Evaluation of the Specimen Disturbance Effects in the Consolidation Test Using Shear Wave Velocity

Abstract

The effects of specimen disturbance on determining of various soil properties are one of the most challenging issues in geotechnical engineering. Types of disturbance mechanisms were generated in consolidation test. One of the important parameters in computing of consolidation settlement is the compression index (Cc). So that the effects of disturbance in the soil specimen reduced the amount of this parameter and could have a significant effect on the settlement calculations. Main propose of this study is evaluation of disturbance effects on Cc with using shear wave velocity. Study area was Tabriz in located in the northwest of Iran with different silty and type of clayey soils such as yellow, green, and gray marls have a significant consolidation potential. In this research, three boreholes drilled and twenty intacy samples obtained. Also, Shear wave velocity in field and laboratory was determined respectively with performing down hole and bender element (in situ effective confining stress) tests. In continue, the quality of all specimens were evaluated by five recent methods. Then, the correlation between the common specimen evaluation methods new process based on shear wave velocity values with the calculation of statistical coefficients were computed. Results showed that, shear wave velocity values before and after consolidation with in situ effective stress could a new evaluation criterion provide for the definition of sample quality (Q). Also, the compression index as well as pre-consolidation pressure for disturbance effects were corrected by the estimation of the disturbance percent using shear wave velocity.