Shear-wave velocity and splitting within the Nankai accretionary prism off the Kii Peninsula: Insight into effective-stress and pore-pressure distribution

2009 ◽  
Author(s):  
Takeshi Tsuji ◽  
Gou Fujie ◽  
Ayako Nakanishi ◽  
Shuichi Kodaira ◽  
Toshifumi Matsuoka
Keyword(s):  
Pressure Distribution ◽  
Pore Pressure ◽  
Shear Wave ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Accretionary Prism ◽  
Kii Peninsula ◽  
Insight Into

scholarly journals Empirical relationships of shear wave velocity, SPT-N value and vertical effective stress for different soils in Mashhad, Iran

2015 ◽  
Vol 58 (3) ◽  
Author(s):  
Azam Ghazi ◽  
Naser Hafezi Moghadas ◽  
Hosein Sadeghi ◽  
Mohamad Ghafoori ◽  
Gholam Reza Lashkaripur
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Response Analysis ◽  
Empirical Relationships ◽  
Data Set ◽  
Fine Grain ◽  
Geophysical Investigations ◽  
Vertical Effective Stress

<p>Shear wave velocity, V<sub>s</sub>, is one of the important input parameters in seismic response analysis of the ground. Various methods have been examined to measure the soil V<sub>s</sub> directly. Direct measurement of V<sub>s</sub> is time consuming and costly, therefore many researchers have been trying to update empirical relationships between V<sub>s</sub> and other geotechnical properties of soils such as SPT Blow count, SPT-N. In this study the existence of a statistical relationship between V<sub>s</sub>, SPT-N<sub>60 </sub>and vertical effective stress, signa<sub>nu</sub>´, is investigated. Data set we used in this study was gathered from geotechnical and geophysical investigations reports. The data have been extracted from more than 130 numbers of geotechnical boreholes from different parts of Mashhad city. In each borehole the V<sub>s</sub> has been measured by downhole method at two meter intervals. The SPT test also has performed at the same depth. Finally relationships were developed by regression analysis for gravels, sands and fine grain soils. The proposed relationships indicate that V<sub>s</sub> is strongly dependent on signa<sub>nu</sub>´. In this paper the effect of fine percent also is considered on the V<sub>s</sub> estimation.</p>

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

Geophysics ◽  
1965 ◽  
Vol 30 (1) ◽  
pp. 117-121 ◽  
Author(s):  
B. S. Banthia ◽  
M. S. King ◽  
I. Fatt
Keyword(s):  
Hydrostatic Pressure ◽  
Pore Pressure ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Overburden Pressure ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
The Matrix ◽  
Internal Pore

Change in shear‐wave velocity for four dry sedimentary rocks has been studied as a function of the variation of both external hydrostatic pressure and internal pore pressure in the range 0 to 2,500 psi. The experimental method employs a beam of ultrasonic energy passing through a liquid in which a copper‐jacketed parallel‐sided slab of rock is rotated. The shear‐wave velocity is calculated from the laws of refraction and reflection of waves at a liquid‐solid boundary applied to the angle at which minimum energy is transmitted. The variation of shear‐wave velocity with pressure has been found to be a function of net overburden pressure, [Formula: see text], where [Formula: see text] hydrostatic pressure on the jacketed sample, [Formula: see text] pore pressure and n = a pressure‐dependent factor less than unity. The values of n at several differential pressures were chosen to yield a smooth curve passing through the displaced data points when the shear‐wave velocities were plotted as a function of net overburden pressure. Using the n values so obtained, the matrix compressibility [Formula: see text] for two of the sandstones has been calculated from the relation [Formula: see text]. The bulk compressibility [Formula: see text] for these two rocks had previously been obtained experimentally as a function of differential pressure. The values obtained for the matrix compressibility are in the range expected from a knowledge of the grain and cementing materials for these sandstones.

Shear wave velocity to evaluate in situ state of cohesionless soils

1995 ◽  
Vol 32 (5) ◽  
pp. 848-858 ◽  
Author(s):  
J.C. Cunning ◽  
P.K. Robertson ◽  
D.C. Sego
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Critical State ◽  
State Parameter ◽  
Worked Examples ◽  
Shear Loading ◽  
Cohesionless Soils

Shear wave velocity (Vs) measurements were carried out in a triaxial testing program on three different cohesionless soils. The Vs was measured using bender elements during consolidation and at ultimate steady state. After consolidation the soil samples were loaded in shear under constant strain rate triaxial compression either drained or undrained to determine their ultimate steady or critical state (USS) at large strains. The Vs measurements were used to develop relationships between the void ratio (e), mean normal effective stress (p′), and Vs. The shear loading results were expressed within the framework of critical state soil mechanics. The results of the Vs and USS information were combined with the state parameter concept to develop an equation to use field measured Vs to estimate the in situ consolidation state within a soil. Thus, the contractive–dilative boundary with respect to vertical effective stress for large strain loading can be determined from in situ measurements of Vs. These can then be used as a design aid to determine if a soil deposit is potentially susceptible to flow liquefaction. Worked examples to illustrate the procedure are given. Key words : shear wave velocity, cohesionless soil, in situ state, state parameter, liquefaction, laboratory testing.

scholarly journals Laboratory-Based Correlation between Liquefaction Resistance and Shear Wave Velocity of Sand with Fines

Geotechnics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 219-242
Author(s):  
Anthi I. Papadopoulou ◽  
Theodora M. Tika
Keyword(s):  
Shear Wave ◽  
Laboratory Investigation ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Test Results ◽  
Laboratory Studies ◽  
Bender Element ◽  
Liquefaction Resistance ◽  
Overburden Stress

This paper presents the results of a laboratory investigation into the effect of non-plastic fines on the correlation between liquefaction resistance and the shear wave velocity of sand. For this purpose, undrained stress-controlled cyclic triaxial and bender element tests were performed on clean sand and its mixtures with non-plastic silt. It is shown that the correlation between liquefaction resistance and shear wave velocity depends on fines content and confining effective stress. Based on the test results, correlation curves between field liquefaction resistance and overburden stress corrected shear wave velocity for sand containing various contents of fines are derived. These curves are compared to other previously proposed by field and laboratory studies.

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.

Correlation between shear wave velocity, void ratio and effective stress: Mapping Vs30 in Taiwan

2020 ◽  
Author(s):  
Jia Cian Gao ◽  
Jyun Liang Guo ◽  
Jia Jyun Dong ◽  
Chyi Tyi Lee
Keyword(s):  
Seismic Hazard ◽  
Shear Wave ◽  
Wave Velocity ◽  
Effective Stress ◽  
Shear Wave Velocity ◽  
Soil Profile ◽  
Void Ratio ◽  
Unit Weight ◽  
Hazard Evaluation ◽  
State Variables

&lt;p&gt;Site effect is one of the critical factors influencing the seismic hazard evaluation. Among others, the average shear-wave velocity of the upper 30 meters of a soil profile (Vs30) has been widely used for assessing the ground-motion amplification. However, spatial resolution of shear wave velocity data is usually poor for reginal- or national-wise evaluation. Standard Penetration Test N-value, the most abundant geotechnical data, was then used to estimate the shear wave velocity (Vs) empirically and the uncertainty of the Vs30 map can be reduced. In this study, we use the state variables of soils (void ratio and effective stress) to evaluate the shear wave velocity and to map the Vs30 in Taiwan. Engineering Geological Database for TSMIP (EGDT) comprises soil profile, shear wave velocity measurements, groundwater table, and soil physical properties (such as void ratio, water content, specific gravity, and unit weight), was used to construct the correlation between Vs, void ratio, and effective stress. The drilling database of Taiwan CGS was then used to estimate the spatial distribution of Vs30, where the Vs is un-available. The results were compared with the previous version of Vs30 map of Taiwan. The uncertainty of the new Vs30 map was evaluated and the propagation of uncertainty to the seismic hazard can be evaluated accordingly.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document