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| 2. |
- With, Christoffer, et al.
(författare)
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A methodology for mapping of quick clay in Sweden
- 2022
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Ingår i: Natural Hazards. - : Springer Nature. - 0921-030X .- 1573-0840. ; 112:3, s. 2549-2576
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Tidskriftsartikel (refereegranskat)abstract
- Landslides may cause severe destruction that affects both the individuals and functions vital for society. Minor landslides in an area with quick clay may trigger secondary slides, influencing a much greater area compared to slides in areas with no quick clay. Today's expanding societies demand new areas for exploitation. To effectively meet this demand, there is an increased need to identify areas where quick clay may occur. Direct or indirect methods for assessing the presence of quick clay have previously been presented as well as a strategy for site investigations in quick clay areas. In this article, a methodology for mapping quick clays for the Swedish conditions with methods commonly available in this area is presented. The methodology presented in the article is structured in steps with different levels of detail and visualized with two conceptual flowcharts. Depending on the stage of planning, different types of surveys are recommended. The methodology has been applied at four sites where integrated interpretation of airborne and ground geophysical measurements as well as geotechnical investigations have been carried out. The results from two of these sites are presented here. The study reveals that all the methods used have their advantages and limitations. However, a combined use of the information provides much more accurate interpretation that can be used for a more cost-effective future planning and decision-making.
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| 3. |
- With, Christoffer, et al.
(författare)
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Deriving parameters of track and subsoil with a stiffness measurement vehicle
- 2007
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Ingår i: Proceedings Of The 3rd International Symposium On Environment Vibrations. - 9789860118506 ; , s. 474-479
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Konferensbidrag (refereegranskat)abstract
- High speed trains and heavy loaded freight trains can induce strong shaking in track and ground in vicinity of a railway line. Excessive vibration levels in embankment and ground could give rise to serious problems. increasing speed and axle load is causing a growing concern for the authorities. In Sweden, a special measuring car, RSMV, has been developed to investigate the condition of the tracks. The aspect that recently has been put under investigation is if, by simultaneous measurements of an applied force to an axle and its acceleration response, the point flexibility of the track system, can be modeled by a BEK-system. This paper describes the method of derivation of parameters and present results from one site.
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| 4. |
- 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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| 5. |
- With, Christoffer, et al.
(författare)
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Field test of a semi-empirical model for prediction of train-induced ground vibration
- 2005
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Ingår i: Environmental Vibrations. - 0415390354 ; , s. 351-355
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Konferensbidrag (refereegranskat)abstract
- This paper presents a field test of the semi-empirical model ENVIB-01 in predicting train-induced ground vibrations. The model is meant to be used in an early design phase when the major concern is to locate areas with heightening risk of excessive ground motion or before allowing operators to increase speed and/or load. ENVIB-01 is easy to use and can quickly produce prediction of ground motion at the railway embankment and in the vicinity of the track. Measurements at one site are here presented and the results from the embankment and at distances of up to 30 m from the track are compared to a prediction achieved with the model.
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| 6. |
- With, Christoffer, et al.
(författare)
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Identification of effective properties of the railway substructure in the low-frequency range using a heavy oscillating unit on the track
- 2010
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Ingår i: Archive of applied mechanics (1991). - : Springer Science and Business Media LLC. - 0939-1533 .- 1432-0681. ; 80:9, s. 959-968
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Tidskriftsartikel (refereegranskat)abstract
- As the demand for predictions of train-induced vibrations is increasing, it is essential that adequate parameters of the railway structure are given as input in the predictions. Gathering this information can be quite time-consuming and costly, especially when predictions are required for the low-frequency emission. This article presents a procedure for deriving the effective properties of the foundation under the sleepers of a railway track from measurements taken with a heavy oscillating unit on the track. The unit consists of two masses inside a modified freight car that exert a dynamic force in the range 3-30 Hz on one of the two axles. The ratio of force applied on the axle over the resulting response measured with an accelerometer is studied. The foundation of the sleepers is modelled using a frequency-dependent complex-valued dynamic stiffness.
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| 9. |
- 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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