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No description available.

Urban construction sites require strict control of their environmental impact, which, for vibratory sheet pile driving, can include damage to nearby structures due to ground vibrations. However, the lack of knowledge concerning the generation of soil vibrations makes the prediction of ground vibration levels difficult. This MSc. thesis in particular, focuses on a crucial link in the vibration transfer chain: the sheet pile – soil interface, which is also one of the least documented. The aim of this thesis is first, to carry out a full-scale field test consisting in the monitoring of sheet pile and ground vibrations during sheet pile vibratory driving. And second, to analyze a selected portion of the collected data with focus on the sheet pile – soil vibration transfer. Both aspects of the thesis work aim, more generally, to contribute to the understanding of ground vibration generation under vibratory sheet pile driving. The full-scale field study was performed in Solna in May 2013. It consisted in the vibratory driving of seven sheet piles, out of which three were fitted with accelerometers. During the driving, ground vibrations were measured by accelerometers, the closest ones placed only 0.5 m from the sheet pile line. The design and installation of the soil instrumentation was innovative in as much as accelerometers were not only set on the ground surface but also at three different depths (~ 3 m, 5 m and 6 m). The analysis presented in this thesis is primarily a comparison between sheet pile vibrations and ground vibrations measured 0.5 m from the sheet pile line. The principal aspects considered in the comparison are: the influence of penetration through different soil layers, the sheet pile – soil vibration transfer efficiency, the frequency content of sheet pile and soil vibrations, and differences between toe- and shaft-generated vibrations. The main conclusions from this study are:  Most of the vibration loss occurs in the near field: 90-99% of the sheet pile vibration magnitude was dispersed within 0.5 m from the driven sheet pile. Moreover, the sheet pile – soil vibration transfer efficiency was reduced for higher sheet pile acceleration levels and higher frequencies.  The soil characteristics strongly influence the sheet pile vibration levels. A clear distinction could be made between "smooth" and "hard" driving, the latter being associated with an impact situation at the sheet pile toe.  The focus of ground vibration studies should not only be the vertical vibrations. Indeed, the ground vibrations’ horizontal component was found to be of the same or even higher magnitude than the vertical component.

In this study, a new vector form intrinsic finite element (VFIFE) for the plate is developed and applied to study the responses of a traditional plate member applied to engineering structures. The VFIFE method is a solution procedure for the mechanic problems by adopting the traditional co-rotational explicit finite element method developed by Belyschko and Hsieh (1973). Three different shape-functions including the simplest polynomial form shape-function (Poly), non-conforming area coordinate shape-function (BCIZ) and the conforming area coordinate shape-function (BCIZC) are utilized to simulate the displacement field of the plate. For a system with nonzero rigid-body displacement, the equilibrium will be difficult to achieve in the global coordinate system when the traditional finite element method is applied. By separating the rigid-body motions from the deformed motions, this problem can be easily taken care. In numerical examples, the accuracy and efficiency of this new developed vector form intrinsic finite element for plate simulation are also examined. It is found that compared to the analytical solution, the accuracy is excellent, while compared to traditional finite element method, the efficiency is also encouraging. This new VIFIFE plate element was also applied to the analysis for the sheet plate members in the harbor structures such as the sheep-pile wharf structural system. It was found that not only can the global behaviors of the pile be clearly observed but also local variations in deformations of the steel sheet are clearly shown.

Vibratory driving is today the most common installation method of sheet piles. The knowledge of the induced ground vibrations is however still deficient. This makes predictions of the vibration magnitudes difficult to carry out with good reliability. To avoid exceeding the limit values, resulting in stops of production, or that vibratory driven sheet piles are discarded for more costly solutions, a need for increased knowledge of the vibration process is imminent. With increased knowledge, a more reliable and practical prediction model can be developed.  The aim of this thesis is to analyze measured data from a field study to increase the understanding of the induced vibrations and their propagation through the soil. The field study was performed in Karlstad in May 2010, where a trial sheet piling prior to an extension of Karlstad Theatre was carried out. During the trial sheet piling, two triaxial geophones were mounted at the ground surface at two different distances from the sheet piles, to measure the vibration amplitude. The field test is associated with some limitations. Only four sheet piles were driven, with one measurement per sheet pile. Some measurements were less successful and some parameters had to be assumed. This limits the accuracy but still provides some interesting results. Another aim is to compare the measured values to existing models for predicting vibrations from piling and sheet piling operations. There are today several prediction models available, which however often provide too crude estimations or alternatively are too advanced to be incorporated in practical use. Two basic empirical prediction models are compared to the measured values in Karlstad, where the first is one of the earliest and most well known models and the other is a later development of the first model. The purpose of this comparison is to evaluate these models to contribute to the development of a new prediction model. The results show that the earlier model greatly overestimates the vibration magnitude while the later developed model provides a better estimation.  A literature study is performed to gain a theoretical background to the problem of ground vibrations and how they are related to the method of vibratory driving of sheet piles. The analysis considering the field study and prediction models is mainly performed by using MATLAB to obtain different graphical presentations of the vibration signals. The conclusions that can be drawn from the results are that the focus of vibration analysis should not always be the vertical vibration components. Horizontal movements of the sheet pile might be introduced, e.g. by the configuration of the clamping device, which generates additional vibrations in horizontal directions. The soil characteristics influence the magnitude of the vibrations. As the sheet pile reaches a stiffer soil layer, the vibration magnitude increases. A realistic and reliable prediction model should take the characteristics of the soil into account.

No description available.

Ground vibrations due to pile driving are part of a complex process. Vibration is generated from the pile driver to the pile. As the pile interacts with the surrounding soil, vibrations are transferred at the pile-soil interface. The vibration propagates through the ground and interacts with structures, both above ground and underground. The vibration continues into the structure where it may disturb occupants and/or damage the structure. In this thesis the study of the vibration transfer process due to pile driving is limited to the vibration source and the wave propagation in the soil. Vibration transmission to adjacent buildings and structures is not studied. However, impact of vibrations on buildings is briefly discussed in the literature study. It is important to accurately predict the magnitude of ground vibrations that result from pile driving in urban areas, both over- and underestimated vibration levels lead to increased costs. A lot of research has been performed within this field of knowledge, but a reliable and acknowledged prediction model for vibrations induced by pile or sheet pile driving is still needed. The objective of the research project is to increase the knowledge and understanding in the field of ground vibrations due to impact and vibratory driving of piles and sheet piles. This research project also aims to develop a reliable prediction model that can be used by practising engineers to estimate vibration due to pile driving. This licentiate thesis presents the first part of the research project and aims to increase the knowledge and understanding of the subject and to form a basis for continued research work. The most important findings and conclusions from this study are: The main factors influencing vibrations due to pile and sheet pile driving are; (1) the vibrations transferred from the pile to the soil, (2) the geotechnical conditions at the site and (3) the distance from the source. The vibrations transmitted from the pile to the soil depend on the vibrations transferred to the pile from the hammer, the pile-soil interaction and the wave propagation and attenuation in the plastic/elasto-plastic zone closest to the pile. There is today no prediction model that fulfils the criteria of the “perfect” prediction model; reliable but yet easy to apply. Future research should study the transfer of vibrations at the pile-soil interface, including the generation of a plastic/elasto-plastic zone in the area closest to the pile and how that affects the transfer of vibrations from the pile to the soil. / Markvibrationer på grund av pålning är del av en komplex process. Vibrationer genereras från pålmaskinen till pålen. När pålen kommer i kontakt med den omgivande jorden överförs vibrationer mellan påle och jord. Vibrationerna fortplantar sig som vågor genom marken och träffar byggnader och andra konstruktioner, både ovan och under jord. Vibrationerna fortsätter in i byggnaden där de kan orsaka störningar eller skador. I denna avhandling begränsas studien av vibrationsöverföringsprocessen till vibrationskällan och vågutbredningen i jord. Vibrationsöverföringen till intilliggande byggnader eller konstruktioner har inte studerats. Påverkan av vibrationer på byggnader diskuteras dock kort i litteraturstudien. Det är viktigt att på ett tillförlitligt sätt kunna förutsäga markvibrationerna på grund av pålning i stadsmiljö, både över- och underskattade vibrationsnivåer leder till ökade kostnader. Forskning har tidigare utförts inom detta område, men en tillförlitlig och allmänt accepterad prognosmodell för vibrationer på grund av pålning eller spontning saknas fortfarande. Syftet med forskningsprojektet är att öka kunskapen och förståelsen för markvibrationer som uppkommer vid installation genom slagning eller vibrering av pålar och spont. Forskningsprojektet syftar också till att utveckla en tillförlitlig prognosmodell som kan användas av yrkesverksamma ingenjörer för att uppskatta vibrationsnivåer orsakade av pålning. Denna licentiatavhandling presenterar den första delen av forskningsprojektet och syftar till att öka kunskapen och förståelsen inom ämnesområdet samt att skapa en plattform för det fortsatta forskningsarbetet. De viktigaste resultaten och slutsatserna från denna studie är: De huvudsakliga faktorer som påverkar vibrationer orsakade av pålning är; (1) de vibrationer som överförs från källan till jorden, (2) de geotekniska förhållandena på platsen och (3) avståndet från vibrationskällan (pålen). Vibrationerna som överförs från pålen till jorden beror på de vibrationer som överförs från pålmaskinen till pålen, påle-jord interaktionen samt vågutbredning och dämpning i den plastiska/elasto-plastiska zonen som bildas närmast pålen. Det finns idag ingen prognosmodell som uppfyller kriterierna för den ”perfekta” prognosmodellen; tillförlitlig men ändå lätt att tillämpa. Framtida forskning bör undersöka överföringen av vibrationer mellan påle och jord, innefattande uppkomsten av en plastisk/elasto-plastisk zon närmast pålen och hur det påverkar vibrationsöverföringen från påle till jord. / <p>QC 20130314</p>

Geotechnical engineering is strongly associated with large uncertainties. Exploring a medium (soil) that is almost entirely and completely hidden from us is no easy task. Investigations can be made only at discrete points, and the majority of a specific soil volume is never tested. All soils experience inherent spatial variability, which contributes to some uncertainty in the design process of a geotechnical structure. Furthermore, uncertainties also arise during testing and when design properties are inferred from these tests. To master the art of making decisions in the presence of uncertainties, probabilistic description of soil properties and reliability-based design play vital roles. Historically, the observational method (sometimes referred to as the “learn-as-you-go-approach”), sprung from ideas by Karl Terzaghi and later formulated by Ralph Peck, has been used in projects where the uncertainties are large and difficult to assess. The design approach is still highly suitable for numerous situations and is defined in Eurocode 7 for geotechnical design. In paper I, the Eurocode definition of the observational method is discussed. This paper concluded that further work in the probabilistic description of soil properties is highly needed, and, by extension, reliability-based design should be used in conjunction with the observational method. Although great progress has been made in the field of reliability-based design during the past decade, few geotechnical engineers are familiar with probabilistic approaches to design. In papers II and III, aspects of probabilistic descriptions of soil properties and reliability-based design are discussed. The connection between performing qualitative investigations and potential design savings is discussed in paper III. In the paper, uncertainties are assessed for two sets of investigations, one consisting of more qualitative investigations and hence with less uncertainty. A simplified Bayesian updating technique, referred to as “the multivariate approach”, is used to cross-validate data to reduce the evaluated total uncertainty. Furthermore, reliability-based design was used to compare the two sets of investigations with the calculated penetration depth for a sheet-pile wall. The study is a great example of how a small amount of both time and money (in the pre-investigation phase) can potentially lead to greater savings in the final design. / <p>QC 20160201</p> / TRUST, Transparent Underground Structures

In many construction works in urban areas vibratory driving is the most widely used technique toinstall sheet piles. But due to vibration-sensitive equipment and structures the amount of inducedground vibration need to be minimized. Hence, it is important to select appropriate vibratorparameters that will minimize the level of induced ground vibration.The main objective of this thesis is to study the effect of the vibratory parameter eccentricmoment (vibrator displacement amplitude) on the induced ground vibration during sheet piledriving. To achieve the objective, a literature review and a full-scale field test has beenconducted. The literature review was conducted to provide guidance for the evaluation of thefield test results.The field study was performed in Uppsala in June 2018, where a series of six sheet pile drivingtests were conducted, the first three sheet piles were driven with lower vibrator displacementamplitude and the next three with higher vibrator displacement amplitude, but the same drivingfrequency was used for all six sheet piles. Five tri-axial accelerometers were used to measure thevibration amplitude on vibrator, sheet pile and ground.Important findings of the field study confirmed that, driving sheet piles with higher eccentricmoment will induce lower ground vibration and higher sheet pile penetration speed incomparison to driving with lower eccentric moment. Limitations and possible future researchworks are pointed out. / I många byggnadsarbeten i tätorter är vibrerade drivning den mest använda tekniken för attinstallera sponter. Men på grund av vibrationskänslig utrustning och konstruktioner måstemängden inducerad markvibration minimeras. Därför är det viktigt att välja lämpligavibratorparametrar som minimerar graden av inducerad markvibration.Huvudsyftet med detta examensarbete är att studera effekten av vibrationsparameternsexcentriskamoment (vibratorförskjutningsamplituden) på den inducerade markvibrationen underspontdrivning. För att uppnå målet har en litteraturöversikt och en fullskalig fältundersökning utförts. Litteraturstudien genomfördes för att ge underlag för utvärderingen av fältundersökningenresultanten.Fältstudien utfördes i Uppsala i juni 2018, där en serie av sex spontdrivnings test utfördes, deförsta tre sponten kördes med lägre vibrator-förskjutningsamplitud och de närmaste tre medhögre vibrator-förskjutningsamplitud, men samma körfrekvens användes för alla sex sponter.Fem treaxiala accelerometrar användes för att mäta vibrationsamplituden på vibratorn, spontenoch jorden.Slutsatserna från fältstudien bekräftade att körsponter med högre excentriskt moment kommer attinducera lägre vibrationer och högre penetrationshastighet för sponten i jämförelse med körningmed lägre excentriskt moment. Begränsningar och möjliga framtida forskningsarbeten påpekas.

A model study on laterally braced sheet pile walls retaining cohesionless soil was conducted using 1-g shaking table. Lateral dynamic earth pressures, backfill accelerations and dynamic displacement of walls were measured. Input accelerations were kept between 0.03g to 0.27g. A data acquisition system consisting of dynamic pressure transducers, accelerometers, displacement transducer, signal conditioning board and a data acquisition card compatible with a personal computer was used during the study. Three different walls with thicknesses of 6.6, 3.2 and 2.0 mm were used in order to investigate the effects of changing wall stiffness value on lateral seismic pressures developed on the wall. In addition to that, steel blocks were placed on top of the backfill in order to simulate a surcharge effect of 1.57 kPa to 3.14 kPa during shaking. Amplification of input acceleration, incremental seismic lateral thrusts and corresponding maximum dynamic pressures, application point of the resultant, effect of stiffness and surcharge on maximum seismic lateral thrust and dynamic wall deflections were calculated by processing raw data stored. The results were compared to previous model studies and some analytical methods available.