Use of Gas Cushions for Field Measurement and Analysis of Hybrid Vibration Isolation Wall

Kanda, Hitoshi; Ishii, Hirotoshi; Yoshioka, Osamu

doi:10.1177/0361198106198300107

Cited by 10 publications

(5 citation statements)

References 6 publications

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“…They are typically filled using a low density material (e.g. gas cushion [169] or polyurethane [170]) to increase the reflection coefficient between the soil and the trench, thus increasing its effectiveness. Essentially, the backfill should be of a low acoustic impedance compared to the background soil.…”

Section: Mitigation Of Ground Vibrationmentioning

confidence: 99%

Benchmarking railway vibrations – Track, vehicle, ground and building effects

Connolly

Kouroussis

Laghrouche

et al. 2015

Construction and Building Materials

219

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This paper reviews, synthesises and benchmarks new understandings relating to railway vibrations. Firstly, the effect of vibrations on passenger comfort is evaluated, followed by its effect on track performance. Then ground-borne vibration is discussed along with its effect on the structural response of buildings near railway lines. There is discussion of the most suitable mathematical and numerical modelling strategies for railway vibration simulation, along with mitigation strategies. Regarding ground borne vibration, structural amplification is discussed and how vibration mitigation strategies can be implemented. There is also a focus on determining how 'critical velocity' and 'track critical velocity' are evaluated-with the aim of providing clear design guidelines related to Rayleigh wave velocity. To aid this, conventional site investigation data is reviewed and related to critical velocity calculations. The aim is to provide new thinking on how to predict critical velocity from readily available conventional site investigation data.

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Section: Mitigation Of Ground Vibrationmentioning

confidence: 99%

Benchmarking railway vibrations – Track, vehicle, ground and building effects

Connolly

Kouroussis

Laghrouche

et al. 2015

Construction and Building Materials

219

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“…This is physically impractical as trenches require in-fill material for safety and stability criteria. A common engineering solution is to fill trenches with low density gas cushions [34] or polyurethane [13]. Rather than introduce additional approximations for in-fill material properties it was found that open trenches provided an effective condition under which to analyze trench geometry.…”

Section: Trench Modellingmentioning

confidence: 99%

Optimising low acoustic impedance back-fill material wave barrier dimensions to shield structures from ground borne high speed rail vibrations

Connolly

Giannopoulos

Fan

et al. 2013

Construction and Building Materials

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Ground borne vibrations generated due to high speed train passage can cause undesirable effects on the nearby environment. One approach to mitigate vibration levels is to use "wave barriers", however their installation cost may be very high. In an attempt to minimize construction costs, numerical modelling and physical experiments are performed to determine guidelines for the optimisation of trench dimensions. Substantial savings are found to be achievable through carefully chosen barrier dimensions. Firstly, for the purposes of testing a numerical model that can be used by railway wave barrier designers, a geophysical investigation is undertaken on a high speed railway line outside Edinburgh, Scotland. The testing schedule consists of vibration measurements adjacent to the line and a multi-channel analysis of surface waves technique to determine the underlying soil properties. An outline is then presented describing a newly developed three dimensional finite element railway model using commercially available software. The resulting model is modified to replicate the track and soil properties at the test site and then it is shown that the model results exhibit a strong correlation in comparison to those collected during the experimental stage. The numerical model is then used to assess the ability of a range of wave barrier configurations to protect nearby sites from railway vibration. It is found that depth and length have a strong influence on the mitigation of vibration levels but the effect of trench width is negligible. Lastly, for a specific example it is shown that cost savings of 95% are achievable if trench dimensions are carefully planned. All of the analyses require that the ratio of the acoustic impedance of soil compared to wave barrier backfill material must be greater than eight.

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“…In order to approach amplitude reduction ratio provided by open trenches, different in-filled material has been tested. In particular, in [9][10][11] geofoam (expanded polystyrene or extrude polystyrene) as in-filled materials has been studied, while in [12,13] the use of gas cushions trenches as wave barriers is analyzed, obtaining results very close to open trenches performances.…”

Section: Introductionmentioning

confidence: 99%