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[pt] Uma extensa campanha de ensaios de cisalhamento direto foi realizada na Areia da Praia de Ipanema, inspirado em Simões (2015). Os ensaios foram realizados em corpos de prova na condição seca, moldados em seis diferentes domínios de compacidade relativa (CR), desde muito fofo até muito compacto. Para cada domínio de CR, foram realizados ensaios sob dez diferentes valores de tensão normal nominal, variando de 25 a 1250 kPa. Em todos os ensaios, foi utilizado um dispositivo desenvolvido para impedir a rotação do top cap. A grande quantidade e variedade de ensaios permitiu uma análise detalhada de como as características das curvas tensão cisalhante sobre tensão normal versus deslocamento horizontal relativo e deslocamento vertical do top cap versus deslocamento horizontal relativo variaram com as variações de CR e de tensão normal, especialmente o ângulo de atrito de pico e o deslocamento vertical do top cap na ruptura, mostrando contração ou dilatação na ruptura. O ângulo de atrito a volume constante da Areia da Praia de Ipanema parece estar situado entre 30 e 32 graus. Uma curva que relaciona índice de vazios crítico e tensão normal nominal crítica foi obtida a partir dos ensaios de cisalhamento direto na Areia da Praia de Ipanema, sendo análoga à linha de estado crítico proposta por Lee e Seed (1967). Ademais, a alta frequência de aquisição de dados tornou explícito o fenômeno conhecido como stick-slip nas curvas obtidas, mostrando que a amplitude do fenômeno é tanto maior quanto menor a tensão normal nominal. / [en] A comprehensive research program of direct shear tests was carried out on Ipanema Beach Sand, inspired by Simões (2015). The tests were carried out on specimens in dry condition, prepared in six different domains of relative density (Dr), from very loose to very dense. For each Dr domain, tests were performed under ten different values of nominal normal stress, ranging from 25 to 1250 kPa. In all tests, a device developed to prevent the rotation of the top cap was used. The large number and variety of tests allowed a detailed analysis of how the characteristics of the Shear stress over normal stress versus relative horizontal displacement curves and top cap vertical displacement versus relative horizontal displacement curves varied with CR and normal stress variations, especially the peak friction angle and the vertical displacement of the top cap at failure, showing contraction or dilation at failure. The angle of friction at constant volume of the Ipanema Beach Sand seems to be situated between 30 and 32 degrees. A curve relating critical void ratio and critical nominal normal stress was obtained from the direct shear tests run on Ipanema Beach Sand, being analogous to the critical state line proposed by Lee and Seed (1967). Moreover, the high frequency of data acquisition made explicit the phenomenon known as stickslip in the obtained curves, showing that the amplitude of the phenomenon is greater the smaller the nominal normal stress.

SammanfattningSättningar i friktionsjord är ett av nutidens kontroversiella problem inom geoteknik. Jordbävningar, trafikrörelser, sprängnings- och pålningsarbeten ger upphov till vibrationer, vilket orsakar sättningar i friktionsjord och estetiska, funktionella samt strukturella byggnadsskador. Idag anser geoteknikerna detta vara en komplicerad utmaning på grund av yttre och oförutsägbara faktorer såsom klimatförändringar. Klimatförändringar kan påverka jordens inre struktur och dess mekaniska egenskaper. Generellt betraktas friktionsjord som god mark, men kan ändå ha ett riskbeteende ur ett geotekniskt perspektiv, speciellt när den utsätts för cykliska eller dynamiska krafter.Studien syftar till att klarlägga hur friktionsjord beter sig under inverkan av vibrationer av olika slag. Studien visar identifiering av risker och olika åtgärdsmetodiker för tidigt skede av nybyggnationsplaneringar samtidigt för konstruerade byggnader.En svensk Standard beskrivs även i studien. Denna baseras på sprängningsvibrationer i jord och är en metod som bedömer de tillåtna riktvärdena för vibrationsnivåerna.Information från litteraturstudier och dokumentärvideor har analyserats och använts vid skrivandet av teoridelen. Ett modellförsök har även genomförts i slutet av arbetet. Modellförsökets effektmål var att kartlägga vibrationspåverkan i friktionsjord och sättningsförloppet ur ett visuellt perspektiv.Resultatet av detta arbete har bland annat visat att cykliska och dynamiska lastpåverkan framkallar sättningar i friktionsjord, som i sin tur medför olika typer av skador på befintliga byggnader byggda på denna jord.Nyckelord: sättning, byggnader, vibrationer, cyklisk lastpåverkan, dynamisk lastpåverkan, geoteknik, sand, friktionsjord, liquefaction. / AbstractSettlements in friction soil are one of today's controversial issues within geotechnics. Earthquakes, traffic, blasting and pile driving work generate vibrations to the existing buildings, causing settlements in friction soil and aesthetic, functional and structural damage. Nowadays the geotechnical engineers consider this as a complicated challenge because of external and unpredictable factors such as climate change. Climate changes affect the soil’s internal structure and its mechanical properties. Generally the friction soil is regarded as good soil, but can still have a risk behavior from a geotechnical perspective, especially in terms of cyclic or dynamic load impact.The study aims to clarify how friction soil behaves under the influence of vibrations in various kinds. The study shows the identification of risks and the intervention methodologies in the early stages of construction plans and constructed buildings simultaneously.A Swedish standard is also described in the study. This is based on blasting vibration in soil and is a method that estimates the permissible guideline values for vibration levels.Information from literature and documentary videos have been analyzed and used for the writing of the theoretical part. A model experiment has also been carried out at the end of the essay. The model experiment’s goal was to identify the impact of vibration in friction soil and settlement progress from a visual perspective.The result of this work has shown that the cyclic and dynamic load impact generates settlements in friction soil, which in turn causes various types of damage to existing buildings built on this soil.Keywords: settlement, buildings, vibrations, cyclic load impact, dynamic load impact, geotechnics, sand, friction soil, liquefaction.

Pollution of air represents the contamination with matter that can affect both humanhealth and the environment. Road dust has been recognized as a dominant source ofparticulate matter and one of the factors that contributes to its development is the useof gritting sand. Gritting sand is being used during snowy winter conditions as atraction control method. During spring season, when snow and ice melt and surfacesdry out, and the influence of traffic, asphalt surface wear, particle ejection from tires,etc; under the effect of their interaction, cause the formation of particulate matter.A general aim of this study was to perform analysis of factors which can be consideredresponsible generating road pollution, with resistance to abrasion of gritting sandbeing a potential key problem. The correlation between the use of studded tires andparticulate matter formation has been considered to be one of major issues in urbanareas.In order to carry out this investigation, an individual study case was considered,measurements indicated that levels of pollution increased even after studded tires werebanned.The literature review revealed important knowledge gaps regarding the quantificationof particulate emissions from non-exhaust sources, most importantly, emissions due tolow quality gritting sanding. At this point, very little information is available thatcould be used for determining the resistance to abrasion of gritting sanding material.This is further supported by numerous institutions and companies, all suggesting thatquality of gritting sand is not taken into consideration. Gritting sand is part of abigger problem which also involves types of pavement, types of tires, weather,background pollution, etc. Furthermore, there is no practical method to characterizewear of resistance of gritting sand.

<p>Recreational beaches of the Great Lakes play a critical role in the quality of life for beach goers and contribute to the economic and environmental health of the Great Lakes region. Over the past decade, concerned local residents, municipalities, and public beach goers have observed the deteriorating beach quality along the shores of the Great Lakes. Numerous problems exist at these beaches including: high levels of <em>E.coli</em>, encroachment of invasive and non-native vegetation, iron staining, loss of sand. However, the more pervasive problem appears to be increased wet conditions at beaches that use to be dry. This study was undertaken to investigate the physical and hydrological factors that control wet and dry beaches, in order to determine why these beaches exist. Combined field, laboratory, and modelling methodologies were used to characterize four beach sites and calibrate beach models along southern Georgian Bay in Tiny Township, ON. The results of this research indicate that there are three interconnected factors that influence wet and dry beaches, including: (1) texture of a beach, (2) depth to the water table, and (3) elevation of the ground surface. Texture is the primary factor that controls the moisture conditions at a beach even though all beaches were classified as sands. This is a consequence of the fact that fine grained sands have significantly higher capillary rise and retain higher moisture contents above the water table compared to coarse grained sands. Depth to the water table influences the moisture conditions at a beach through its association with the relative position of the top of the capillary rise within respect to the surface of the beach. Ground surface elevation influences the depth of sand above the water table at a beach; lower and flatter surface elevations have the water table (and capillary rise) closer to the beach surface than at beaches with steeper elevations. In summary, wet beaches have high moisture contents at and near the surface of a beach (> 10 %), shallow water tables (~ < 50 cm), and flat ground surface elevations. Dry beaches have low moisture contents at and near the surface of a beach (< 10 %), deep water tables (~ > 50 cm), and steep ground surface elevations. Using the numerical model HYDRUS-2D, four calibrated beach models provide a framework for beach managers to gain insights into beach quality issues through scenario testing. Beaches with shallow water tables and flat surface elevations (either natural or human-induced) are at greater risk of becoming wet under high lake level scenarios than beaches with steeper surfaces (dry beaches). Heavy precipitation events are temporary and do not convert dry beaches into wet beaches and high evaporation rates do not convert wet beaches into dry beaches; conversion of beaches is mainly influenced by beach surface alterations (e.g. bulldozing and removing sand dunes). The conclusion of this study is that hydrological factors are primary controls on the quality of the beaches and the associated problems along the shores of the Great Lakes.</p> / Master of Science (MSc)

<p>This thesis investigates the effects of sample preparation methods, which has substantial influence on the internal structure or fabric of the sample, and interparticle locking on the behaviour of sand through experimental study. Extensive laboratory tests were conducted on two sands (namely, Ottawa sand and crushed limestone) with distinct particle shape and surface texture, using a Bishop-type triaxial testing system.</p><p>A total of eight sample preparation methods were used to fabricate specimens with different initial fabric, with specimens being fabricated using water pluviation, moist tamping, and moist rodding. The experimental data reveal that sample preparation methods have significant effect on both deformation characteristics and shear strength of sand, in addition to the density and the effective confining pressure applied to the specimens. More specifically, water pluviation and moist tamping tend to yield specimens of high anisotropy and large dilation, which in turn results in higher friction angle in conventional triaxial compression. The effect of sample preparation methods was also observed from undrained tests on saturated sand.</p><p>Laboratory tests on crushed limestone consisting of angular particles demonstrate that strong interparticle locking may develop owing to particle angularity. The shear resistance of sand with angular particles has contributions from interparticle friction, dilatation and interparticle locking. Moreover, interparticle locking, which largely exists at the peak shear resistance of sand but vanishes with dilation at large deformation, exists under both low and high stress levels investigated in this study. A conceptual model was proposed to take into account the energy consumption associated with breaking interparticle locking during deformation when estimating the dilatancy and strength of granular soils.</P><P>The behaviour of sand along proportional strain paths was also investigated, with the focus being placed on strain softening and material instability in the context of Hill's second order work. Depending on the strain path or the deformation history, a dilatant sand displaying hardening and stable behaviour under isochronic (undrained) conditions, which is often used as a reference in soil mechanics, may succumb to unstable flow type behaviour along dilative strain paths. More specifically, when the imposed rate of dilation exceeds the inherent rate of dilation of the material, a dense sand specimen will have flow failure similar to that of a saturated loose specimen subjected to undrained compression. On the other hand, a loose sand may not have a flow failure when it is forced to have contractive volume change along imposed strain paths.</P> / Thesis / Master of Science (MSc)