Evaluation of Shear Wave Velocity from Bender Elements Using Cross-correlation

2013 ◽  
Vol 36 (4) ◽  
pp. 20120125 ◽  
Author(s):  
David Airey ◽  
A. K. M. Mohsin
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Cross Correlation ◽  
Bender Elements

scholarly journals Warsaw Glacial Quartz Sand with Different Grain-Size Characteristics and Its Shear Wave Velocity from Various Interpretation Methods of BET

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 544
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas ◽  
Raimondas Šadzevičius ◽  
Rytis Skominas
Keyword(s):  
Grain Size ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Cross Correlation ◽  
Time Of Arrival ◽  
Bender Elements ◽  
Mean Grain Size ◽  
Curvature Coefficient ◽  
First Time

After obtaining the value of shear wave velocity (VS) from the bender elements test (BET), the shear modulus of soils at small strains (Gmax) can be estimated. Shear wave velocity is an important parameter in the design of geo-structures subjected to static and dynamic loading. While bender elements are increasingly used in both academic and commercial laboratory test systems, there remains a lack of agreement when interpreting the shear wave travel time from these tests. Based on the test data of 12 Warsaw glacial quartz samples of sand, primarily two different approaches were examined for determining VS. They are both related to the observation of the source and received BE signal, namely, the first time of arrival and the peak-to-peak method. These methods were performed through visual analysis of BET data by the authors, so that subjective travel time estimates were produced. Subsequently, automated analysis methods from the GDS Bender Element Analysis Tool (BEAT) were applied. Here, three techniques in the time-domain (TD) were selected, namely, the peak-to-peak, the zero-crossing, and the cross-correlation function. Additionally, a cross-power spectrum calculation of the signals was completed, viewed as a frequency-domain (FD) method. Final comparisons between subjective observational analyses and automated interpretations of BET results showed good agreement. There is compatibility especially between the two methods: the first time of arrival and the cross-correlation, which the authors considered the best interpreting techniques for their soils. Moreover, the laboratory tests were performed on compact, medium, and well-grained sand samples with different curvature coefficient and mean grain size. Investigation of the influence of the grain-size characteristics of quartz sand on shear wave velocity demonstrated that VS is larger for higher values of the uniformity coefficient, while it is rather independent of the curvature coefficient and the mean grain size.

Shear Strength Monitoring System Based on Measurement of Shear Wave Velocity and Moisture Content

2014 ◽  
Vol 635-637 ◽  
pp. 750-754
Author(s):  
Peng Hu ◽  
Qing Li ◽  
Yi Wei Xu ◽  
Nan Ying Shentu ◽  
Quan Yuan Peng
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Shear Wave ◽  
Monitoring System ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Elements ◽  
Strength Measurement ◽  
Soil Shear Strength ◽  
The Relationship

Expound the importance of soil shear strength measurement at mudslide hidden point to release the loss caused by the disaster, explain the relationship between shear wave velocity, moisture content and shear strength, design the shear strength monitoring system combining the shear wave velocity measured by Piezoelectric bender elements and moisture content.

Surface-mounted bender elements for measuring horizontal shear wave velocity of soils

2008 ◽  
Vol 9 (11) ◽  
pp. 1490-1496 ◽  
Author(s):  
Yan-guo Zhou ◽  
Yun-min Chen ◽  
Yoshiharu Asaka ◽  
Tohru Abe
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Horizontal Shear ◽  
Bender Elements

Discussion “Measuring Shear Wave Velocity Using Bender Elements” by Leong, E. C., Yeo, S. H., and Rahardjo, H.

2006 ◽  
Vol 29 (5) ◽  
pp. 100382 ◽  
Author(s):  
L David Suits ◽  
TC Sheahan ◽  
J-S Lee ◽  
J Carlos Santamarina
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Elements

scholarly journals Surface and shear-wave velocity modelling of the Tongariro Volcanic Centre, New Zealand, using ambient noise cross-correlation

2021 ◽  
Author(s):  
◽  
Holly Joanne Godfrey
Keyword(s):  
Rayleigh Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Love Wave ◽  
Ambient Noise ◽  
Cross Correlation ◽  
Velocity Structure ◽  
Wave Velocities ◽  
Group Velocities

<p>We use continuous seismic data from permanent and temporary, broadband and short-period stations that were operating during 2001 and 2008 to investigate the subsurface velocity structure of the Tongariro Volcanic Centre (TgVC) of New Zealand, particularly the highly active but poorly understood Ruapehu and Tongariro Volcanoes.  Stacks of cross-correlation of two concurrent ambient noise seismograms can be used to estimate the interstation Green's Function, i.e., the impulse response of the earth between the two receivers. The Green's Functions are used to retrieve the dispersion relation (frequency-dependent velocity) of surface waves at different periods, which reflects the shear-wave velocity structure in the Fresnel volume of the propagating surface waves. Several studies have used dispersion measurements from ambient noise cross-correlations to investigate the shallow subsurface shear-wave velocity structure of active volcanoes around the world. Most use vertical components to retrieve the Rayleigh waves, but it is becoming increasingly common to use the horizontal seismogram components in addition to the vertical, giving further constraints to Rayleigh-wave measurements and introducing data relating to Love waves.  We compute 1,048,968 daily cross-correlations for 955 viable station pairs across the two periods, including all nine-components of the cross-correlation tensor where possible. These daily functions are then stacked into 7458 full-stacks, of which we make group velocity dispersion measurements for 2641 RR-, RZ-, TT-, ZR- and ZZ-component stacks. Cross-correlation quality varies across the networks, with some station pairs possibly contaminated with timing errors.  We observe both the fundamental and rst higher-order modes within our database of dispersion measurements. However, correctly identifying the mode of some measurements is challenging as the range of group velocities measured reflects both presence of multiple modes and heterogeneity of the local velocity structure. We assign modes to over 1900 measurements, of which we consider 1373 to be high quality.  We invert fundamental mode Rayleigh- and Love-wave dispersion curves independently and jointly for one dimensional shear-wave velocity profiles at Ruapehu and Tongariro Volcanoes, using dispersion measurements from two individual station pairs and average dispersion curves from measurements within specifi c areas on/around the volcanoes. Our Ruapehu profiles show little velocity variation with depth, suggesting that volcanic edifice is made of material that is compacting and being hydrothermally altered with depth. At Tongariro, we observe larger increases in velocity with depth, which we interpret as different layers within Tongariro's volcanic system. Slow shear-wave velocities, on the order of 1-2 km/s, are consistent with both P-wave velocities from existing velocity pro files of areas within the TgVC, and the observations of worldwide studies of shallow volcanic systems that used ambient noise cross-correlation.  A persistent observation across the majority of our dispersion measurements is that group velocities of the fundamental mode Love-wave group velocity measurements are slower than those of fundamental mode Rayleigh-waves, particularly in the frequency range of 0.25-1 Hz. Similarly, first higher-order mode Love-wave group velocities are slower than first higher-mode Rayleigh-wave velocities. This is inconsistent with the differences between synthetic dispersion curves that were calculated using isotropic, layered velocity models appropriate for Ruapehu and Tongariro. We think the Love-Rayleigh discrepancy is due to structures such as dykes or cracks in the vertical plane having greater influence than horizontal layering on surface-wave propagation. However, several measurements where Love-wave group velocities are faster than Rayleigh-wave group velocities suggests that in some places horizontal layering is the stronger influence.  We also observe that the differences between the Love- and Rayleigh-wave dispersion curves vary with the azimuth of the interstation path across Ruapehu and Tongariro Volcanoes. Some significant differences between Rayleigh-wave velocities of measurements with different interstation orientations are also observed, as are differences between Love-wave velocities. This suggests a component of azimuthal anisotropy within the volcanic structures, which coupled with the radial anistropy makes the shear-wave velocity structures of Ruapehu and Tongariro Volcanoes anisotropic with orthorhombic symmetry. We suggest that further work to determine three-dimensional structure should include provisions for anisotropy with orthorhombic or lower symmetry.</p>

Shear Wave Velocity Measurement in the Centrifuge Using Bender Elements

2014 ◽  
Vol 37 (4) ◽  
pp. 20130189 ◽  
Author(s):  
Waleed El-Sekelly ◽  
Anthony Tessari ◽  
Tarek Abdoun
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Velocity Measurement ◽  
Bender Elements

Determination of Shear Wave Velocity in the Soil by Dynamic Tests

2014 ◽  
Vol 969 ◽  
pp. 101-108
Author(s):  
Milan Sokol ◽  
Lenka Konecna
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Cross Correlation ◽  
Integration Method ◽  
Dynamic Tests ◽  
Dynamic Excitation ◽  
Recorded Data

This paper deals with determination of shear wave velocity in the soil directly in-situ by dynamic tests. Self-developed dynamic excitation impulse device was used in order to excite the soil during the tests. Consequently, accelerations of the soil vibration were measured by portable five-channel measurement equipment. Recorded data were evaluated by self-developed Square of Accelerations Integration Method, which was implemented to own created program VSANALYSIS. The same data were evaluated also by well known Method of Cross-Correlation Functions.

Characterization of Clay Sedimentation Using Piezoelectric Bender Elements

2006 ◽  
Vol 321-323 ◽  
pp. 1415-1420 ◽  
Author(s):  
Il Han Chang ◽  
Gye Chun Cho ◽  
Joo Gong Lee ◽  
Lee Hyung Kim
Keyword(s):  
Structure Formation ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soil Structure ◽  
Abrupt Change ◽  
Shear Waves ◽  
Measurement Techniques ◽  
The Self ◽  
Bender Elements

Sedimentation is one of the most basic processes in the formation of a soil structure in nature. Many studies have been performed to describe the characteristics of clay sedimentation, based on settlement and water content measurement. In addition, there have been some attempts in numerical modeling to describe soil structure formation as a whole. However, these effects still fall short in explaining the overall process of soil structure formation because some relevant properties are measured after a self-weight consolidation is completed. Furthermore some measurement techniques significantly alter soil structure. Thus, a non-destructive evaluation is necessary for the effective description of soil characteristics during the sedimentation process. In this study, a testing device is designed that continuously monitors the self-weight consolidation process of sedimentation with shear waves. Piezoelectric bender elements are installed into a testing cell to generate and receive shear waves in a small strain regime. Slurries are prepared with kaolinite-type clay and placed in the cell. Shear wave velocities are continuously measured as a function of time during the whole process of the self weight consolidation. The experimental results suggest that as clay sediment is subjected to a certain loading, the shear wave velocity increases as time increases, showing an abrupt change in log time. This abrupt change is relevant to the formation of a stable soil skeleton. It is concluded that the time-dependent variations in shear wave velocity reflect sedimentation and self weight consolidation behavior and the evolution of the effective stress increment.

Sign in / Sign up

Export Citation Format

Share Document