scholarly journals Investigation on Shear Wave Velocity and Triaxial Mechanical Performance of Tailings Core from Tailings Dam

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Pengfei Luo
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Static Pressure ◽  
Pressure Coefficient ◽  
Confining Pressure ◽  
Quantitative Relation ◽  
Exponential Fitting ◽  
Peak Strain ◽  
The Stability

The physical and mechanical parameters of tailings are important to study the stability of tailings dams (TDs). In this study, a series of laboratory experiments (shear wave velocity, triaxial compressive, and peak strain strength testing) were conducted to obtain the mechanical properties of tailings from TD. The results showed the following. (1) The linear function fitting could characterize the quantitative relationship between shear wave velocity and hole depth. (2) The corresponding static pressure coefficient increased as the confining pressure increased. The exponential fitting could characterize the quantitative function relation between the static pressure coefficient and the confining pressure. (3) The cohesion and internal friction angle of the tailings sample were 20 kPa and 41°, respectively, and the logarithmic fitting could better characterize the quantitative relation between shear peak strength and confining pressure. The results of this study can provide important references for further research on the stability of TD.

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.

Shear wave velocity as a geotechnical parameter: an overview

2016 ◽  
Vol 53 (2) ◽  
pp. 252-272 ◽  
Author(s):  
Mahmoud N. Hussien ◽  
Mourad Karray
Keyword(s):  
Grain Size ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Field Measurements ◽  
Confining Pressure ◽  
Standard Penetration Test ◽  
Substantial Impact ◽  
Available N ◽  
Tip Resistance

Shear wave velocity, Vs, is a soil mechanical property that can be advantageously measured in both the field and laboratory under real and controlled conditions. The measured Vs values are customarily used in conjunction with other in situ (e.g., standard penetration test blow count, N-SPT, and cone penetration resistance, qc-CPT) and laboratory (e.g., effective confining pressure, [Formula: see text], and void ratio, e) measurements to establish an abundant number of Vs-based correlations that could later be utilized to augment (in some cases, replace) designated testing. An attempt is made here to present the salient features of some existing widely used correlations to provide the reader with a comprehensive understanding about the nature of these correlations and their applicability in geotechnical engineering practices. It is recognized that the reliability of some of these empirical formulations, still in general use today, has been questioned, as they are characterized by their lack of dependence on stress state and particle characteristics. A new Vs1–(N1)60 (where Vs1 is the stress-normalized shear wave velocity, and (N1)60 is the stress-normalized penetration blow count) correlation that accounts for grain sizes is highlighted by combining a recently published Vs1–qc1 (where qc1 is the stress-normalized cone tip resistance) formulation and available (N1)60–qc1 relationships. The new formulation is applicable to uncemented relatively young Holocene-age soil deposits. The estimated Vs1 values based on the proposed correlation are compared with reliable laboratory and field measurements, and the comparison shows that accounting for grain size of granular soils yields more realistic results regarding the Vs values than when particle size is not considered. The prime effect of grain size was to change the range of possible void ratios, which in turn had a substantial impact on Vs values. Moreover, a new Vs1–(N1)60 chart has been proposed, allowing the practitioner to estimate Vs1 values based on a combination of data including N-SPT, e, grain size, and relative density.

scholarly journals Correlation between shear wave velocity and effective confining pressure using cyclic triaxial testing apparatus

2019 ◽  
Vol 92 ◽  
pp. 04009
Author(s):  
Guojun Liu ◽  
Noriyuki Yasufuku ◽  
Ryohei Ishikura ◽  
Qiang Liu
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Confining Pressure ◽  
Similar Rate ◽  
Bender Elements ◽  
Confining Stress ◽  
Liquefaction Resistance ◽  
Ground Shaking

The 2016 Kumamoto earthquakes struck Kumamoto and Ōita regions and caused several devastating liquefaction induced damages. The primary damage was due to the extreme ground shaking of the foreshock and main shock sequence. Therefore, it is essential to develop a quick reliable approach with a high accuracy to assess the ground situation after foreshock or several shocks. Velocity of small shear wave (Vs) was widely used for evaluating the potential liquefaction. This study investigates the possibility of using Vs as a new indicator of the stress state in the soil after earthquake and evaluation of post liquefaction resistance of soil. Cyclic tri-axial apparatus equipped with bender elements were used to conduct two consecutives liquefaction tests on sandy soil. The Vs measured by bender elements was discussed on the relationship with effective stress during the liquefying processes. The results showed that for the sandy soils, a) Vs could not clearly reflect the significant reduction in resistance at re-liquefaction stages by directly comparing the Vs at the end of consolidation between first and stages, b) The shear wave velocity is significantly affected by effective confining pressure c) the shear wave velocity of 190 m/s was at confining pressure of 100 kPa. The shear wave velocity reaches to after 100 m/s after consolidations and re-consolidations. The shear wave velocity was found to reduce to 100 m/s when the effective confining stress reaches to 0 and to around 25 m/s when the double amplitude reaches to 5%; d) the velocity and effective stress decreases with a similar rate in liquefying process.

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%.

scholarly journals Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Yaniv Darvasi ◽  
Amotz Agnon
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Dead Sea ◽  
Attenuation Curve ◽  
Surface Wave Dispersion ◽  
Near Surface ◽  
Moderate Seismicity ◽  
Local Point ◽  
The Dead

Abstract. Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150 km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60 % of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.

scholarly journals Multi-method site characterization to verify the hard rock (Site Class A) assumption at 25 seismograph stations across Eastern Canada

2021 ◽  
pp. 875529302110010
Author(s):  
Sameer Ladak ◽  
Sheri Molnar ◽  
Samantha Palmer
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Hard Rock ◽  
Site Characterization ◽  
Eastern Canada ◽  
Site Class ◽  
Paleozoic Rock ◽  
Rock Types ◽  
Site Period

Site characterization is a crucial component in assessing seismic hazard, typically involving in situ shear-wave velocity ( VS) depth profiling, and measurement of site amplification including site period. Noninvasive methods are ideal for soil sites and become challenging in terms of field logistics and interpretation in more complex geologic settings including rock sites. Multiple noninvasive active- and passive-seismic techniques are applied at 25 seismograph stations across Eastern Canada. It is typically assumed that these stations are installed on hard rock. We investigate which site characterization methods are suitable at rock sites as well as confirm the hard rock assumption by providing VS profiles. Active-source compression-wave refraction and surface wave array techniques consistently provide velocity measurements at rock sites; passive-source array testing is less consistent but it is our most suitable method in constraining the rock VS. Bayesian inversion of Rayleigh wave dispersion curves provides quantitative uncertainty in the rock VS. We succeed in estimating rock VS at 16 stations, with constrained rock VS estimates at 7 stations that are consistent with previous estimates for Precambrian and Paleozoic rock types. The National Building Code of Canada uses solely the time-averaged shear-wave velocity of the upper 30 m ( VS30) to classify rock sites. We determine a mean VS30 of ∼ 1600 m/s for 16 Eastern Canada stations; the hard rock assumption is correct (>1500 m/s) but not as hard as often assumed (∼2000 m/s). Mean variability in VS30 is ∼400 m/s and can lead to softer rock classifications, in particular, for Paleozoic rock types with lower average rock VS near the hard/soft rock boundary. Microtremor and earthquake horizontal-to-vertical spectral ratios are obtained and provide site period classifications as an alternative to VS30.

scholarly journals The Polito Surface Wave flat-file Database (PSWD): statistical properties of test results and some inter-method comparisons

2021 ◽  
Vol 19 (6) ◽  
pp. 2343-2370
Author(s):  
Federico Passeri ◽  
Cesare Comina ◽  
Sebastiano Foti ◽  
Laura Valentina Socco
Keyword(s):  
Surface Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Active Surface ◽  
Statistical Properties ◽  
Test Results ◽  
Flat File ◽  
Research Fields ◽  
Database Content

AbstractThe compilation and maintenance of experimental databases are of crucial importance in all research fields, allowing for researchers to develop and test new methodologies. In this work, we present a flat-file database of experimental dispersion curves and shear wave velocity profiles, mainly from active surface wave testing, but including also data from passive surface wave testing and invasive methods. The Polito Surface Wave flat-file Database (PSWD) is a gathering of experimental measurements collected within the past 25 years at different Italian sites. Discussion on the database content is reported in this paper to evaluate some statistical properties of surface wave test results. Comparisons with other methods for shear wave velocity measurements are also considered. The main novelty of this work is the homogeneity of the PSWD in terms of processing and interpretation methods. A common processing strategy and a new inversion approach were applied to all the data in the PSWD to guarantee consistency. The PSWD can be useful for further correlation studies and is made available as a reference benchmark for the validation and verification of novel interpretation procedures by other researchers.

Sign in / Sign up

Export Citation Format

Share Document