CONVENTIONAL METHODS TO EVALUATE SHEAR WAVE TRAVEL-TIME IN LABORATORY TESTS

The evaluation of shear wave velocity in soil is so much desirable in geotechnical engineering due to its application to estimate the soil moduli under small strain condition. Obtaining the best travel-time is a main concern in calculating shear wave velocity in laboratory tests. Correct travel-time might be masked by some unwanted phenomena such as near-effect. In present paper, basic parameters and specific application of different methods toexamine shear wave travel-time i.e. temporal, mathematical, and frequency methods are explained and their exactitude are comprised. Based on authors’ laboratory tests on granular soils, maximum difference between different temporal method results is reached up to 0.09 ms. Cross-correlation presents its best results when the first peak of the received signal is the greatest between all next peaks. The frequency method was completely explained since the results of different method results to evaluate the most correct travel-time is converged using this process

Keywords:

Granular soil , Shear Wave Velocity , Travel-time , Cross-correlation Function , Frequency Methods