SHEAR WAVE VELOCITY BY TSP APPLIED BENDER ELEMENT TEST IN SAND

2006 ◽  
Vol 62 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Toshihiro OGINO ◽  
Hiroshi OIKAWA ◽  
Toshiyuki MITACHI ◽  
Masaki TSUSHIMA ◽  
Kohta NISHIDA
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Element ◽  
Bender Element Test

scholarly journals Shear modulus of hydrate bearing calcareous sand-fines mixture

2019 ◽  
Vol 92 ◽  
pp. 04002
Author(s):  
Litong Ji ◽  
Abraham C.F. Chiu ◽  
Lu Ma ◽  
Chao Jian
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Hydrate Formation ◽  
Confining Pressure ◽  
Specimen Preparation ◽  
Bender Element ◽  
Calcareous Sand ◽  
Bender Element Test

This article presents a laboratory study on the maximum shear modulus of a THF hydrate bearing calcareous sand (CS)–fines mixture. The maximum shear modulus was inferred from the shear wave velocity measured from the bender elements installed in a temperature-controlled triaxial apparatus. The specimen preparation procedures were specially designed to mimic the hydrate formation inside the internal pores of CS. A trial test was conducted to validate whether the shear wave velocity is a feasible parameter to monitor the formation and dissociation of hydrate in the CS-fines mixture. Based on the bender element test results, hydrate has a more profound effect than confining pressure on enhancing the maximum shear modulus of CS-fines mixture.

Application of the Non-Destructive Testing Method to Determine the Gmax of Bangkok Clay

2013 ◽  
Vol 418 ◽  
pp. 157-160 ◽  
Author(s):  
Keeratikan Piriyakul
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Field Test ◽  
Shear Wave Velocity ◽  
Non Destructive Testing ◽  
Bender Element ◽  
Destructive Testing ◽  
Testing Method ◽  
Bender Element Test ◽  
Non Destructive

This article presents the application of the non-destructive testing method (so called Bender element test) to measure the shear wave velocity and determine the maximum shear modulus of soft Bangkok clay samples. This research proposes the bender element technique to measure the shear wave velocity by means of piezoelectric ceramic sensors. The details of the bender element test were clearly explained. The laboratory bender element test data of the shear wave velocity were compared with the field test results and show that the field propagating waves pass along layers of higher stiffness while the laboratory test data were performed on small, possible less stiff material. The inversion calculation of the shear wave velocity in the field test is based on a linear elastic isotropic assumption which is not valid for the Bangkok subsoil and might be a second reason for the noticed differences in velocity.

Using Shear Wave Velocity to Assess the Stiffness of Soil-Cement-Fly Ash

2013 ◽  
Vol 459 ◽  
pp. 115-118
Author(s):  
Keeratikan Piriyakul
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Element ◽  
Cement Type ◽  
Soil Cement ◽  
Bender Element Test

This article presents the bender element technique to determine the stiffness of Bangkok clay mixed with the Portland cement type 1 and the fly ash type F by means of shear wave velocity. The Bangkok clay was mixed with 20% by weigh of Portland cement type 1 and varied the amount of fly ash (0, 10, 15, 20, 25 and 30% by weight). The soil-cement samples were cured for 3, 7, 14, 28 and 90 days. Then, these samples were performed the bender element test. The results reported that the optimum of replacement fly ash was about 15-20% and showed that the stiffness of soil-cement-fly ash mixing was increased with increasing the curing time. However, the shear wave velocity results were higher than the result of 0% replacement of fly ash which was the long term behaviour of cement mixed with fly ash.

scholarly journals Influence of Different Parameters on Shear Wave Velocity

2019 ◽  
Vol 8 (4) ◽  
pp. 9679-9684
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Confining Pressure ◽  
Bender Element ◽  
Damage Potential ◽  
Silt Content ◽  
Geological Conditions ◽  
Bender Element Test ◽  
Respective Field

Subsurface conditions play a major role in the damage potential of earthquakes. Local geological conditions generate significant amplification of the ground motion. The simple way to characterize the site condition is by estimating the shear wave velocity. The main objective of this paper is to evaluate the influence of silt content, density and confining pressure in the shear wave velocity. Soil samples were collected from different locations of College of Engineering, Guindy campus for conducting the bender element (BE) test. The shear wave velocity(Vs ) determined from bender element test for the respective field density were compared with shear wave velocity obtained from Multichannel Analysis of Surface Wave (MASW) test. For understanding the influence of above mentioned parameters the bender element tests were carried out. The important conclusions arrived through the studies are increase in density and confining pressure increases the shear wave velocity but increase in silt content decreases the shear wave velocity. The maximum variation in the shear wave velocity determined from laboratory and field are in the range of 11.62% to 18.5%.

Bender Element Test and Numerical Simulation of Sliding Zone Soil with Gravels of Huangtupo Landslide

2021 ◽  
Author(s):  
Yu Chen
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Wave Velocity ◽  
Small Strain ◽  
Testing System ◽  
Bender Element ◽  
Gravel Content ◽  
Consolidation Pressure ◽  
Bender Element Test ◽  
Sliding Zone

<p>In order to study the effect of the different consolidation pressure, loading-unloading path and gravel content on the shear modulus of the small strain of sliding zone soil, a set of consolidation bender element test device was developed. The device consists of three parts: a consolidation system, a deformation measuring system, and a shear wave testing system. The consolidation system is composed of a traditional consolidation instrument and the plexiglass cylinder box. The sample is cylindrical in shape and has a size of 50 mm×50 mm. The consolidation displacement is measured by a digital display micrometer. Shear wave testing system is a wave velocity measurement system made of piezoelectric ceramic. The experimental results show that the device can control the consolidation pressure and measure the vertical deformation, measure the shear wave velocity of the sliding zone soil in real-time, and then study the variation rule of the small strain shear modulus of the sliding zone soil with gravels. The shear modulus of the sliding zone soil increases with an increase in the consolidation pressure. The shear modulus of the unloading of sliding zone soil is larger than that of loading. Under the loading pressure of 200 kPa and 400 kPa, the shear modulus of the sliding zone soil first decreases and then increases with an increase in the gravel content. In the process of unloading, the shear modulus of the sliding zone soil increases with an increase in the gravel content. </p>

Automatic Shear Wave Velocity Estimation in Bender Element Testing

2016 ◽  
Vol 39 (4) ◽  
pp. 20140197 ◽  
Author(s):  
M. Finas ◽  
H. Ali ◽  
G. Cascante ◽  
P. Vanheeghe
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Velocity Estimation ◽  
Bender Element

Geogrid Stabilization of Unbound Aggregates Evaluated Through Bender Element Shear Wave Measurement in Repeated Load Triaxial Testing

2020 ◽  
Vol 2674 (3) ◽  
pp. 113-125
Author(s):  
Mingu Kang ◽  
Joon Han Kim ◽  
Issam I. A. Qamhia ◽  
Erol Tutumluer ◽  
Mark H. Wayne
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Resilient Modulus ◽  
Triaxial Tests ◽  
Triaxial Testing ◽  
Bender Element ◽  
Wave Measurement ◽  
Repeated Load ◽  
Repeated Load Triaxial

This paper describes the use of the bender element (BE) shear wave measurement technology for quantifying the effectiveness of geogrid stabilization of unbound aggregate materials with improved mechanical properties from repeated load triaxial testing. Crushed stone aggregate specimens were prepared with three different gradations, that is, upper bound (UB), mid-range engineered (ENG), and lower bound, according to the dense graded base course gradation specification in Illinois. The specimens were compacted at modified Proctor maximum dry densities and optimum moisture contents. Two geogrids with different triaxial aperture sizes were placed at specimen mid-height, and unstabilized specimens with no geogrid were also prepared for comparison. To measure shear wave velocity, three BE pairs were placed at different heights above geogrid. Repeated load triaxial tests were conducted following the AASHTO T307 standard resilient modulus test procedure, while shear wave velocity was measured from the installed BE pairs. After initial specimen conditioning, and at low, intermediate, and high applied stress states, both the resilient moduli and accumulated permanent strains were determined to relate to the geogrid local stiffening effects in the specimens quantified by the measured shear wave velocities. The resilient modulus and shear wave velocity trends exhibited a directly proportional relationship, whereas permanent strain and shear wave velocity values were inversely related. The enhancement ratios calculated for the geogrid stabilized over the unstabilized specimens showed significant improvements in mechanical behavior for the UB and ENG gradations, and a maximum enhancement was achieved for the engineered gradation specimens stabilized with the smaller aperture geogrid.

Dyadic wavelet analysis of bender element signals in determining shear wave velocity

2020 ◽  
Vol 57 (12) ◽  
pp. 2027-2030
Author(s):  
Guan Chen ◽  
Fang-Tong Wang ◽  
Dian-Qing Li ◽  
Yong Liu
Keyword(s):  
Wavelet Transform ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Near Field ◽  
Bender Element ◽  
Dyadic Wavelet ◽  
Wavelet Transform Modulus Maxima ◽  
Dyadic Wavelet Transform ◽  
Modulus Maxima

Determining shear wave velocity is a critical technique in bender element tests, as it can be readily affected by near-field effects, wave reflection, and other factors. This study proposes a new method based on the dyadic wavelet transform modulus maxima. Combining the local modulus maxima of dyadic wavelet transform approximate coefficients at fine decomposition levels and an appropriate threshold value, the proposed method can automatically detect the target point. For validation, a comparative study among the dyadic wavelet transform modulus maxima, peak-to-peak, first arrival, and cross-correlation methods was carried out using 140 sets of bender element signals. The comparison results show that the proposed method not only mitigates the adverse effects of near-field, later major peaks, and noise contamination, but is also more robust in estimating shear wave velocity.

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