Vibration isolation using open or filled trenches Part 2: 3-D homogeneous soil
ABSTRACT The isolation of structures from ground transmitted waves by open and infilled trenches in a three-dimensional context is numerically studied. The soil medium is assumed to be elastic or viscoelastic, homogeneous and isotropic. Waves generated by the harmonic motion of a surface rigid machine foundation are considered in this work. The formulation and solution of the problem is accomplished by the boundary element method in the frequency domain. The infinite space fundamental solution is used requiring discretization of the trench surface, the soil-foundation interface and some portion of the free soil surface. The proposed methodology is first tested for accuracy by solving three characteristic wave propagation problems with known solutions and then applied to several vibration isolation problems involving open and concrete infilled trenches. Three-dimensional graphic displays of the surface displacement pattern around the trenches are also presented.
Full-textDOI: · Available from: Biswajit Dasgupta, Oct 06, 2014
- SourceAvailable from: Deniz Ülgen
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- "The numerical techniques including finite element method (FEM) and boundary element method (BEM) have been widely used to understand the isolation mechanism of wave barriers. Beskos et al. , Al-Hussaini , Kattis et al. , Tsai and Chang , Wang et al , Zoccali et al. , Saikia and Das  employed numerical methods in order to evaluate the effect of both geometrical properties and type of wave barriers on screening performance. They concluded that open trenches provided better performance for vibration isolation compared to in-filled trenches. "
ABSTRACT: The isolation of ground-borne vibrations caused by heavy traffic, construction activities and railway transportation has gained importance in recent years with rapid urbanization. Open or in-filled trenches have commonly been used as wave barriers in reducing unwanted vibrations. There only few experimental data concerning the effects of frequency of excitation, soil layering, material type and dimensions of the wave barrier on vibration control and isolation. In the present study, a series of full scale field experiments were conducted in order to investigate the screening efficiency of open, water filled and geofoam filled trenches. The attenuation of ground borne vibration was examined to determine the effects of frequency, distance and complex behavior of layering and irregular geometry of soil profile. Moreover, the results obtained from the experimental tests were compared with the numerical and experimental findings available in literature. Consequently, the field tests confirmed that the geofoam filled trench can be used as an efficient isolation system for reducing the transmission of ground-borne vibrations.Construction and Building Materials 07/2015; 86. DOI:10.1016/j.conbuildmat.2015.03.098 · 2.30 Impact Factor
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- "In reference to soil-structure-interaction (SSI) problems involving buried infrastructure, we mention here the early work of Beskos et al.  and of Dasgupta et al.  on the use of either open or filled trenches for providing vibration isolation to an enclosed area, which is more often than not a foundation. In both references, the FD-BEM was used to model the trench interfaces plus the free surface, with the former and latter references respectively treating 2D and 3D trench configurations in homogeneous soil. "
ABSTRACT: In this review paper, we concentrate on the use of boundary integral equation (BIE) based methods for the numerical modeling of elastic wave motion in naturally occurring media. The main reason for using BIE is the presence of the free surface of the earth, whereby large categories of problems involve continua with a small surface to volume ratio. Given that under most circumstances, BIE require surface discretization only, substantial savings can be realized in terms of the size of the mesh resulting from the discretization procedure as compared to domain-type numerical methods. We note that this is not necessarily the case with man-made materials that have finite boundaries. Thus, although the emphasis here is on wave motion in geological media, this review is potentially of interest to researchers working in other scientific fields such as material science. Most of the material referenced in this reviews drawn from research work conducted in the last fifteen years, i.e., since the year 2000, but for reasons of completeness reference is made to seminal papers and books dating since the early 1970s. Furthermore, we include here methods other than the BIE-based ones, in order to better explain all the constituent parts of hybrid methods. These have become quite popular in recent years because they seem to combine the best features of surface-only discretization techniques with those of domain type approaches such as finite elements and finite differences. The result is a more rounded approach to the subject of elastic wave motion, which is the underlying foundation of all problems that have to do with time-dependent phenomena in solids.Soil Dynamics and Earthquake Engineering 03/2015; 70. DOI:10.1016/j.soildyn.2014.11.013 · 1.22 Impact Factor
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- "In-filled trenches using soil bentonite (Haupt 1981, Beskos et al. 1986), piles (Kattis et al. 1999), very flexible gas cushion (Massarsch 2005) may be associated with several genuine problems such as on site transportation cost, installation cost, reactivity with surrounding soil etc. Moreover, open trenches are sometime found practically infeasible from construction point of view. "
ABSTRACT: This paper presents the application of continuous geofoam filled barriers as vibration screening material. The numerical analysis is performed by using two-dimensional finite element method under dynamic condition considering vertically oscillated strip footing as a dynamic source. The present analysis considers the foundation bed as linearly elastic, isotropic, homogeneous and non-homogeneous soil deposit. The vertical displacement amplitudes of ground vibrations are measured at different pick-up points along the ground surface to determine the amplitude reduction factor, which is considered as a measure of the screening efficiency.Computer Methods and Recent Advances in Geomechanics, Kyoto, Japan; 09/2014