Harichandran, R. S., Mahmood, T., Raab, A., and Baladi, G. Y. (1994).

Harichandran, R. S., Mahmood, T., Raab, A., and Baladi, G. Y. (1994). "Backcalculation of pavement layer moduli, thicknesses and bedrock depth using a modified Newton method." In Nondestructive Testing of Pavements and Backcalculation of Moduli (Second Volume), ASTM STP 1198, H. L. Von Quintas, A. J. Bush and G. Y. Baladi (eds.) American Society for Testing and Materials, Philadelphia, PA, 68-82.

Abstract

A modified Newton method for the backcalculation of pavement layer moduli, thicknesses, and stiff layer depth from measured surface deflections is presented. The method is an iterative one and can use any mechanistic analysis program for forward calculations (presently an extended precision CHEVRON program is used for this purpose). This method has been implemented in a new backcalculation program nameMICHBACK. Several examples of backcalculation based on theoretical deflection basins generated by the extended precision CHEVRON program are presented, and the effect of errors in input layer thicknesses and stiff layer depth on the backcalculated moduli are studied. Moduli backcalculated byMICHBACK are compared with results obtained by the EVERCALC 3.0 and MODULUS 4.0 programs.