| 1. |
- Peplow, Andrew T., et al.
(författare)
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Prediction and validation of traffic vibration reduction due to cement column stabilization
- 2007
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Ingår i: Soil Dynamics and Earthquake Engineering. - : Elsevier BV. - 0267-7261 .- 1879-341X. ; 27:8, s. 793-802
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Tidskriftsartikel (refereegranskat)abstract
- The transmission and reduction of vibrations in the far-field of the surface of the ground due to a surface load is investigated theoretically and validated with given field measurement data. The performance of a given stabilization column, located directly underneath the load, at a number of receiver positions is studied and-measured in terms of insertion loss. A numerical model is presented, which enables the wave-field in the region of the column to be determined, based on an integral equation formulation of the problem which is solved using a boundary element approach. It is shown that the column has a beneficial effect at low frequencies especially in certain frequency bandwidths and is validated with field data. However, when the Rayleigh wavelength becomes short compared with the depth and width of the column adverse effects occur at some frequencies which are also observed in the far-field. Various depths of columns and material properties of the surrounding soil medium are studied and results presented so that some preliminary physical conclusions may be derived.
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| 2. |
- With, Christoffer, et al.
(författare)
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Evaluation of track stiffness with a vibrator for prediction of train-induced displacement on railway embankments
- 2009
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Ingår i: Soil Dynamics and Earthquake Engineering. - : Elsevier BV. - 0267-7261 .- 1879-341X. ; 29:8, s. 1187-1197
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Tidskriftsartikel (refereegranskat)abstract
- A measuring car, the rolling stiffness measuring vehicle (RSMV), has been developed to investigate track conditions. The investigation described in this paper firstly attempts to understand whether the point flexibility of the track, i.e., the track-embankment-subsoil system, can be obtained by simultaneously measuring the force applied to an axle of the measuring car and the resulting acceleration response. Secondly, it attempts to determine the physical properties of the track by modelling it as a Bernoulli-Euler beam oil a Kelvin foundation. The final part of the paper investigates the possibility of predicting displacements on a railway embankment based oil the physical properties obtained after a train passage. Results from two sites in Sweden, Kumla and Kåhög, have been used. Investigations give encouraging results. However, as seen here, it can be difficult to analyse and obtain parameters if the resonance frequency of the system is low. The peak particle displacement of the ballast on the railway embankment was achieved with fair accuracy for both Kumla and Kåhög using the results from the accelerometer on the RSMV.
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| 3. |
- With, Christoffer, et al.
(författare)
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Prediction of train-induced vibrations inside buildings using transfer functions
- 2007
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Ingår i: Soil Dynamics and Earthquake Engineering. - : Elsevier BV. - 0267-7261 .- 1879-341X. ; 27:2, s. 93-98
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a study of the use of transfer functions to predict vibrations inside a building due to train-induced ground vibrations. It is proposed that knowing the transfer function of a building, the vibrations inside a similar building can be predicted given a known ground motion outside. A comparison has been conducted between predicted and measured vibrations inside a building in south-western Sweden due to freight and passenger trains. The transfer function was derived by using a stationary vibrating source. The average particle velocity (1 s-r.m.s.) inside the house was calculated with the transfer functions with an average error of -10%, -0.02mm/s. Prediction was achieved with a standard deviation of 23%, 0.06mm/s when no filtering of the data was used. Further work is needed to ascertain the accuracy of this method.
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| 4. |
- With, Christoffer, et al.
(författare)
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Validation of an empirical model for prediction of train-induced ground vibrations
- 2006
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Ingår i: Soil Dynamics and Earthquake Engineering. - : Elsevier BV. - 0267-7261 .- 1879-341X. ; 26, s. 983-990
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a validation of EnVib-01, an empirical model to predict train-induced ground vibrations in a preliminary design phase. The model is simple to use and gives a quick assessment of the magnitude and the distribution of the ground motion that can be expected in the vicinity of the track. It can be of use during planning of a new track or before allowing trains to run faster with heavier cargo on an existing railway line. The model has been validated from two field measurements in Sweden. The strengths and weaknesses of the model, which has shown promising results, are discussed.
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| 5. |
- With, Christoffer, et al.
(författare)
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Wave barrier of lime-cement columns against train-induced ground-borne vibrations
- 2009
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Ingår i: Soil Dynamics and Earthquake Engineering. - : Elsevier BV. - 0267-7261 .- 1879-341X. ; 29:6, s. 1027-1033
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a comparison between measured train-induced ground vibrations in the free-field before and after countermeasures had been taken at Kahog near Gothenburg in Sweden. A wave barrier of lime-cement columns was constructed parallel to the railway in order to reduce the ground-borne vibrations inside nearby buildings. On top of the barrier an embankment was built to reduce air-borne vibrations. Due to the wave barrier design, part of the energy content of the waves was expected to be reflected by the screen and transmitted energy was expected to be partly scattered. Contribution from the noise-embankment was not thought likely but could not be ruled out due to its fairly large mass and its close proximity to the railway. The effect of the mitigating measures resulted in a 67% reduction of the maximum particle velocity at 30 m and 41% at 60 m from the railway. A simple two-dimensional finite element model has been used to Study the relative importance of the wave barrier and the noise-embankment as contributors to the mitigation recorded of the ground vibrations in the field. It is concluded with respect to ground vibrations that both the barrier and the embankment had a mitigating effect but that the contribution from the barrier dominated. Furthermore, it is seen from the field results as well as the Simulation that the effect of the mitigating action is reduced with increasing distance from the railway.
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| 6. |
- Rydén, Nils, et al.
(författare)
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Analysis of surface waves from the light weight deflectometer
- 2009
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Ingår i: Soil Dynamics and Earthquake Engineering. - : Elsevier BV. - 0267-7261. ; 29:7, s. 1134-1142
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Tidskriftsartikel (refereegranskat)abstract
- The combination of high strain modulus from conventional light weight deflectometer (LWD) analysis and low strain modulus front LWD-induced seismic analysis would move the pavement community towards field characterization of non-linear soil stiffness for use in mechanistic-empirical pavement design. This paper explores the experimental and numerical analysis of surface seismic waves during conventional light weight deflectometer testing. Field experiments were conducted on clay, silt and gravel soils to characterize the nature of LWD-induced surface waves and to determine both low and high strain moduli. The usable high frequency limit was found to be 300 Hz for LWD-induced surface waves, enabling the low strain modulus Characterization of the top 0.3-0.5-m-thick soil layer. A numerical investigation revealed that modal interference is a significant contributor to near field effects, and that a distance of one wavelength between the LWD center and receiver array center is required to minimize these effects. The LWD-induced surface wave strain levels at a 1 m offset from the LWD were found to be on the order of 10(-2) to 10(-3)% compared to the 10(-3) to 10(-4)% strain levels associated with conventional small hammer-induced surface waves. The measured low and high strain modulus compares well with published modulus reduction functions. (C) 2009 Elsevier Ltd. All rights reserved.
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