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

Author(s):  
A. Burak Göktepe ◽  
Selim Altun ◽  
Alper Sezer

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.

Author(s):  
Joseph P. Koester ◽  
Chris Daniel ◽  
Michael L. Anderson

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.


Author(s):  
S. Thorburn

AbstractThis introductory lecture discusses the international use of the standard penetration test (SPT) and presents the proposals for International Reference Test Procedures. The application of the SPT as a means of assessing the strength and stiffness of weak rocks is mentioned together with the reliance upon the test at the present time for estimating the liquefaction potential of saturated fine grained non-cohesive soils. The various aspects of the execution of the SPT are discussed which can provide variable and unrepresentative values of resistance (N values).The principle of measuring energy losses and making adjustments to the N values is introduced as a basis for ensuring comparability of test results.Reference is made to the general descriptions of the SPT given in BS 5930:1981 and to the lack of clear guidance in this British Standard.


2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Marcos Fábio Porto de Aguiar ◽  
Fernando Feitosa Monteiro ◽  
Francisco Heber Lacerda de Oliveira ◽  
Yago Machado Pereira de Matos

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.


2015 ◽  
Vol 785 ◽  
pp. 702-706 ◽  
Author(s):  
Khairul Anwar Hatta ◽  
Syed Baharom Azahar Syed Osman

In general practice, soil investigation (SI) incorporating bore hole sampling produced the most reliable value of the relevant soil parameters for the purpose of actual calculation on factor of safety (FOS) in slopes even tough time consuming and very expensive. Assessments of slope stability using electrical parameters have least been research by many scholars due to non-destructive and very sensitive and it is attractive tool for describing the subsurface properties of the slope without disturbing the physical characteristic of the soil. The method has been applied in various contexts like groundwater exploration, agronomical management by identifying areas of excessive or soil horizon thickness and bedrock depth. This paper investigates the relationship between electrical resistivity and SPT-N values of sandy soils. The research work consists of field resistivity surveys, soil boring and soil characterization tests. Field survey included 1D vertical electrical sounding (VES) and SPT method in obtaining SPT-N value. The test being conducted on 3 different areas and 11 sandy soil sample with electrical, physical soil characterization data which being used for least-squares regression method. In this part of the study, correlations of electrical resistivity with SPT values of soil were assessed. The findings showed good correlation between the resistivity and soil properties. The obtained results demonstrate the possibility usage of electrical resistivity survey as an alternative to standard penetration test SPT is possible.


2013 ◽  
Vol 50 (7) ◽  
pp. 793-800 ◽  
Author(s):  
Edgar Giovanny Diaz-Segura

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.


2005 ◽  
Vol 42 (3) ◽  
pp. 856-875 ◽  
Author(s):  
Sheng-Yao Lai ◽  
Ping-Sien Lin ◽  
Ming-Jyh Hsieh ◽  
Hoi-Fung Jim

Discriminant models are developed for evaluating soil liquefaction potential, using standard penetration test (SPT) data for 592 occurrences of liquefaction and nonliquefaction. The discriminant model used is a multivariate statistical method. The square root of the SPT N value, (N1)601/2, and the logarithm of the cyclic stress ratio, ln CSR7.5, are adopted as the major parameters for analyses. Two models measuring liquefaction resistance through the SPT N value are also established in this study, which allows calculated results to be compared with the empirical curves. Key words: liquefaction, discriminant analysis, misclassified probability.


Sign in / Sign up

Export Citation Format

Share Document