Fernando Schnaid

In-situ testing in geomechanics : the main tests

Foreword Preface Acknowledgements List of symbols Introduction General considerations Codes of practice Interpretation methods Scope and purposes Standard penetration test (SPT) General considerations Standards and procedures Wave propagation analysis Measurements and corrections Characterization and classification Soil properties in granular materials Soil properties in cohesive materials Soil properties in bonded soils Soil properties in weak rock Direct design methods Soil liquefaction Concluding remarks Notes Piezocone penetration test (CPTU) Equipment and procedures New developments Specifications and standards Test results Soil classification Interpretation methods Soil properties in cohesive materials Granular soils Properties in silty soils Properties in bonded geomaterials Pile bearing capacity Liquefaction Notes Vane test General considerations Equipment and procedures Interpretation Shear strength Stress history Notes Pressuremeter tests General considerations Types of instruments Calibration procedures Experimental results Analysis of pressuremeter tests Pressuremeter tests in sand Cone pressuremeter tests in clay and sand Pressuremeter tests in cohesive-frictional soils Pressuremeter tests in unsaturated soil conditions Design rules Flat dilatometer test (DMT) General considerations Equipment and procedures Intermediate DMT parameters Interpretation of test results Soil characterization Geotechnical parameters in clay Geotechnical parameters in sand Direct applications Design parameters: guidelines Clay Sand 282 Residual soils Stiffness References and further reading Index

Field Tests on Laterally Loaded Rigid Piles in Cement Treated Soils

AbstractA series of laterally loaded pile tests carried out both in natural ground and in cemented treated soil is presented in this paper. The length to diameter ratio L/D of the piles was selected as 5, representing the behavior of a free-headed, short pile that will move as a rigid body in the direction of the applied load without structural damage. The extent of the treated soil layer around the pile ranged from 2–4 times the pile diameter and 0.1–0.3 times the pile length. The treated layer was a mixture of Osorio sand and early strength portland cement. Experimental results show a significant increase in lateral load resistance of short piles when the soil is treated with cement.

Uplift Performance of Anchor Plates Embedded in Cement-Stabilized Backfill

A series ofpullout testsis presentedinthispaper andis usedtoidentifythekinematicsof failureandtheuplift responseofcircular anchor platesembeddedinsand-cementstabilizedlayersatdistinctnormalizedembedmentdepths(H/D), where H is the thickness of the treated layer andD is the diameter of the anchor plates. Experimental results show that the uplift capacity of anchor plates embedded in sand backfill layers increases considerably after mixing 3% cement with the backfill material. Distinct failure mechanisms observed for anchor plates embedded in both sand and cement-stabilized backfills are shown to be a function of H/D. The addition of cement to the sand backfill leads to an increase in uplift capacity of 9 timesfor anH/Dratio of 1.0 and of 13 times for an H/Dratio of 2.0. For sand backfill withH/D51:0, the failure surface had a truncated cone shape withaverticalinclinationof22� ,whereasforH/Dof1.5and2.0,radialcrackingwasobserved,and finalfailuresurfaceshadinclinationsof26and30� , respectively.Pulloutofanchorplatesincement-stabilizedbackfillsatH/Dratiosrangingfrom1.0to2.0exhibittwodistinctcharacteristics:(a)alinear elasticdeformationresponseatsmallpulloutdisplacementsand(b)alaterstagewhereradialfracturingofthestabilizedbackfillleadstohardeningjust prior to failure. Radial cracks starting at the top of the layer near the center of the anchor plates start to propagate only at about 90% of the final uplift failure load, irrespective of H/D. DOI: 10.1061/(ASCE)GT.1943-5606.0000785.

Enhancing bioremediation of diesel oil and gasoline in soil amended with an agroindustry sludge.

Abstract This paper presents a study of the bioremediation of diesel oil and gasoline by a series of controlled laboratory tests. Sludge from an agroindustry was used to enhance biore-mediation of both gasoline and diesel oil mixed with a soil mass to compare its efficiency with that of a mineral fertilizer. Effects of soil microbiology and soil mixtures were investigated by means of evolution of CO2, micro-organism populations at 90 days, pH at 65 and 95 days, mineral nitrogen, and gas chromatographic analysis of the benzene, toluene, methyl tertiary butyl ether, C8, and C9+total aromatics at the end of the experiments. Treatments containing sludge showed better soil conditions after 170 days of treatment (inorganic nitrogen and microbiota activity) compared with gasoline and diesel oil without amendments. Samples had no detectable traces of the measured hydrocarbons at 170 days of treatment.

Prediction of Soil Properties from the Concepts of Energy Transfer in Dynamic Penetration Tests

Results from dynamic penetration tests are traditionally interpreted on the basis of empirical correlations, this being a frequent criticism to these tests. An alternative rational method of interpretation is proposed in this paper from which the energy delivered to the composition of rods is used to calculate a dynamic force that represents the reaction of the soil to the penetration of the sampler ( Fd ) . Interpretation of soil properties both in sand and clay is based on this calculated dynamic force from which the internal friction angle and the undrained shear strength can be estimated. This is achieved from a simple combination of limit equilibrium analysis and cavity expansion theory. Case studies gathered from the Brazilian experience are reported in this paper to illustrate the applicability of the proposed approach.

Tecnologia educacional: apoio à representação do professor de Ciência e Tecnologia e instrumento de estudo para o aluno

O artigo discute a necessidade de desenvolver, junto aos professores de Ciencia e Tecnologia, a capacidade de representacao dos conteudos que ministram, em multiplas linguagens, apoiadas em diferentes meios de comunicacao, ou tecnologias educacionais, sejam elas interativas ou convencionais, como forma de agregar valor ao seu proprio trabalho, qualificando o produto de sua pesquisa. Mesmo que a transmissao de conhecimento nao seja considerada como a atividade preponderante do contexto da relacao professor-aluno, educadores nao devem descuidar do planejamento de elementos destinados a enriquecer a exposicao de conteudos, nos momentos em que isto se fizer necessario, seja em atividades presenciais ou a distância. Necessitam, para tanto, desenvolver habilidades especificas para conhecer e explorar as linguagens e os recursos tecnologicos oferecidos pelos ambientes de producao e disponibilizacao de multimidia, bem como de midias convencionais, como as apresentacoes orais, os livros ou mesmo o quadro (negro, verde ou branco). Alem da reflexao sobre a importância de diferentes tecnologias educacionais na atividade docente, bem como no suporte do estudo dos alunos, serao relatadas experiencias de producao de tres CDs didaticos e de uma serie de videos destinados, as quais descrevem objetivos, dificuldades e potencialidades desse tipo de midia.

Tecnologia educacional: mídias e suas linguagens

O trabalho reflete sobre a natureza da integracao, atraves do computador, de linguagens de multiplos meios de comunicacao, como o video, o audio e as animacoes, sugerindo a necessidade de se planejar a sinergia entre elas, em produtos de hipermidia educacional, atendendo as caracteristicas de suas linguagens especificas, estruturadas e ja consolidadas pelo uso como veiculo de comunicacao social, anterior a sua integracao pelos computadores. Sugere que o uso adequado dessas linguagens especificas favorece o processamento cognitivo dos alunos, em funcao do reconhecimento de padroes de visualizacao, de ritmo de apresentacao e de narratividade, que compoem o seu proprio repertorio de representacoes. Descreve o dialogo de linguagens propiciado pela hipermidia como uma marca ja integrada ao panorama visual – e, portanto, cultural e cognitivo - da comunicacao social do Seculo XXI, observavel tanto na producao de produtos para a Web quanto na composicao de elementos que formam as imagens da televisao contemporânea. Apresenta exemplos de pesquisa de uso de videos e animacoes, com suas respectivas linguagens, aplicadas em tecnologia informatizada para uso educacional, presencial e a distância, em produtos desenvolvidos pelo Nucleo de Multimidia e Ensino a Distância da Escola de Engenharia da Universidade Federal do Rio Grande do Sul, equipe a qual pertencem os autores.

On the mechanics of dynamic penetration tests

This paper describes a numerical model developed to simulate the wave propagation in an elastic media that is applied to in situ dynamic penetration test devices currently used for site characterization. In the model, dynamic equilibrium equations are solved by finite difference analysis in the time domain to produce the discretization of a penetration system – including hammer, rod, penetrometer (or sampler) and soil. In standard penetration tests numerical simulations are shown to agree well with energy measurements derived from force and acceleration signals produced by the impact of a hammer. A parametric study allowed the identification of the relevant factors affecting penetration by demonstrating that the energy effectively delivered to the soil is a function of hammer height of fall and weight of both hammer and rods, as well as the permanent penetration of the penetrometer into the ground produced by a single stroke. Based on these evidences, an approach is suggested to compare results from different dynamic penetration tests without the need to rely on empirical correlations, which is achieved by demonstrating that different equipments should yield the same normalized energy once the influence of both the hammer and rod potential energies are properly considered.

Considerações sobre uso de modelo construtivista no ensino de Engenharia: disciplina de projeto com graduandos e mestrandos

O artigo descreve e analisa uma experiencia de aplicacao do modelo construtivista de ensino-aprendizagem na Engenharia Civil, em aulas presenciais e a distância. Foi apoiada na hipermidia educacional composta de videos, livros, lâminas audiovisuais e outros recursos disponiveis em ambiente virtual, integradas a ferramentas de comunicacao sincrona e assincrona, material desenvolvido como parte de pesquisa realizada ha cerca de dois anos pelo Nucleo de Multimidia e Ensino a Distância da Escola de Engenharia da Universidade Federal do Rio Grande do Sul. A experiencia teve como base a formulacao de Jean Piaget para o processo de aquisicao do conhecimento, atraves da epistemologia genetica, ideia que posiciona o aluno no centro do fenomeno educacional. Apresenta resumidamente esse conjunto de ideias e o material disponibilizado. e seu uso integrado as atividades propostas aos alunos. Analisa aspectos relevantes relacionados a implantacao do modelo para atender necessidades especificas do ensino de conteudos complexos e extensos, caso da Engenharia. Aponta para a continuidade da pesquisa, a partir da avaliacao dos resultados

Piezocone Penetration Rate Effects in Transient Gold Tailings

AbstractThe drainage conditions during cone penetration is a critical factor in the assessment of tailing properties, as the sedimentation process produces deposits that are spatially variable, and...