Measurement of dynamic properties of stiff specimens using ultrasonic waves

2011 ◽  
Vol 48 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Zahid Khan ◽  
Giovanni Cascante ◽  
M. Hesham El Naggar
Keyword(s):  
Shear Wave ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Ultrasonic Waves ◽  
Resonant Column ◽  
Reliable Determination ◽  
Cemented Sand ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Ultrasonic Equipment

The measurement of low-strain properties (wave velocity and damping ratio) of geomaterials is affected by equipment-generated delays, coupling of transducers, and wave reflections. This study presents a new technique to measure ultrasonic properties of stiff specimens accurately. Compressional-wave velocities in cylindrical rods of different lengths and materials were measured using different ultrasonic equipment. The error induced by different equipment was below 1% after the measurements were corrected by the equipment time delay. Shear-wave velocities of different materials were measured using ultrasonic transducers (frequency < 1 MHz) and a resonant column device (frequency < 200 Hz). The difference in shear-wave velocities was less than 4%, and the measured values are in agreement with published results for all tested materials. A new methodology based on the first two reflections of the main pulse has been developed to measure the damping ratio of stiff specimens using ultrasonic equipment. The ultrasonic measurements of the damping ratio compare well with resonant column results. A more reliable determination of the dynamic Poisson’s ratio of a cemented sand was achieved using corrected ultrasonic-wave velocities.

ULTRASONIC SHEAR‐WAVE VELOCITIES IN ROCKS SUBJECTED TO SIMULATED OVERBURDEN PRESSURE

Geophysics ◽  
1962 ◽  
Vol 27 (5) ◽  
pp. 590-598 ◽  
Author(s):  
M. S. King ◽  
I. Fatt
Keyword(s):  
Shear Wave ◽  
High Pressures ◽  
Applied Pressure ◽  
Ultrasonic Energy ◽  
Overburden Pressure ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Ultrasonic Equipment ◽  
The One ◽  
Ultrasonic Shear

Ultrasonic equipment has been developed to measure shear‐wave velocities in small rock samples at hydrostatic pressures up to 2,400 psi. Under certain optimum conditions dilatational wave velocities can also be determined. The method employs a beam of ultrasonic energy passing through a liquid in which a quarter‐inch‐thick parallel‐sided sample of rock is rotated. From the laws of classical optics for the refraction and reflection of waves at boundaries between dissimilar media and the known velocity of sound in the liquid, the velocities in the sample may be calculated from a record of ultrasonic energy transmitted through the sample as a function of angle between the sample and the ultrasonic beam. Results obtained with this apparatus from samples of materials for which the velocity of waves has been published show good agreement with the latter. The variation of the velocity of shear waves in dry rocks with applied hydrostatic pressures up to 2,400 psi have been measured for seven sandstones, a chalk, and a limestone. The shear‐wave velocities were found to increase with an increase of the applied pressure. For five of the sandstones the increase in velocity at high pressures approached the one‐sixth power of the applied hydrostatic pressure predicted theoretically for a sphere pack model.

scholarly journals Evaluation of Dynamic Properties of Sodium-Alginate-Reinforced Soil Using A Resonant-Column Test

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2743
Author(s):  
Seongnoh Ahn ◽  
Jae-Eun Ryou ◽  
Kwangkuk Ahn ◽  
Changho Lee ◽  
Jun-Dae Lee ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Sodium Alginate ◽  
Shear Failure ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Reinforced Soil ◽  
Resonant Column ◽  
Column Test ◽  
Alginate Solution ◽  
Resonant Column Test

Ground reinforcement is a method used to reduce the damage caused by earthquakes. Usually, cement-based reinforcement methods are used because they are inexpensive and show excellent performance. Recently, however, reinforcement methods using eco-friendly materials have been proposed due to environmental issues. In this study, the cement reinforcement method and the biopolymer reinforcement method using sodium alginate were compared. The dynamic properties of the reinforced ground, including shear modulus and damping ratio, were measured through a resonant-column test. Also, the viscosity of sodium alginate solution, which is a non-Newtonian fluid, was also explored and found to increase with concentration. The maximum shear modulus and minimum damping ratio increased, and the linear range of the shear modulus curve decreased, when cement and sodium alginate solution were mixed. Addition of biopolymer showed similar reinforcing effect in a lesser amount of additive compared to the cement-reinforced ground, but the effect decreased above a certain viscosity because the biopolymer solution was not homogeneously distributed. This was examined through a shear-failure-mode test.

Soil moisture assessment by means of compressional and shear wave velocities: Theoretical analysis and experimental setup

Measurement ◽  
2010 ◽  
Vol 43 (3) ◽  
pp. 344-352 ◽  
Author(s):  
F. Adamo ◽  
F. Attivissimo ◽  
L. Fabbiano ◽  
N. Giaquinto ◽  
M. Spadavecchia
Keyword(s):  
Soil Moisture ◽  
Theoretical Analysis ◽  
Shear Wave ◽  
Experimental Setup ◽  
Wave Velocities ◽  
Shear Wave Velocities
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