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.

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 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.

Vibratory driven sheet piles are a cost-effective retaining wall structure, and in coming decades the continued use of this method will be crucial for minimising costs within the construction sector. However, vibratory driven sheet piles are a source of ground vibrations, which may harm structures or induce disturbance. Most urban construction projects face strict limits on permissible vibration level. Being able to reliably predict the expected vibration level prior to construction is therefore highly important. Reliable prediction demands a profound knowledge of the vibration transfer process, from source to point of interest. This thesis focuses on clarifying the vibration transfer process and will serve as a platform for the future development of a reliable prediction model. The vibration transfer process is divided into two main parts: vibration source and vibrations in soil. The different parts in the vibration transfer process are studied and investigated with the help of a literature review, field tests and numerical modelling. Within the scope of this thesis, three field tests have been conducted and a new instrumentation system has been developed. The new instrumentation system enables recording of both sheet pile vibrations and ground vibrations at depth during the entire driving. The field tests aimed to study the vibration transfer from sheet pile to soil and the vibration transfer within a sheet pile wall, as well as the wave pattern in soil. To study sheet pile behaviour during driving a numerical model was developed, which is also meant to serve as a basis for further studies. The main scientific contribution of this thesis is the identification of the sheet pile behaviour during driving. For practical application, the main contribution is the development of an increased knowledge of the vibration transfer process from source to soil, together with the new instrumentation system and the development of the numerical model. / Vibrodriven spont är en kostnadseffektiv stödkonstruktion och i framtiden kommer den fortsatta användningen av denna metod att vara nödvändig för att minimera kostnader för byggprojekt. Vibrodriven spont är dock en källa till markvibrationer, som kan skada byggnader eller orsaka störningar. De flesta byggprojekt måste förhålla sig till strikta krav gällande vibrationsnivåer. Möjligheten att på ett tillförlitligt sätt förutsäga vibrationsnivåerna innan bygget startar är därför av största vikt. Tillförlitlig prognos av vibrationsnivåer i samband med vibrodrivning av spont kräver god kännedom om vibrationsöverföringsprocessen, från källan till det potentiella skadeobjektet. Denna avhandling fokuserar på att förtydliga vibrationsöverföringsprocessen och fungera som en plattform för framtida utveckling av en tillförlitlig prognosmodell. Vibrationsöverföringsprocessen delas in i två huvuddelar; vibrationskällan och vibrationer i jord. De olika delarna av vibrationsöverföringsprocessen studeras och undersöks med hjälp av litteraturstudie, fältförsök och numerisk modellering. Inom ramarna för denna avhandling har tre fältförsök utförts och ett nytt instrumenteringssystem har utvecklats. Det nya instrumenteringssystemet möjliggör mätning av både spontvibrationer och vibrationer på djup i jorden, under hela neddrivningsfasen. Fältförsöken syftade till att studera vibrationsöverföringen mellan spont och jord, vibrationsöverföringen inom en spontvägg samt vågmönstret i jorden under drivning. För att studera spontens beteende under neddrivning utvecklades en numerisk modell, som också kan fungera som en bas för framtida studier. Avhandlingens huvudsakliga vetenskapliga bidrag är identifieringen av spontens beteende under neddrivning. För praktisk tillämpning är det huvudsakliga bidraget förklaringen av vibrationsöverföringsprocessen från källa till jord, det nya instrumenteringssystemet samt utvecklingen av den numeriska modellen.