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.

Evaluation and use of clustering algorithms for standard penetration test data classification

2014 ◽  
Vol 29 (1) ◽  
pp. 55-64 ◽  
Author(s):  
A. Burak Göktepe ◽  
Selim Altun ◽  
Alper Sezer
Keyword(s):  
Clustering Algorithms ◽  
Standard Penetration Test ◽  
Test Results ◽  
Penetration Test ◽  
N Value ◽  
Fine Grained ◽  
Liquidity Index ◽  
Spt N Value

AbstractThe standard penetration test (SPT) is the most common test conducted in the field, and it is used to determine in situ properties of different soils. Although it is a matter of debate, these tests are also used for the determination of the consistency of fine-grained soils, whereby the test results can also be utilized to establish numerous empirical correlations to predict the strength of soils in the field. In this study, unsupervised clustering algorithms were employed to classify the SPT standard penetration resistance value (SPT-N) in the field. In this scope, shear strength and liquidity index parameters were used to classify the SPT-N values by taking the classification system of Terzaghi and Peck (1967) into consideration. The results showed that the input parameters were successful for classifying the SPT-N value to an acceptable degree of strength attribute. Therefore, in cases where the SPT tests are unreliable or could not be performed, laboratory tests on undisturbed specimens can give valuable information regarding the consistency and SPT-N value of the soil specimen under investigation. Data in this study is based on several tests that were conducted in a region; nevertheless, it is advised that the results of this study should be evaluated using global data.

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.

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.

scholarly journals Determination of Shape Coefficient in Elastic Modulus Estimation with Penetration Test

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Tongbin Zhao ◽  
Rui Mao ◽  
Kai Fang ◽  
Biwen Zhang ◽  
Fenghai Yu
Keyword(s):  
Elastic Modulus ◽  
Soft Rock ◽  
Confining Pressure ◽  
Test Results ◽  
Penetration Test ◽  
Shape Coefficient ◽  
Penetration Behavior ◽  
Penetration Tests ◽  
The Relationship

Elastic modulus is a significant parameter in design and construction for rock engineering. Rock penetration test as a convenient method to evaluate the modulus of rocks has a great potential to be used. Based on the elastic theory, the relationship between rock penetration behavior and elastic modulus was established. In order to evaluate the elastic modulus, the shape coefficient is an important parameter to be determined. However, due to many factors, the value of this parameter is still uncertain. To provide a better insight into the shape coefficient and its factors, a series of penetration tests which used several types of rock samples with different sizes were conducted to study the determination of shape coefficient under different conditions. The test results show that sample size influences the shape coefficient, and with the increase in size, the shape coefficient decreases gradually to a stable value. In contrast, confining pressure has less effect on shape coefficient, and in the moderate and low stresses region, a fixed value can be selected for the test. Different types of rocks correspond to different shape coefficients. The shape coefficient of hard rock is higher than that of soft rock. Shape coefficient should be selected reasonably according to the penetration depth in practical application, and the reason, furthermore, why back-calculated shape coefficient deviates from the theoretical value is also discussed.

Notes on the Correlation of Cone Penetration Test Results in Weak Chalk at Norwich, Norfolk

1986 ◽  
Vol 2 (1) ◽  
pp. 219-221
Author(s):  
H. Erwig ◽  
J. I. Pattinson
Keyword(s):  
Site Investigation ◽  
Standard Penetration Test ◽  
Test Results ◽  
Penetration Test ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Deep Boreholes ◽  
A Site ◽  
Penetration Tests

AbstractA site investigation has been carried out at Norwich, Norfolk consisting of deep boreholes and static electric cone penetration tests. Notes are given on the methods of investigation and on tentative classification of the weak chalk in this area together with the measured parameters of cone end resistance and standard penetration test ‘N’ values.

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 In-situ Desaturation Tests by Electrolysis for Liquefaction Mitigation

2021 ◽  
Author(s):  
Runze Chen ◽  
Yumin Chen ◽  
Hanlong Liu ◽  
Kunxian Zhang ◽  
Ying Zhou ◽  
...  
Keyword(s):  
Minimum Degree ◽  
Electricity Consumption ◽  
Potential Method ◽  
Economic Benefits ◽  
Degree Of Saturation ◽  
Test Results ◽  
Liquefaction Resistance ◽  
The Difference ◽  
Maximum And Minimum Degree

Electrolytic desaturation is a potential method for improving the liquefaction resistance of the liquefiable foundation by reducing the soil saturation. In this study, in-situ desaturation tests were performed to investigate the resistivity of soil at different depth and the water level of the foundation under different current. The test results show that at constant currents of 1 A (Ampere, unit of the direct current), 2 A and 3 A, the saturation of the treated foundation reached 87%, 83% and 80%. During the electrolysis process, the generated gas migrates vertically and horizontally under the influence of buoyancy and gas pressure. In the end of electrolysis, the gas inside the sand foundation basically migrates vertically only. The higher current intensity employed for electrolysis will affect the uniformity and stability of the gas. At constant currents of 1 A, 2 A and 3 A, the difference between the maximum and minimum degree of saturation in the treated foundation was 14%, 18% and 19%; and after electrolysis halted for 144 h, the saturation in the treated foundation was 90%, 85% and 87%. The electricity consumption analysis indicates that the desaturation method has excellent economic benefits in the treatment of saturated sand foundations.

Reliability Analysis of Foundation Settlement in Nigeria Based on Standard Penetration Test Results

Geo-Risk 2017 ◽  
2017 ◽  
Author(s):  
Salahudeen A. Bunyamin ◽  
Ijimdiya S. Thomas ◽  
Eberemu O. Adrian ◽  
Osinubi J. Kolawole
Keyword(s):  
Reliability Analysis ◽  
Standard Penetration Test ◽  
Foundation Settlement ◽  
Test Results ◽  
Penetration Test

Estimating liquefaction-induced ground settlements from CPT for level ground

2002 ◽  
Vol 39 (5) ◽  
pp. 1168-1180 ◽  
Author(s):  
G Zhang ◽  
P K Robertson ◽  
R W.I Brachman
Keyword(s):  
Integrated Approach ◽  
Test Results ◽  
Liquefaction Resistance ◽  
Laboratory Test Results ◽  
Medium Risk ◽  
Major Factors ◽  
Treasure Island ◽  
Silty Soils ◽  
Ground Settlements

An integrated approach to estimate liquefaction-induced ground settlements using CPT data for sites with level ground is presented. The approach combines an existing CPT-based method to estimate liquefaction resistance with laboratory test results on clean sand to evaluate the liquefaction-induced volumetric strains for sandy and silty soils. The proposed method was used to estimate the settlements at both the Marina District and Treasure Island sites damaged by liquefaction during the Loma Prieta, California, earthquake on 17 October 1989. Good agreement between the calculated and measured liquefaction-induced ground settlements was found. The major factors that affect the estimation of liquefaction-induced ground settlements are also discussed in detail. The recommendations for taking the effects of these factors into account in estimating liquefaction-induced ground settlements using the proposed CPT-based approach are presented. It is suggested that the proposed method may be used to estimate liquefaction-induced settlements for low- to medium-risk projects and also to provide preliminary estimates for higher risk projects.Key words: liquefaction, settlements, earthquake, sand, in situ testing.

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