Evaluation of overburden stress effects on liquefaction resistance at Duncan Dam

2012 ◽  
Vol 49 (9) ◽  
pp. 1052-1058 ◽  
Author(s):  
Ross W. Boulanger ◽  
I.M. Idriss
Keyword(s):  
Standard Penetration Test ◽  
Triaxial Testing ◽  
Penetration Test ◽  
Liquefaction Resistance ◽  
Stress Effects ◽  
Cyclic Resistance ◽  
Evaluation Procedures ◽  
Direct Simple Shear ◽  
Overburden Stress

The cyclic resistance of sand unit 3c at Duncan Dam in British Columbia for overburden stresses of about 2 to 12 atm (1 atm = 101.325 kPa) was evaluated previously using cyclic undrained direct simple shear (DSS) and cyclic undrained triaxial testing of samples obtained using frozen sampling techniques. The in situ standard penetration test (SPT) and laboratory testing results provide a unique set of data for evaluating how the effects of effective overburden stress are accounted for in liquefaction evaluation procedures. The present study re-examines the cyclic resistance of these sands based on the field and laboratory test data for the unit 3c sands underlying Duncan Dam relative to the site-specific procedures developed by Pillai and Byrne and the liquefaction triggering evaluation procedures presented by Idriss and Boulanger, Youd et al., and Cetin et al. The differences in the results and the reasons for the differences are discussed.

A laboratory investigation of the dynamic properties of tailings

2011 ◽  
Vol 48 (11) ◽  
pp. 1587-1600 ◽  
Author(s):  
Michael James ◽  
Michel Aubertin ◽  
Dharma Wijewickreme ◽  
G. Ward Wilson
Keyword(s):  
Dynamic Properties ◽  
Cyclic Stress ◽  
Test Results ◽  
Liquefaction Resistance ◽  
Cyclic Stress Ratio ◽  
Cyclic Resistance ◽  
Direct Simple Shear ◽  
Cyclic Resistance Ratio ◽  
Modulus Reduction

The dynamic response of tailings from a gold mine located in western Quebec was evaluated using cyclic laboratory testing. These tailings are classified as nonplastic silt and sand. Specimens of the tailings were prepared as slurries, consolidated to vertical effective stresses of 100–400 kPa, and subjected to cyclic direct simple shear testing with cyclic stress ratio, CSR, values between 0.075 and 0.15. The shear modulus reduction of the tailings under cyclic loading was found to be fairly similar to that described for clean sands in the literature. The cyclic resistance ratio, CRR (which reflects the liquefaction resistance), of the samples was not significantly affected by the effective consolidation stress (in the range considered here). Analysis of test results with the simplified method of liquefaction evaluation indicates that this method may be applicable to these tailings. However, other factors, such as the possible effects of layering and ageing of the tailings in situ, should also be considered in such an assessment.

In Situ Investigation of Liquefiable Gravels

2000 ◽  
Vol 1714 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Joseph P. Koester ◽  
Chris Daniel ◽  
Michael L. Anderson
Keyword(s):  
Standard Penetration Test ◽  
Lateral Spreading ◽  
Test Results ◽  
Penetration Test ◽  
Liquefaction Resistance ◽  
Testing Procedures ◽  
In Situ Investigation ◽  
Penetration Tests

A series of dynamic in situ penetration tests was performed in deep alluvial gravel deposits at Seward, Alaska, that were shaken and apparently liquefied by the March 27, 1964, Alaska earthquake. Both a U.S. standard penetration test split spoon and a larger-diameter drive sampler were used, and dynamic cone penetrometers of two sizes were also driven into the gravels near the mouth of the Resurrection River that had exhibited settlement and lateral spreading as a result of earthquake shaking. Two safety hammers were used [nominally 623 N (140 lb) and 1334 N (300 lb)], and the energy delivered with various hammer and penetrometer combinations was measured throughout all tests. Limited measurements of hammer velocity were also made by a radar system developed for that purpose to allow for kinetic energy determination. Soils recovered in the split spoon samplers were sent to the U.S. Army Engineer Waterways Experiment Station Soils Research Facility in Vicksburg, Mississippi, where they were evaluated for classification (gradation and index properties). The sampling and testing procedures used at the Seward site, as well as preliminary analysis of the various penetration test results, are summarized. Comparisons are made with penetration resistance measurements made by the Alaska Highway Department immediately after the 1964 earthquake. Results of this investigation will be adapted to guide future practice for in situ determination of liquefaction resistance in coarse alluvial soils.

Assessment of the range of variation of Nγ from 60 estimation methods for footings on sand

2013 ◽  
Vol 50 (7) ◽  
pp. 793-800 ◽  
Author(s):  
Edgar Giovanny Diaz-Segura
Keyword(s):  
Friction Angle ◽  
Standard Penetration Test ◽  
Estimation Methods ◽  
Penetration Test ◽  
In Situ Tests ◽  
Vertical Loading ◽  
Simplified Method ◽  
Bearing Capacity Factor ◽  
Range Of Variation

The range of variation of the bearing capacity factor, Nγ, was assessed using 60 estimation methods for rough footings on sand subjected to static vertical loading. The influence on the Nγ values of the use of correlations for the estimation of the friction angle, [Formula: see text], derived from in situ tests was also assessed. The analysis shows a marked dependency on the methods used to determine Nγ, showing differences for the same [Formula: see text] values of up to 267% between estimated values. Uncertainty in the estimation of [Formula: see text], due to the use of correlations with in situ tests, leads to a range of variation for Nγ higher than that seen using the 60 estimation methods. Finally, given the regular use of the in situ standard penetration test (SPT) on sands, and based on a series of analyses using finite elements, a simplified method in terms of the SPT N-values is proposed for estimation of Nγ in footings on sands.

scholarly journals PROPOSTA DE APLICAÇÃO DE RESULTADOS DE SONDAGENS COM MARTELO LEVE (DPL) NO CAMPO EXPERIMENTAL DA UNIFOR EM PROJETOS DE FUNDAÇÕES PARA PEQUENAS CARGAS [ Proposal for the Application of Dynamic Probing Light (DPL) Results in the Experimental Field of UNIFOR in Foundations Projects for Small Loads ]

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Marcos Fábio Porto de Aguiar ◽  
Fernando Feitosa Monteiro ◽  
Francisco Heber Lacerda de Oliveira ◽  
Yago Machado Pereira de Matos
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Coefficient Of Determination ◽  
Deep Foundations ◽  
Penetration Test ◽  
In Situ Tests ◽  
Foundation Design ◽  
Experimental Field

RESUMO: Em meio aos diversos métodos utilizados no Brasil para determinação da capacidade de carga de fundações, a grande maioria parte do índice de resistência à penetração (NSPT). Para o caso de pequenas edificações, devido a fatores geralmente econômicos, a experiência ou a prática regional costumam prevalecer. Sendo assim, são elaborados, muitas vezes, projetos sem um procedimento de cálculo fundamentado em parâmetros comprovados por ensaios geotécnicos, podendo ocasionar problemas na edificação, como recalques excessivos, ou, até mesmo, comprometer a segurança da estrutura. Dessa forma, técnicas mais simples e de baixo custo, como o DPL (Dynamic Probing Light), podem ser uma opção para situações de pequenas cargas, viabilizando projetos fundamentados em ensaios in situ. Partindo de investigações com o DPL, este trabalho tem o objetivo de dimensionar fundações superficiais e profundas para edificações de pequeno porte através de algumas das principais metodologias disponíveis na literatura e verificar a sua eficiência. Por meio de resultados de campanhas de sondagens SPT (Standard Penetration Test) e DPL no campo experimental da Universidade de Fortaleza (UNIFOR), determinou-se a capacidade de carga de fundações superficiais e profundas fazendo aplicação dos índices NSPT e NSPT equivalente obtido pela correlação com o DPL. Identificou-se que essa correlação apresentou coeficiente de determinação satisfatório entre os parâmetros obtidos nos ensaios SPT e DPL para o terreno em questão, mostrando-se o DPL ser uma alternativa pertinente, em termos técnicos para projetos de fundações de obras de pequeno porte.ABSTRACT: Among the various methods used in Brazil of the determination of the bearing capacity on foundations, most part uses the standard penetration resistance (NSPT). For small constructions, due to economic factors generally, experience or regional practice usually prevails. Thus, projects without a reasoned calculation procedure in parameters supported by geotechnical tests are often designed, and may cause problems in the building, as excessive settlements, or even compromise the safety of the structure. In this way, simple and low cost techniques such as DPL (Dynamic Probing Light) may be an option for small loads situations, enabling projects based on in situ tests. This paper proposes to calculate the dimensions of shallow and deep foundations for small constructions and check its efficiency using DPL tests. Through the results of SPT (Standard Penetration Test) and DPL tests in the experimental field of the University of Fortaleza (UNIFOR), the determination of the bearing capacity in shallow and deep foundations was done using NSPT index and equivalent NSPT index obtained by the correlation with DPL. A correlation with satisfactory coefficient of determination was obtained between SPT and DPL tests parameters for the analyzed field, showing up the DPL as an appropriate alternative in technical terms for foundation design of small constructions.

scholarly journals ANALISIS POTENSI CYCLIC MOBILITY PADA TANAH KOHESIF

2019 ◽  
Vol 2 (3) ◽  
pp. 77
Author(s):  
Nicky Fernando ◽  
Aniek Prihatiningsih
Keyword(s):  
Axial Strain ◽  
Cyclic Strain ◽  
Standard Penetration Test ◽  
Cyclic Stress ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cyclic Stress Ratio ◽  
Cyclic Mobility ◽  
Cyclic Resistance ◽  
Cyclic Resistance Ratio

Likuifaksi merupakan fenomena dimana kekuatan tahanan tanah berkurang karena meningkatnya tegangan air pori saat gempa bumi berlangsung. Likuifaksi dibagi menjadi dua tipe berdasarkan proses kejadiannya yaitu flow liquefaction dan cyclic mobility. Hal pertama dalam analisis potensi likuifaksi adalah pemeriksaan kerentanan likuifaksi dari karakteristik tanah. Pemeriksaan kerentanan menggunakan empat metode yaitu Chinese criteria, metode Seed et al. dan metode Bray dan Sancio. Jika tanah menunjukan rentan terhadap likuifaksi, perhitungan evaluasi dapat dilanjutkan jika tidak maka perhitungan tidak dilanjutkan. Setelah menentukan kerentanan, tanah yang rentan likuifaksi akan ditentukan tipe likuifaksi menggunakan state criteria. Penentuan tipe likuifaksi dapat dilihat dari grafik hubungan deviatoric stress (q), mean effective stress (p’) dan axial strain (εa). Evaluasi potensi likuifaksi menggunakan metode cyclic strain approach. Metode ini menggunakan dua variabel yaitu cyclic stress ratio (CSR) dan cyclic resistance ratio (CRR) yang dapat ditentukan dari data tes lapangan untuk menentukan potensi likuifaksi setiap lapisan tanah. Tes lapangan yang digunakan adalah standard penetration test (SPT) dan cone penetration test (CPT). Penelitian ini menganalisa potensi cyclic mobility pada tanah kohesif serta faktor keamanan. Hasil dari penelitian ini menunjukan bahwa tipe likuifaksi yang terjadi adalah cyclic mobility dan adanya potensi likuifaksi pada tanah kohesif.

scholarly journals ANÁLISE DE PERFIS DE SONDAGEM SPT E CARACTERIZAÇÃO GEOTÉCNICA DE SOLOS DO MUNICÍPIO DE NATAL

2007 ◽  
Vol 1 ◽  
pp. 38
Author(s):  
Kadson Ranniere da Rocha Câmara ◽  
Alexandre da Costa Pereira
Keyword(s):  
Standard Penetration Test ◽  
Penetration Test

O presente trabalho tem como objetivo a caracterização geotécnica de solos do município de Natal para fins de obtenção de parâmetros de resistência ao cisalhamento e de deformabilidade do material. Quatro zonas foram definidas para a compilação de resultados de relatórios de sondagens tipo SPT (Standard Penetration Test), buscando-se destacar aspectos que diferenciem geotecnicamente as zonas consideradas. Campanhas de ensaios de laboratório foram relizadas para a idendificação de características geotécnicas (perfil de umidades e granulometria, densidade das partículas e deformabilidade) de solo definido como referência para as análises. Parâmetros de resistência ao cisalhamento e de deformabilidade dos solos encontrados foram determinados mediante emprego de equações empíricas. Os resultados encontrados indicam haver importante variabilidade nas propriedades geotécnicas dos solos analisados, tanto para solos pertencentes a uma mesma zona como para solos de zonas distintas. O posicionamento das unidades geotécnicas e o estado de compacidade das mesmas consistem em variáveis destacadas no estudo realizado. Palavras-chaves: Mecânica dos Solos; Ensaios In Situ; Perfis SPT; Caracterização Geotécnica.

scholarly journals Selection of Standard Penetration Test Number for Geotechnical Investigation of a Vertical Cross-section Considering Spatial Variability and Correlation in Soil Properties

2021 ◽  
Author(s):  
Zheng Guan ◽  
Yu Wang
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Cross Section ◽  
Site Investigation ◽  
Standard Penetration Test ◽  
Vertical Cross Section ◽  
Penetration Test ◽  
Geotechnical Design ◽  
Selection Of

Standard Penetration test (SPT) is a widely used in-situ test for characterizing variation of subsurface soil properties, and results of site investigation are usually simplified as a 2D vertical cross-section for subsequent geotechnical design and construction. Current geotechnical design codes and guidelines only provide general recommendations for selection of an appropriate number of in-situ tests (e.g., SPT) (e.g., the greater variability of subsurface conditions, the larger number of SPTs required to obtain sufficient underground information). No quantitative or rational method is available for selecting the appropriate number of SPTs considering spatial variability and correlation in subsurface conditions. A comprehensive parametric study is carried out in this study to investigate the influence of spatial variability in subsurface conditions on the minimum SPT number needed for satisfying an accuracy requirement of site investigation. Random field is adopted to model spatial variation and correlation in soil properties in typical site conditions, and 2D Bayesian compressive sampling is used to interpolate sparse SPT data. Based on the parametric study results, a statistical chart is developed for geotechnical engineers to conveniently select appropriate number of SPTs in a vertical cross-section. Real SPT data from New Zealand are used to illustrate and validate the proposed method.

scholarly journals Liquefaction Characteristics of Sands Based on Cyclic Direct Simple Shear Test

2020 ◽  
Vol 20 (4) ◽  
pp. 239-249
Author(s):  
Byongyoun Hwang ◽  
Tae-Young Kwak ◽  
Jongkwan Kim ◽  
Jin-Tae Han
Keyword(s):  
Simple Shear ◽  
Evaluation Method ◽  
Resistance Ratio ◽  
Test Results ◽  
Liquefaction Resistance ◽  
Ottawa Sand ◽  
Cyclic Resistance ◽  
Direct Simple Shear ◽  
Cyclic Resistance Ratio ◽  
Particle Shapes

In this study, a series of cyclic direct simple shear tests were conducted on Pohang sand, Jumunjin sand, and Ottawa sand. The cyclic resistance ratio (CRR) was derived on the basis of the test results obtained. For verification of the effect of particle distribution on liquefaction resistance, the simplified method for evaluation of the possibility of liquefaction was used to assess these sands. The test results showed that the cyclic resistance ratio of Pohang sand was the lowest, which was consistent with the result of the simplified evaluation method for determining the possibility of liquefaction. In addition, the results showed that the liquefaction resistance increased for particle shapes being more angular than round. Normalization was subsequently applied to minimize the effects of the different factors, and the correlation between the CRR<sub>N=10</sub> normalization curve and the CRR<sub>N=15</sub> normalization curve was confirmed.

scholarly journals Use of surface waves for geotechnical engineering applications in Western Sydney

2013 ◽  
Vol 35 ◽  
pp. 37-44 ◽  
Author(s):  
K. Tokeshi ◽  
P. Harutoonian ◽  
C. J. Leo ◽  
S. Liyanapathirana
Keyword(s):  
Surface Waves ◽  
Linear Array ◽  
Ground Surface ◽  
Vertical Direction ◽  
Site Characterization ◽  
Standard Penetration Test ◽  
Penetration Test ◽  
Non Invasive ◽  
Phase Velocity Dispersion

Abstract. Current in situ methods used to geotechnically characterize the ground are predominantly based on invasive mechanical techniques (e.g. CPT, SPT, DMT). These techniques are localized to the tested area thus making it quite time consuming and costly to extensively cover large areas. Hence, a study has been initiated to investigate the use of the non-invasive Multichannel Analysis of Surface Waves (MASW) and Multichannel Simulation with One Receiver (MSOR) techniques to provide both an evaluation of compacted ground and a general geotechnical site characterization. The MASW technique relies on the measurement of active ambient vibrations generated by sledgehammer hits to the ground. Generated vibrations are gathered by interconnected electromagnetic geophones set up in the vertical direction and in a linear array at the ground surface with a constant spacing. The MSOR technique relies on one sensor, one single geophone used as the trigger, and multiple impacts are delivered on a steel plate at several distances in a linear array. The main attributes of these non-invasive techniques are the cost effectiveness and time efficiency when compared to current in situ mechanical invasive methods. They were applied to infer the stiffness of the ground layers by inversion of the phase velocity dispersion curves to derive the shear wave velocity (Vs) profile. The results produced by the MASW and the MSOR techniques were verified against independent mechanical Cone Penetration Test (CPT) and Standard Penetration Test (SPT) data. This paper identifies that the MASW and the MSOR techniques could be potentially useful and powerful tools in the evaluation of the ground compaction and general geotechnical site characterization.

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