scholarly journals Vibration Isolation of a Rubber-Concrete Alternating Superposition In-Filled Trench for Train-Induced Environmental Vibration Based on 2.5D Indirect Boundary Element Method

2021 ◽  
Vol 9 ◽  
Author(s):  
Liguo Jin ◽  
Jingya Wang ◽  
Xujin Liu ◽  
Qiangqiang Li ◽  
Zhenghua Zhou
Keyword(s):  
Elastic Waves ◽  
High Speed ◽  
Vibration Isolation ◽  
Soft Soil ◽  
Low Frequency ◽  
Isolation Effect ◽  
High Speed Train ◽  
Frequency Range ◽  
The Impact ◽  
Rubber Concrete

A new train-induced vibration isolation measure of rubber-concrete alternating superposition in-filled trench is presented in this paper. For analyzing the vibration isolation effect of the new measure, this paper establishes a 2.5D train-track-layered foundation-filled trench model to analyze the dynamics of track and layered foundation with the in-filled trench. The correctness of the model is verified by using the measured data of the Sweden X-2000 high-speed train. The vibration isolation effect of the rubber-concrete alternating superposition in-filled trench is calculated by using the actual soft soil foundation parameters of the X-2000 high-speed train, and the vibration isolation effect is also compared with that of the empty trench, rubber in-filled trench, and concrete in-filled trench. The results show that the vibration isolation effect of the rubber-concrete alternating superposition in-filled trench proposed in this paper is better than that of the C30 concrete in-filled trench, especially the impact on displacement. Compared with low-frequency vibrations generated by the lower train speed, the rubber-concrete alternating superposition in-filled trench has a better vibration isolation effect on high-frequency vibrations caused by higher-speed trains. The rubber-concrete alternately superposition in-filled trench has the frequency band characteristics of elastic waves. Elastic waves in the passband frequency range can propagate without attenuation, while the elastic waves in the forbidden frequency range will be filtered out.

Analysis on the Impact of the Constitutive Model of Trains Vibration in Shield Tunnel

2014 ◽  
Vol 501-504 ◽  
pp. 1787-1791
Author(s):  
Xiao Juan Quan ◽  
Xin Ming Guo ◽  
Kai Shi
Keyword(s):  
Constitutive Model ◽  
High Speed ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soft Soil ◽  
Shield Tunnel ◽  
High Speed Train ◽  
Engineering Project ◽  
Geological Conditions ◽  
The Impact

In this paper, with the in-situ engineering project Shiziyang tunnel of Guangzhou-Shenzhen Railway, under the disturbance of high-speed train vibration load, the shield tunnels dynamic response and foundations sand liquefying phenomenon are studied ,where they are mainly located in saturated and soft soil. Due to the tunnel going through the paralic deposited silt layer, silty soil, alluvial clay layer and the layer of fine sand or coarse sand layer, under the condition that enduring a long time of high-speed train running, which may easily lead to the foundation liquefaction and asymmetric settlement. At the entrance of the tunnel, with the poor geological conditions and weak cladding, which can easily induce sliding and collapse, where the geological conditions of this part is the most unfavorable place. Through numerical simulations, the main factor the constitutive model is explored, which may affect the single high-speed train loads on the vibration response of the train in shield tunnel and the law of accumulation and dissipation for pore water pressure.

Active Attenuation of Low Frequency Noise Radiated from Tunnel Exit of High Speed Train

1994 ◽  
Vol 13 (2) ◽  
pp. 39-47
Author(s):  
Min Liang ◽  
Toshiya Kitamura ◽  
Katsushi Matsubayashi ◽  
Toshifumi Kosaka ◽  
Tatsuo Maeda ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Pressure Wave ◽  
High Speed ◽  
Outer Space ◽  
Low Frequency ◽  
Close Relation ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Active Cancellation

A pressure wave occurs at the instant when a high speed train enters into a long tunnel. The wave propagates downstream to the tunnel exit and low frequency noise is radiated from the exit to outer space. The low frequency noise causes a lot of problems1 to the residents living near the exit and has a close relation with the pressure gradient of the pressure wave. To attenuate the low frequency noise, an active cancellation system rather than a passive one is developed. This research uses a model tunnel to examine the characteristic of the pressure wave and investigates the possibility to reduce the low frequency noise by reducing the pressure wave gradient with active cancellation.

scholarly journals A new era for low frequency Galactic center transient monitoring

2013 ◽  
Vol 9 (S303) ◽  
pp. 458-460
Author(s):  
N. E. Kassim ◽  
S. D. Hyman ◽  
H. Intema ◽  
T. J. W. Lazio
Keyword(s):  
Radio Astronomy ◽  
Galactic Center ◽  
Monitoring Program ◽  
Low Frequency ◽  
Frequency Range ◽  
New Era ◽  
The Impact ◽  
New System

AbstractAn upgrade of the low frequency observing system of the VLA developed by NRL and NRAO, called low band (LB), will open a new era of Galactic center (GC) transient monitoring. Our previous searches using the VLA and GMRT have revealed a modest number of radio-selected transients, but have been severely sensitivity and observing time limited. The new LB system, currently accessing the 236--492 MHz frequency range, promises ≥5 × improved sensitivity over the legacy VLA system. The new system is emerging from commissioning in time to catch any enhanced sub-GHz emission from the G2 cloud event, and we review existing limits based on recent observations. We also describe a proposed 24/7 commensal system, called the LOw Band Observatory (LOBO). LOBO offers over 100 VLA GC monitoring hours per year, possibly revealing new transients and helping validate ASTRO2010's anticipation of a new era of transient radio astronomy. A funded LOBO pathfinder called the VLA Low Frequency Ionosphere and Transient Experiment (VLITE) is under development. Finally, we consider the impact of LB and LOBO on our GC monitoring program.

scholarly journals Vibration Isolation of Existing Buildings in Microvibration Traffic Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Qian Xia ◽  
Wen-jun Qu ◽  
Yi-qing Li ◽  
Jin Zhao
Keyword(s):  
Vibration Isolation ◽  
Theoretical Calculations ◽  
Residential Buildings ◽  
Isolation Effect ◽  
Slab Thickness ◽  
Filling Material ◽  
Construction Technology ◽  
Existing Buildings ◽  
Isolation System ◽  
The Impact

In order to explore the impact of traffic environmental microvibration on buildings, this paper studies indoor vibration isolation, a method applicable to existing buildings. The vibration isolation scheme is designed based on the residential buildings adjacent to metro lines in Shanghai. By using the dynamic theory, the effective range of vibration isolation stiffness is analyzed. The effectiveness of the indoor vibration isolation method is verified through theoretical calculations and comparison of field measurements before and after isolation. A detailed numerical model is established to analyze the indoor isolation and the effect after parameter optimization from the slab thickness, filling material, and isolator stiffness. The results show that the isolation effect is proportional to the thickness of the total slab thickness of the isolation system and inversely proportional to the stiffness of the isolator. And when concrete is used as the filling material, the isolation effect is best. The isolation effect of the midspan position is better than that of the wall-floor junction. The vibration isolation effect is more obvious after the parameters are optimized. With its convenient construction technology, short cycle, and low cost, this method is worth promoting.

scholarly journals The Effect of Pendolino high-speed rail on the structure of buildings located in the proximity of railway tracks

2016 ◽  
Vol 21 (1) ◽  
pp. 231-238
Author(s):  
K. Grębowski ◽  
Z. Ulman
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Building Structure ◽  
High Speed Train ◽  
High Speed Rail ◽  
Railway Tracks ◽  
High Speed Trains ◽  
Railway System ◽  
The Subject ◽  
The Impact

Abstract The following research focuses on the dynamic analysis of impact of the high-speed train induced vibrations on the structures located near railway tracks. The office complex chosen as the subject of calculations is located in the northern part of Poland, in Gdańsk, in the proximity of Pendolino, the high speed train route. The high speed trains are the response for the growing needs for a more efficient railway system. However, with a higher speed of the train, the railway induced vibrations might cause more harmful resonance in the structures of the nearby buildings. The damage severity depends on many factors such as the duration of said resonance and the presence of additional loads. The studies and analyses helped to determinate the method of evaluating the impact of railway induced vibrations on any building structure. The dynamic analysis presented in the research is an example of a method which allows an effective calculation of the impact of vibrations via SOFISTIK program.

Study of Low Frequency Noise Occurred from Tunnel Entrance of High Speed Train

2001 ◽  
Vol 2001.11 (0) ◽  
pp. 120-122
Author(s):  
Toshiya KITAMURA ◽  
Yasuhiko OKAWA ◽  
Toshikazu KATO ◽  
Shinji YAMADA
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Frequency Noise ◽  
High Speed Train ◽  
Low Frequency Noise ◽  
Tunnel Entrance
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