LAYER ISOTROPIC ELASTIC SYSTEMS

THE EVIDENCE SUGGESTING ANISOTROPIC STRESS-STRAIN BEHAVIOUR OF SOILS AND PAVEMENT MATERIALS IS DISCUSSED AND THE EXISTING THEORECTICAL SOLUTIONS FOR CROSS-ANISOTROPIC AND TWO-LAYER ISOTROPIC SYSTEMS ARE REVIEWED. BASIC ELASTIC THEORY IS PRESENTED FROM THE POINT OF VIEW OF OBTAINING SOLUTIONS FOR THE DISPLACEMENTS RATHER THAN SOLVING FOR A STRESS FUNCTION. A FINITE DIFFERENCE METHOD HAS BEEN EXTENDED TO INCLUDE CROSS-ANISOTROPIC SYSTEMS AND TWO LAYER ISOTROPIC SYSTEMS. IN BOTH CASES THE MATERIAL PROPERTIES CAN VARY WITH DEPTH. A SECOND METHOD OF SOLVING TWO LAYER ISOTROPIC SYSTEMS IS PRESENTED. THIS METHOD INVOLVES THE NUMERICAL INTEGRATION OF FUNCTIONS OF BESSEL FUNCTIONS AND IS LIMITED TO THE CONDITIONS OF HOMOGENEITY WITHIN THE LAYERS. THE EXTERNALLY APPLIED NORMAL AND SHEAR LOADING STRESSES FOR BOTH THE FINITE DIFFERENCE METHOD AND THE BESSEL FUNCTION METHOD ARE APPLIED OVER A CIRCULAR AREA AND CAN BE DEFINED AS ANY SYMMETRIC DISTRIBUTIONS. THE TECHNIQUES USED IN DEVELOPING COMPUTER PROGRAMS ARE DISCUSSED AND RESULTS ARE PRESENTED WITH PARTICULAR REFERENCE TO PAVEMENTS. /RRL/(A)