Estimating the undrained strength of sand: a theoretical framework

1995 ◽  
Vol 32 (5) ◽  
pp. 859-870 ◽  
Author(s):  
Catherine E. Fear ◽  
Peter K. Robertson
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Void Ratio ◽  
Triaxial Compression ◽  
State Parameter ◽  
In Situ Tests ◽  
Initial State ◽  
Undrained Strength

A framework for estimating the ultimate undrained steady state shear strength of sand (Su) from in situ tests, which combines the theory of critical state soil mechanics with shear wave velocity measurements, is presented. For a particular direction of undrained loading, samples of a given sand at a constant void ratio will reach the same Su, despite the magnitude of the initial effective confining stresses. Unique Su/p′ or [Formula: see text] ratios for a given direction of loading exist for a particular sand only if state parameter is constant throughout the deposit. Normalized shear wave velocity, Vs1, can be correlated with void ratio and is therefore used to estimate Su for a given initial state and direction of loading. Strengths in triaxial compression are examined in this paper; however, the same framework can be used to estimate strengths under other directions of loading. The Su–Vs1 relationship is shown to be relatively sensitive and should be used more as a screening tool rather than an accurate means of predicting Su. Vs1 is converted to equivalent values of SPT (N1)60 and CPT qc1, and the results are compared with the current methods of estimating Su. Key words : in situ testing, liquefaction, sand, undrained strength.

Development of global correlation models between in situ stress-normalized shear wave velocity and soil unit weight for plastic soils

2016 ◽  
Vol 53 (10) ◽  
pp. 1600-1611 ◽  
Author(s):  
Sung-Woo Moon ◽  
Taeseo Ku
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Void Ratio ◽  
Unit Weight ◽  
Model Parameters ◽  
Site Specific ◽  
Global Correlation ◽  
Soil Unit

Shear wave velocity (Vs) in geo-materials is strongly dependent on factors such as stress state, void ratio, and soil structure. Stress-dependency and void-ratio dependency can be represented by the equations [Formula: see text] and Vs = a(e)b (where α and a are material constants; exponents β and b represent the sensitivity of stress and the void dependent effect, respectively; [Formula: see text] is effective confining stress; e is void ratio), respectively. To consider the effect of soil disturbance and stress relief in geo-materials, shear wave velocity is often required to be normalized by adopting the site-specific model parameters (β or b). Based on a special in situ database compiled from 156 well-documented test sites that include various geo-materials, this study presents (i) the apparent relationships of the model parameters α and β for all soil and rock materials as well as a and b for all soil materials, (ii) new global correlations between soil unit weight and two types of stress-normalized shear wave velocities (Vs1 and Vsn), instead of the conventional Vs – soil unit weight relationship for clays, and (iii) the best-fitted multi-regression models between soil unit weight and site-specifically normalized shear wave velocity as well as the plasticity index for plastic soils. Moreover, this study presents the importance of site-specific stress normalization (Vsn) in creating a better correlation model. The proposed relationships offer first-order assessments of soil unit weight within the ranges of available data, which are also approximately guided by a hyperbolic unit weight model with depth.

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.

Interpretation of in situ test results from the CANLEX sites

2000 ◽  
Vol 37 (3) ◽  
pp. 505-529 ◽  
Author(s):  
C E (Fear) Wride ◽  
P K Robertson ◽  
K W Biggar ◽  
R G Campanella ◽  
B A Hofmann ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soil Liquefaction ◽  
In Situ Testing ◽  
Cone Penetration ◽  
In Situ Tests ◽  
Cone Penetration Tests ◽  
Penetration Tests

One of the primary objectives of the Canadian Liquefaction Experiment (CANLEX) project was to evaluate in situ testing techniques and existing interpretation methods as part of the overall goal to focus and coordinate Canadian geotechnical expertise on the topic of soil liquefaction. Six sites were selected by the CANLEX project in an attempt to characterize various deposits of loose sandy soil. The sites consisted of a variety of soil deposits, including hydraulically placed sand deposits associated with the oil sands industry, natural sand deposits in the Fraser River Delta, and hydraulically placed sand deposits associated with the hard-rock mining industry. At each site, a target zone was selected and various in situ tests were performed. These included standard penetration tests, cone penetration tests, seismic downhole cone penetration tests (giving shear wave velocity measurements), geophysical (gamma-gamma) logging, and pressuremeter testing. This paper describes the techniques used in the in situ testing program at each site and presents a summary and interpretation of the results.Key words: CANLEX, in situ testing, shear wave velocity, geophysical logging, pressuremeter.

In Situ Shear Wave Velocity From Multichannel Analysis of Surface Waves (MASW) Tests at Six Sites of Delhi Technological University

2020 ◽  
Author(s):  
Rajat Gautam ◽  
A.K. Srivastava Srivastava ◽  
Shubham Gupta ◽  
Vishal Sharma
Keyword(s):  
Surface Waves ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Multichannel Analysis ◽  
Technological University

Soil Liquefaction Evaluation of Offshore Site Based on In Situ Shear Wave Velocity Measurements

2013 ◽  
Vol 405-408 ◽  
pp. 470-473
Author(s):  
Sheng Jie Di ◽  
Ming Yuan Wang ◽  
Zhi Gang Shan ◽  
Hai Bo Jia
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Wind Farm ◽  
Soil Liquefaction ◽  
Offshore Wind ◽  
Velocity Measurements ◽  
Liquefaction Resistance ◽  
Liquefaction Potential

A procedure for evaluating liquefaction resistance of soils based on the shear wave velocity measurements is outlined in the paper. The procedure follows the general formal of the Seed-Idriss simplified procedure. In addition, it was developed following suggestions from industry, researchers, and practitioners. The procedure correctly predicts moderate to high liquefaction potential for over 95% of the liquefaction case histories. The case study for the site of offshore wind farm in Jiangsu province is provided to illustrate the application of the proposed procedure. The feature of the soils and the shear wave velocity in-situ tested in site are discussed and the liquefaction potential of the layer is evaluated. The application shows that the layers of the non-cohesive soils in the depths 3-11m may be liquefiable according to the procedure.

scholarly journals Shear wave velocity jump at the olivine-spinel transformation in Fe2SiO4 by ultrasonic measurements in situ.

1982 ◽  
Vol 30 (3) ◽  
pp. 245-253 ◽  
Author(s):  
Akira FUKIZAWA ◽  
Hajimu KINOSHITA
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Ultrasonic Measurements ◽  
Velocity Jump

scholarly journals CHARACTERIZING A TROPICAL SOIL VIA SEISMIC IN SITU TESTS

2019 ◽  
Vol 37 (3) ◽  
pp. 263
Author(s):  
Breno Padovezi Rocha ◽  
Heraldo Luiz Giacheti
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Soil Profile ◽  
Site Investigation ◽  
Tropical Soil ◽  
Engineering Properties ◽  
Foundation Engineering

ABSTRACT. The shear wave velocity (Vs) is an important geotechnical parameter to be used in dynamic problems (e.g. earthquakes and vibration problems) as well as in static deformation analysis such as excavations and foundation engineering design. There are several in situ seismic tests to determine Vs such as the crosshole and the downhole techniques, as well as hybrid tests (e.g. seismic dilatometer – SDMT). This paper presents crosshole, downhole and SDMT tests carried out in a typical tropical soil profile from Brazil. Advantages and limitations regarding the test procedures and interpretation are briefly presented and differences observed among Vs determined by these techniques are discussed. Shear wave velocities (Vs) estimated from the crosshole, downhole and SDMT tests ranging from 194 to 370 m/s. The shear wave velocity suggests that the experimental site could be divided into two strata, which are in agreement with soil profile description. The maximum shear modulus (G0) calculated from the Vs by theory of elasticity can be used to show the investigated tropical soil is a typical unusual geomaterial. This article also emphasizes that the SDMT is a useful test for site investigation since it allows a great means for profiling geostratigraphy and soil engineering properties during routine site investigation as well as for dynamics problems. Keywords: shear wave velocity, maximum shear modulus, crosshole, downhole, SDMT.RESUMO. A velocidade de onda cisalhante (Vs) é um parâmetro geotécnico empregado em análises dinâmicas (terremotos e problemas de vibração), bem como em análises estáticas (escavações e projeto de fundações). Existem vários ensaios sísmicos de campo para a determinação de Vs, entre eles as técnicas crosshole e downhole, e os ensaios híbridos (por exemplo, dilatômetro sísmico – SDMT). Este artigo apresenta os ensaios crosshole, downhole e SDMT realizados em um perfil típico de solo tropical do Brasil, as vantagens e limitações dos procedimentos de ensaio e de interpretação são brevemente apresentadas, e as diferenças observadas entre os valores de Vs determinados pelas diferentes técnicas são discutidas. Os perfis de Vs determinados pelas diferentes técnicas variaram de 194 a 370 m/s. A velocidade da onda cisalhante sugere que o campo experimental investigado pode ser dividido em dois horizontes, os quais estão de acordo com a descrição do perfil do solo estudado. O módulo de cisalhamento máximo (G0), calculado a partir de Vs pela teoria da elasticidade, pode ser utilizado para demonstrar o comportamento não convencional do solo investigado. Este artigo também enfatiza que o SDMT é um ensaio geotécnico útil para a investigação geotécnica do subsolo, uma vez que permite a definição do perfil estratigráfico e a estimativa de parâmetros estáticos e dinâmicos de um projeto.Palavras-chave: velocidade de onda cisalhante, módulo de cisalhamento máximo, crosshole, downhole, SDMT.

Critical Insights in Laboratory Shear Wave Velocity Correlations of Clays

2021 ◽  
Author(s):  
Dania Elbeggo ◽  
Yannic Ethier ◽  
Jean-Sébastien Dubé ◽  
Mourad Karray
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Earth Pressure ◽  
Dynamic Parameter ◽  
Clay Deposits ◽  
Sample Disturbance ◽  
P Rat

Shear wave velocity is an important mechanical/dynamic parameter allowing the characterization of a soil in the elastic range (γ < 0.001 %). Thirty five existing laboratory correlations of small strains shear modulus or shear wave velocity were examined in this study and are grouped into different general forms based on their geotechnical properties. A database of 11 eastern Canadian clay deposits was selected and used for the critical insights. The effect of the coefficient of earth pressure at rest was also examined. A range of variation for each general form of correlation was determined to take the plasticity index and void ratio values of investigated sites into account. The analysis shows a significant scatter in normalized shear wave velocity values predicted by existing correlations and raises questions on the applicability of these correlations, especially for eastern Canadian clays. New correlations are proposed for Champlain clays based on laboratory measurement of shear wave velocity using the piezoelectric ring actuator technique, P-RAT, incorporated in consolidation cells. An analysis of P-RAT results reveals the sample disturbance effect and suggests an approach to correct the effect of disturbance on laboratory shear wave velocity measurements. The applicability of the proposed correlations, including the disturbance correction, is validated by comparison with in situ measurements using multi-modal analysis of surface waves (MMASW).

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