• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.357-363
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• 2009

In this paper, field measurements in the subway tunnel and adjacent building were performed to predict the pound vibration level induced by urban rapid transit (subway) in Seoul, Korea. From the results of the measurements, the measured ground vibration level induced by subway in Seoul is smaller than the empirical formula of New York, but it is bigger than the empirical formula of Tokyo which has been commonly used in Korea. We suggested the empirical formula for prediction of ground vibration level induced by subway in Seoul considering on the wave propagation path for soils or rocks, respectively.

• Geomechanics and Engineering
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• v.30 no.3
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• pp.273-280
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• 2022

A certain amount of random vibration excitation to subway track is caused by subway operation. This excitation is transmitted through track foundation, tunnel, soil medium, and ground building to the ground and ground structure, causing vibration. The vibration affects ground building. In this study, the results of ANSYS numerical simulation was used to establish back-propagation (BP) neural network model. Moreover, a back-propagation neural network model consisting of five input neurons, one hidden layer, 11 hidden-layer neurons, and three output neurons was used to analyze and calculate the vertical Z-vibration level of New Capital's ground buildings of Qingdao Metro phase I Project (Line M3). The Z-vibration level under different working conditions was calculated from monolithic roadbed, steel-spring floating slab roadbed, and rubber-pad floating slab roadbed under the working condition of center point of 0-100 m. The steel-spring floating slab roadbed was used in the New Capital area to monitor the subway operation vibration in this area. Comparing the monitoring and prediction results, it was found that the prediction results have a good linear relationship with lower error. The research results have good reference and guiding significance for predicting vibration caused by subway operation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1287-1292
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• 2001

Subway train-induced ground-borne vibration is studied. Previously used vibration level prediction equations are reviewed. Measured vibration levels are compared with the predicted results and numerically computed results. The results show that vibration level does not decrease proportionally with the distance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.738-742
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• 2005

Ground vibration at Gil-dong in Seoul induced by the 5th ling of Seoul Subway is predicted using various prediction methods and compared with measured vibration. Also, several issues on the improvement of prediction methods are discussed. Furthermore, as an alternative vibration source, measured vibration acceleration level(VAL) on the tunnel wall of the Bundang line of Seoul Subway is applied to the prediction of the VAL at the location mentioned previously. Then requirements accompanied to the suggestion of the new vibration source appropriate to the condition of Seoul Subway.

• Smart Structures and Systems
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• v.19 no.1
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• pp.1-10
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• 2017

The operation of subway trains induces secondary structure-borne vibrations in the nearby underground spaces. The vibration, along with the associated noise, can cause annoyance and adverse physical, physiological, and psychological effects on humans in dense urban environments. Traditional tethered instruments restrict the rapid measurement and assessment on such vibration effect. This paper presents a novel approach for Wireless Smart Sensor (WSS)-based autonomous evaluation system for the subway train-induced vibrations. The system was implemented on a MEMSIC's Imote2 platform, using a SHM-H high-sensitivity accelerometer board stacked on top. A new embedded application VibrationLevelCalculation, which determines the International Organization for Standardization defined weighted acceleration level, was added into the Illinois Structural Health Monitoring Project Service Toolsuite. The system was verified in a large underground space, where a nearby subway station is a good source of ground excitation caused by the running subway trains. Using an on-board processor, each sensor calculated the distribution of vibration levels within the testing zone, and sent the distribution of vibration level by radio to display it on the central server. Also, the raw time-histories and frequency spectrum were retrieved from the WSS leaf nodes. Subsequently, spectral vibration levels in the one-third octave band, characterizing the vibrating influence of different frequency components on human bodies, was also calculated from each sensor node. Experimental validation demonstrates that the proposed system is efficient for autonomously evaluating the subway train-induced ambient vibration of underground spaces, and the system holds the potential of greatly reducing the laboring of dynamic field testing.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.631-640
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• 2009

In this paper, Numerical analysis was conducted to study on the reduction of ground vibration level induced by subway train. The analytical results indicated that the soil properties were the predominant factor affecting the ground vibration when the tunnel was located in the soil layer. On the other hand, the rock properties were the predominant one when the tunnel was located in the rock layer. The effects of the angle between the vertical line of vibration source and the receive point on the reduction of vibration level were also evaluated. There were little difference in the reduction of vibration level when the receive point was located within $30^{\circ}$. The vibration level, however, rapidly decreased when the angle between the two points was larger than $40^{\circ}$.

• Journal of KSNVE
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• v.7 no.5
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• pp.789-796
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• 1997

In this study a conventional rubber mount and a new form of base isolator made of steel spring coated with natural and articial rubber were manufactured and tested on a shaking table to investigate the capacity of reducing the vertical vibration of a building induced by subway train. The model structure used in the test is a 1/4 scaled steel structure, and a white noise input and train vibration records were used to check the effectiveness of the isolators. According to the results all three types of isolators turned out to perform effectively in reducing the acceleration and the natural rubber-coated one is ranked best among the isolators. However the vertical displacement of the model is increased due to the instolation of the bearings, and the safty against the lateral load induced by earthquake ground motion should be provided to be able to apply the system to the real buildings.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.3
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• pp.175-184
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• 2004

Ground-borne noise and vibration generated by underground transit system has been recognized as an important environmental problem. This study reviews several of the procedures that have been used to predict ground-borne vibration. The vibration responses are measured at three sites that have different soil qualities. The measured vibration levels are compared with the predicted results by previously used vibration level prediction models. There are some drawbacks to apply these prediction models to selected sites because most of the existing prediction models are primarily based on empirical data and all of them lack of analytical models for the mechanism of ground-borne vibration generation. radiation, and propagation. In this study a numerical method, which is based on explicit differential method, is used to compensate for the shortcomings of existing prediction models. Although numerically computed results are not quantitatively in good agreement with the measured results, the trends are comparable in the sense that vibration level does not decrease monotonically with distance. Also, the site with the deepest tunnel gives the highest vibration level.

• Journal of KSNVE
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• v.7 no.2
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• pp.293-300
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• 1997

Noise and vibration induced by subway operation is one of the major problem for the residents living nearby railway tracks. Many scientists and engineers have been working on proposing the more accurate prediction equation of noise and vibration to provide the better residential environment. Some predictiction equations were determined to compare the measurement value of a noise obtained from the inside of a residential area. It was observed that the condition of a soil type is one of the major parameter which should be considered to obtain the more accurate prediction value of a noise.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.597-602
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• 2002

This study reviews several of the procedures that have been used to predict ground-born vibration. The vibration responses are measured at three sites that have different soil qualities. The measured vibration levels are compared with the predicted results by previously used vibration level prediction models. In this study a numerical method, which is based on explicit differential method, is used to compensate tot existing prediction models. Although numerically computed results are not quantitatively in good agreement with the measured results, the trends are comparable in the sense that vibration level does not decrease monotonically with distance. Also, The site with the deepest tunnel gives the highest vibration level.