Characterization of volcanoclastic succession in South West Sardinia: In situ vs. laboratory assessment of compressional wave velocity

2022 ◽  
pp. 104533
Author(s):  
Arianna Maiu ◽  
Alberto Plaisant ◽  
Alberto Pettinau
Keyword(s):  
Wave Velocity ◽  
Compressional Wave ◽  
Compressional Wave Velocity ◽  
Laboratory Assessment ◽  
South West

DEPENDENCE OF IN‐SITU COMPRESSIONAL‐WAVE VELOCITY ON POROSITY IN UNSATURATED ROCKS

Geophysics ◽  
1972 ◽  
Vol 37 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Joel S. Watkins ◽  
Lawrence A. Walters ◽  
Richard H. Godson
Keyword(s):  
Wave Velocity ◽  
Seismic Refraction ◽  
Compressional Wave ◽  
Unconsolidated Sediments ◽  
Compressional Wave Velocity ◽  
Near Surface ◽  
Least Squares Fit ◽  
Water Saturated ◽  
Porosity Range

The relation of in‐situ compressional‐wave velocities to porosities, determined by seismic refraction for unsaturated near‐surface rocks from different areas in Arizona, New Mexico, and California, is grossly similar to relations determined by other investigators for water‐saturated rock and unconsolidated sediments. The principal difference is that in the porosity range 0.0–0.2, compressional waves travel somewhat more slowly in unsaturated rocks than in water‐saturated rocks, and much more slowly, in the porosity range 0.2–0.8. The function, ϕ=−0.175 ln (α)+1.56, where ϕ is the fractional porosity and α is the compressional‐wave velocity, was obtained as a least squares fit to the experimental data. Bulk densities are reported for all samples; moisture contents are reported in some instances.

Critical Insights in Laboratory Shear Wave Velocity Correlations of Clays

2021 ◽  
Author(s):  
Dania Elbeggo ◽  
Yannic Ethier ◽  
Jean-Sébastien Dubé ◽  
Mourad Karray
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Earth Pressure ◽  
Dynamic Parameter ◽  
Clay Deposits ◽  
Sample Disturbance ◽  
P Rat

Shear wave velocity is an important mechanical/dynamic parameter allowing the characterization of a soil in the elastic range (γ < 0.001 %). Thirty five existing laboratory correlations of small strains shear modulus or shear wave velocity were examined in this study and are grouped into different general forms based on their geotechnical properties. A database of 11 eastern Canadian clay deposits was selected and used for the critical insights. The effect of the coefficient of earth pressure at rest was also examined. A range of variation for each general form of correlation was determined to take the plasticity index and void ratio values of investigated sites into account. The analysis shows a significant scatter in normalized shear wave velocity values predicted by existing correlations and raises questions on the applicability of these correlations, especially for eastern Canadian clays. New correlations are proposed for Champlain clays based on laboratory measurement of shear wave velocity using the piezoelectric ring actuator technique, P-RAT, incorporated in consolidation cells. An analysis of P-RAT results reveals the sample disturbance effect and suggests an approach to correct the effect of disturbance on laboratory shear wave velocity measurements. The applicability of the proposed correlations, including the disturbance correction, is validated by comparison with in situ measurements using multi-modal analysis of surface waves (MMASW).

Sign in / Sign up

Export Citation Format

Share Document