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.

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.

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.

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.

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 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.

Cone penetration testing in stiff glacial soils using a downhole cone penetrometer

1992 ◽  
Vol 29 (3) ◽  
pp. 448-455
Author(s):  
Curtis R. Treen ◽  
Peter K. Robertson ◽  
David J. Woeller
Keyword(s):  
Penetration Resistance ◽  
Standard Penetration Test ◽  
Cone Penetrometer ◽  
Penetration Test ◽  
Cone Penetration ◽  
Penetration Testing ◽  
Cone Penetration Testing ◽  
Geotechnical Investigations ◽  
Drilling Rigs

Cone penetration testing (CPT) in Canada is usually performed using locally available drilling rigs. The limited pushing capacity of most drilling rigs coupled with the risk of damage to expensive cone penetrometers has tended to restrict the CPT to generally loose or soft soils. Therefore, in regions dominated by stiff glacial soils the more rugged standard penetration test (SPT) is still the most commonly used in situ test during geotechnical investigations. However, there are many limitations with the SPT with respect to interpretation and repeatability, especially the uncertainty with the energy delivered from various SPT hammer anvil systems. A downhole cone penetration test (DCPT) has been developed by modifying the equipment and procedure of the standard electric CPT. The DCPT consists of a simple, inexpensive electric cone penetrometer attached to a 1.5 m (5 ft) length of AW drill rod. The test is performed by pushing the cone 1.5 m into the base of an open borehole to produce a continuous profile of penetration resistance Qc, over the 1.5-m interval or whatever interval penetration is possible. The test incorporates the simplicity, ruggedness, and depth capability of the SPT but is able to define a near-continuous, accurate, and repeatable cone penetration resistance profile. The equipment and procedure of the DCPT is described in detail, and results from a near-continuous DCPT and an adjacent continuous CPT are presented and compared with the results obtained from an adjacent borehole with SPT. Excellent agreement was found between the results of the DCPT and the CPT. Key words : in situ, cone penetration testing, stiff soils.

scholarly journals Análisis de las correlaciones existentes del ángulo de fricción efectivo para suelos del piedemonte oriental de Bogotá usando ensayos in situ

TecnoLógicas ◽  
2015 ◽  
Vol 18 (35) ◽  
pp. 93 ◽  
Author(s):  
July E. Carmona-Álvarez ◽  
Juan C. Ruge-Cárdenas
Keyword(s):  
Standard Penetration Test ◽  
Penetration Test

Estimar el ángulo de fricción efectivo del suelo a partir de ensayos in situ es una tarea complicada debido a las altas tasas de deformación existentes en este tipo de ensayos, que tienden a ser demasiado invasivos y perturban las vecindades de la profundidad del ensayo y aún la muestra que eventualmente se toma en el sitio. Así mismo, la mayoría de correlaciones encontradas en la literatura actual, para obtener el ángulo de fricción efectivo, usando ensayos de campo han sido desarrolladas para suelos de otras latitudes, por tal razón al ser implementadas en suelos tropicales presentan alta dispersión, cuando se desea comparar los valores de parámetros de campo, con los resultados reales obtenidos en el laboratorio. Esta investigación busca mediante el uso de ensayos in situ, definir por medio de análisis de diferentes correlaciones, cuál de estas se ajusta mejor a las condiciones propias de suelos del piedemonte de la ciudad de Bogotá, la cual se considera la problemática primordial a resolver en el artículo. Para el presente estudio serán utilizados datos provenientes del SPT - Standard Penetration Test (de amplio uso en Colombia) y SPT-T Standard Penetration Test + Torque (nunca antes llevado a cabo en el país), realizados teniendo en cuenta la normativa acorde para cada ensayo. Considerando que para el SPT-T no existe norma local que rija este tipo de ensayos. Las correcciones por procedimientos de campo de los ensayos que se implementaron fueron realizadas por confinamiento efectivo y transferencia de energía del martillo golpeador, ya que en el estado del arte del tema son definidos como los que influyen de manera directa en la confiabilidad de los resultados. Los resultados finales muestran la tendencia de cada una de las metodologías usadas para obtener la correlación, en relación con el valor real del ángulo de fricción efectivo, obtenido de ensayos de laboratorio.

Standard penetration test energy measurements using a system based on the personal computer

1992 ◽  
Vol 29 (4) ◽  
pp. 551-557 ◽  
Author(s):  
Peter K. Robertson ◽  
David J. Woeller ◽  
Kofi O. Addo
Keyword(s):  
Energy Transfer ◽  
Test Procedure ◽  
Standard Penetration Test ◽  
Energy Calibration ◽  
Calibration System ◽  
Penetration Test ◽  
Reference Test ◽  
Time Record ◽  
Force Time

According to the International Reference Test procedure for the standard penetration test (SPT), in situations where comparisons of SPT results are important, calibrations should be made to evaluate the efficiency of the equipment in terms of energy transfer. However, equipment to measure the energy transfer of the hammer anvil system is not commonly available. Ten years ago a system was developed and made commercially available. However, this system is no longer available. An SPT energy calibration system is described that has been developed based on a microcomputer. The load cell to measure the compressive stress wave beneath the SPT anvil consists of a 0.5-m length of strain-gauged AW rod. Specialized software has been developed to record the force–time record for each hammer blow on a portable microcomputer. Examples of energy measurements are presented and discussed. Key words : standard penetration test, in situ, microcomputer, energy.

scholarly journals A first study on earth-air heat exchanger in Pelotas

2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Eduardo De Sá Bueno Nóbrega ◽  
Ruth Da Silva Brum ◽  
Jairo Valões de Alencar Ramalho ◽  
Régis Sperotto Quadros
Keyword(s):  
Standard Penetration Test ◽  
Subtropical Climate ◽  
Penetration Test ◽  
In Situ Data ◽  
The Earth ◽  
Air Conditioning Systems ◽  
A Site ◽  
The City

Earth-air heat exchangers (EAHE) represent a promising option to reduce theheating/cooling load of buildings. Unlike traditional air conditioning systems, the EAHE employ a renewable source of energy and they can work using low electric power. Basically, EAHE employ underground ducts where the air is blown to exchange heat with the ground. Since the superficial layers of the Earth are warmer than outside air in winter and cooler than it in summer, the soil canbe used as a heat source or sink. Therefore, the air leaves the ducts at milder temperatures. Recent research has shown that the Brazilian south region, where prevails a subtropical climate, has a high potential for the use of EAHE. However, such references are still very limited. Hence, this work aims to analyze the thermal performance of EAHE considering the city of Pelotas, located in the south Brazilian state of Rio Grande do Sul. As a case study, we used in situ data, covering thesoil geotechnical profiles from a site in the city, which were obtained by a standard penetration test (SPT). To make the computer simulations, we used an analytical model, which was previously tested and validated. The results point out good prospects for the installation of these devices in the city of Pelotas, taking advantage of its geological potential

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