Wave Velocity Change and Small-Strain Stiffness in Unsaturated Soils: Experimental Investigation

2012 ◽  
pp. 355-362 ◽  
Author(s):  
Milad Asslan ◽  
Frank Wuttke
Keyword(s):  
Experimental Investigation ◽  
Wave Velocity ◽  
Unsaturated Soils ◽  
Small Strain ◽  
Velocity Change ◽  
Small Strain Stiffness

scholarly journals Experimental Investigation on Small-Strain Stiffness of Marine Silty Sand

2020 ◽  
Vol 8 (5) ◽  
pp. 360 ◽  
Author(s):  
Qi Wu ◽  
Qingrui Lu ◽  
Qizhou Guo ◽  
Kai Zhao ◽  
Pen Chen ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Void Ratio ◽  
Reduction Rate ◽  
Confining Pressure ◽  
Small Strain ◽  
Silty Sand ◽  
Bender Element ◽  
Small Strain Stiffness ◽  
Alternative State ◽  
State Index

The significance of small-strain stiffness (Gmax) of saturated composite soils are still of great concern in practice, due to the complex influence of fines on soil fabric. This paper presents an experimental investigation conducted through comprehensive bender element tests on Gmax of marine silty sand. Special attention is paid to the influence of initial effective confining pressure ( σ c 0 ′ ), global void ratio (e) and fines content (FC) on Gmax of a marine silty sand. The results indicate that under otherwise similar conditions, Gmax decreases with decreasing e or FC, but decreases with increasing FC. In addition, the reduction rate of Gmax with e increasing is not sensitive to σ c 0 ′ , but obviously sensitive to changes in FC. The equivalent skeleton void ratio (e*) is introduced as an alternative state index for silty sand with various FC, based on the concept of binary packing material. Remarkably, the Hardin model is modified with the new state index e*, allowing unified characterization of Gmax values for silty sand with various FC, e, and σ c 0 ′ . Independent test data for different silty sand published in the literature calibrate the applicability of this proposed model.

Small-Strain Stiffness, Shear-Wave Velocity, and Soil Compressibility

2014 ◽  
Vol 140 (10) ◽  
pp. 06014011 ◽  
Author(s):  
Minsu Cha ◽  
J. Carlos Santamarina ◽  
Hak-Sung Kim ◽  
Gye-Chun Cho
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Small Strain ◽  
Small Strain Stiffness ◽  
Soil Compressibility

scholarly journals Small strain stiffness in overconsolidated Pliocene clays

2013 ◽  
Vol 45 (2) ◽  
pp. 169-181 ◽  
Author(s):  
Katarzyna Markowska-Lech ◽  
Mariusz Lech ◽  
Marek Bajda ◽  
Alojzy Szymański
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Cohesive Soil ◽  
Small Strain ◽  
Soil Parameters ◽  
Small Strain Stiffness ◽  
Triaxial Apparatus ◽  
Triaxial Cell

Abstract Small strain stiffness in overconsolidated Pliocene clays. A huge development of technical infrastructure, including the construction of many high-rise buildings, roads, railroads and extension of subway lines, took place over the recent years in Poland. Therefore, numerous planned investment projects require geotechnical data documenting the variation of soil parameters found in the subsoil. The shear wave velocity is one of the most important input parameters to represent the stiffness of the soil deposits. This paper focuses on the methods and devices using measurements of the shear wave velocity to estimate the initial shear modulus in cohesive soil. It is preferable to measure VS by in situ wave propagation tests, however it is often economically not feasible in all regions of Poland. Hence, a reliable correlation between shear wave velocity and parameters measured in triaxial cell or static penetration parameters would be a considerable advantage. This study shows results obtained from the bender elements tests and field techniques - seismic cone penetration test and seismic flat dilatometer, performed on overconsolidated cohesive soils in Warsaw. On the basis of the test results possible correlations between shear wave velocity (initial shear modulus), mean effective stress and void ratio are considered and four original empirical relationships are proposed. Moreover, the proposed formulas by two different techniques using triaxial apparatus and also RCPT cone were examined. The proposed formulas show a reasonable agreement with direct shear wave velocity profiles for clays and might be incorporated into routine laboratory and field practice

scholarly journals In situ shear wave velocity from multichannel analysis of surface waves (MASW) tests at eight Norwegian research sites

2007 ◽  
Vol 44 (5) ◽  
pp. 533-544 ◽  
Author(s):  
Michael Long ◽  
Shane Donohue
Keyword(s):  
Surface Waves ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Small Strain ◽  
Soft Clays ◽  
Small Strain Stiffness ◽  
Wave Measurements ◽  
Multichannel Analysis

The multichannel analysis of surface waves (MASW) technique, which is used to determine shear wave velocity (Vs) and hence small strain stiffness (Gmax), has recently generated considerable interest in the geophysics community. This is because of the ease of carrying out the test and analysis of the data. The objective of this work was to assess the repeatability, accuracy, and reliability of MASW surface wave measurements for use in engineering studies. Tests were carried out at eight well-characterized Norwegian clay, silt, and sand research sites where Vs had already been assessed using independent means. As well as being easy and quick to use, the MASW technique gave consistent and repeatable results, and the MASW Vs profiles for the clay sites were similar to those obtained from other techniques. Reasonable results were also obtained for the silt and sand sites, with the best result being obtained for the finer silt. This work also confirms that MASW Vs clay profiles are comparable to those obtained by correlation with cone penetration test (CPT) data. For these sites there also seems to be a good correlation between normalized small strain shear modulus and in situ void ratio or water content, and the data fit well with published correlations for clays.Key words: soft clays, silts, sands, small strain stiffness, shear wave velocity.

Recovery of Small-Strain Stiffness Following Blast-Induced Liquefaction Based on Shear Wave Velocity Measurements

2020 ◽  
Author(s):  
Siavash Mahvelati ◽  
Joseph Thomas Coe ◽  
Armin W. Stuedlein ◽  
Philip Asabere ◽  
Tygh Gianella ◽  
...  
Keyword(s):  
South Carolina ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Small Strain ◽  
Rate Variation ◽  
Time Rate ◽  
Small Strain Stiffness ◽  
Soil Fabric

Changes in soil fabric following liquefaction have been studied using various in-situ methods, and often return inconclusive or conflicting observations. The time-rate variation of stiffness, when observed, is usually not evaluated over significant periods of time, limiting investigations about aging in post-liquefaction regain of stiffness. Even more uncommon is the application of geophysical techniques to evaluate changes in shear wave velocity (VS) as a proxy for small-strain stiffness. This study uses controlled blasting to examine long-term post-liquefaction regain of stiffness following multiple blast events. The Multichannel Analysis of Surface Waves (MASW) technique was used to observe changes in VS of aged deposits at a test site in South Carolina. Blast-induced liquefaction of the target liquefiable layer resulted in significant reduction to its initial small-strain stiffness owing to the destruction of the aged soil fabric. The time-rate variation in VS indicated that the initial small-strain stiffness was not re-established over many months following liquefaction. Following a second blast event, the small-strain stiffness reduced again, but recovered more quickly, similar to previously reported observations of young sand deposits. This study provides a significant basis for interpreting in-situ body and surface wave measurements of aged and young sand deposits densified using blast liquefaction.

scholarly journals Estimation of the Small-Strain Stiffness of Clean and Silty Sands using Stress-Strain Curves and CPT Cone Resistance

2009 ◽  
Vol 49 (4) ◽  
pp. 545-556 ◽  
Author(s):  
Junhwan Lee ◽  
Doohyun Kyung ◽  
Bumjoo Kim ◽  
Monica Prezzi
Keyword(s):  
Small Strain ◽  
Stress Strain ◽  
Cone Resistance ◽  
Small Strain Stiffness
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