BACKWARD CALCULATION OF INCIDENT SEISMIC WAVE BASED ON EFFECTIVE STRESS ANALYSIS

We propose a methodology to retrieve the up-going (incident) component of ground motion from borehole records by applying a backward calculation based on an effective stress analysis. Most of the available techniques to date are based on an equivalent linear analysis that is not accurate in cases of strong non-linearity. Numerical examples are conducted to examine the accuracy of the identified incident wave in cases of liquefaction. It is concluded from the results as follows: 1) The incident wave, as well as the stress-strain hysteresis and effective stress path of a liquefied layer, is retrieved from the noiseless record with high accuracy. 2) In case the observed record is not given at the sufficient depth, the accuracy of identified incident wave will decrease. 3) The proposed methodology can be applied to the records with white noise.