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1.
An analytical procedure is presented for determining groundborne vibrations in buildings due to subway trains. The procedure involves a finite element idealization of the subway-soil-structure interaction problem, using an analytical model for the train loading spectrum at the tunnel invert. Both direct fixation and floating slab track support systems are considered. The train model is verified using the measurements of rail velocities. The proposed procedure is applied to the case of a four-storey podium block enclosing twin double-box subways within the confines of its ribbed wall foundations. The severity of velocity response levels of the building, in relation to vibration standards, is also considered. 相似文献
2.
This paper outlines a vibration prediction tool, ScopeRail, capable of predicting in-door noise and vibration, within structures in close proximity to high speed railway lines. The tool is designed to rapidly predict vibration levels over large track distances, while using historical soil information to increase accuracy. Model results are compared to an alternative, commonly used, scoping model and it is found that ScopeRail offers higher accuracy predictions. This increased accuracy can potentially reduce the cost of vibration environmental impact assessments for new high speed rail lines.To develop the tool, a three-dimensional finite element model is first outlined capable of simulating vibration generation and propagation from high speed rail lines. A vast array of model permutations are computed to assess the effect of each input parameter on absolute ground vibration levels. These relations are analysed using a machine learning approach, resulting in a model that can instantly predict ground vibration levels in the presence of different train speeds and soil profiles. Then a collection of empirical factors are coupled with the model to allow for the prediction of structural vibration and in-door noise in buildings located near high speed lines. Additional factors are also used to enable the prediction of vibrations in the presence of abatement measures (e.g. ballast mats and floating slab tracks) and additional excitation mechanisms (e.g. wheelflats and switches/crossings). 相似文献
3.
There is concern regarding the long-term vibration effects caused by metro trains on historic buildings. In this paper, the impact of metro train-induced vibrations on the Bell Tower in Xi’an above two spatially overlapping tunnels was studied.Metro Line 2 has been operational since 2011, and Line 6 is still under construction. To study and control the effect of micro vibrations on the Bell Tower, a metro train–track–tunnel–soil 3D dynamic FE model was developed. The vibration response generated by Line 2 was then predicted, and the influences of train speed on ground vibration were analysed. In addition, a detailed in situ measurement, which helped calibrate the numerical model and determine the dynamic behaviour of timber structures, was performed. Finally, the calibrated models and measured results were used to predict vibrations caused by road traffic and trains from two spatially overlapping metro lines. This was performed under different route schemes and train operation conditions.The results showed that installing steel spring floating slab tracks (FST) and decreasing train speeds had obvious effects on controlling the ground peak particle velocity (PPV). Simulated results from both the input impulse and output response generated by metro Line 2 matched well with actual measurements. If correct designs are employed, it is possible to resolve the vibration problem on historic buildings caused by metro trains. 相似文献
4.
In this paper, a numerical approach for the prediction of vibrations induced in buildings due to railway traffic in tunnel is proposed. The numerical method is based on a sub-structuring approach, where the train is simulated by a multi-body model; the track–tunnel–ground system is modeled by a 2.5D FEM–PML approach; and the building by resource to a 3D FEM method. The coupling of the building to the ground is established taking into account the soil–structure-interaction (SSI). The methodology proposed allows dealing with the three-dimensional characteristics of the problem with a reasonable computational effort. Using the proposed model, a numerical study is developed in order to better discern the impact of the use of floating slabs systems for the isolation of vibrations in the tunnel on the dynamic response of a building located in the surrounding of the tunnel. The comparison between isolated and non-isolated scenarios allowed concluding that the mats stiffness is a key parameter on the efficiency of floating slab systems. Furthermore, it was found that the selection of the stiffness of the mats should be performed carefully in order to avoid amplification of vertical vibrations of the slabs of the building. 相似文献
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以黄韩侯铁路新黄河特大桥156m简支钢桁梁桥作为工程背景,建立车辆动力模型、桥梁有限元模型并考虑轮轨关系,以蛇形运动和轨道不平顺作为系统的自激激励源,利用大型有限元软件ANSYS以及UM(Universal Mechanism)动力学分析软件联合进行仿真分析。从桥梁结构的桥门架、宽跨比、曲线钢桁梁桥和车辆系统的轨道不平顺以及货车编组角度出发,研究大跨度简支钢桁梁桥车-桥耦合振动的影响因素。经过计算分析得出:钢桁梁桥桥门架对桥梁跨中加速度影响较大;曲线钢桁梁桥随着线路半径的增大,各车辆动力响应参数逐渐变小,轮轨力受到影响;钢桁梁桥宽跨比的增加使得横向刚度随之增加,桥梁横向振动变小;各项车辆动力响应均随着轨道情况变差而总体呈现逐渐增大趋势,车辆安全性、舒适性和平稳性指标逐渐变差;全列空车编组和空重混编对钢桁梁车-桥耦合系统是不利的编组形式,实际情况中应该避免。 相似文献
6.
R. Paolucci A. Maffeis L. Scandella M. Stupazzini M. Vanini 《Soil Dynamics and Earthquake Engineering》2003,23(6):425-433
The ground vibrations induced by a passenger train at the test site of Ledsgaard, Sweden, have been analysed and numerically simulated through a spectral element discretization of the soil. To calculate the spatial distribution of loading due to train passage, the train is decoupled from the track, and a suitable series of static forces is applied. The track and the embankment are modeled as a beam on elastic foundation, using analytical solutions for loads moving at constant velocity. The results of both 2D and 3D modelling assumptions are thoroughly discussed, in terms of prediction of track motion and of attenuation of peak ground velocity with distance. 相似文献
7.
A simplified analytical model including the coupled effects of the wheel–rail–soil system and geometric irregularities of the track is proposed for evaluation of the moving train load. The wheel–rail–soil system is simulated as a series of moving point loads on an Euler–Bernoulli beam resting on a visco-elastic half-space, and the wave-number transform is adopted to derive the 2.5D finite element formulation. The numerical model is validated by published data in the literature. Numerical predictions of ground vibrations by using the proposed method are conducted at a site on the Qin-Shen Line in China. 相似文献
8.
This paper presents a comprehensive experimental campaign developed on a stretch of the Portuguese railway network. The experimental work includes three fundamental and complementary components: the characterization of the ground, the characterization of the track and the measurement of the vibrations generated by railway traffic. The characterization of the ground was performed using a combination of conventional and geophysical tests (cross-hole and SASW). The mechanical characterization of the track was performed through receptance tests and the rail unevenness profile was accurately measured. The vibrations due to the passage of more than 20 trains were measured. First, a selection of the results is presented and analysed in detail; later, the variability of the responses is briefly discussed. The presented data may be used by other researchers (e.g. in the validation of their prediction models), since it can be downloaded from www.fe.up.pt/~csf/DataCarregado.zip. 相似文献
9.
This work presents an efficient methodology for the analysis of vibrations in a railroad track system, induced by the passage of conventional and high-speed trains. To this end the Boundary Element Method is used to model the soil-tie system within the framework of impulse response techniques. Conventional Finite Element Methods along with Newmark's integration is used for the modeling of the rail system. The two methods are coupled at the tie-rail interface and the solution is obtained following a staggered, time marching scheme in an efficient manner. The methodology accounts for Soil-Structure Interaction and traveling wave effects. In addition, this work identifies the parameters that affect the efficient modeling of railroad track systems as they pertain to the proposed solution methodology. 相似文献
10.
This paper outlines an experimental analysis of ground-borne vibration levels generated by high speed rail lines on various earthwork profiles (at-grade, embankment, cutting and overpass). It also serves to provide access to a dataset of experimental measurements, freely available for download by other researchers working in the area of railway vibration (e.g. for further investigation and/or the validation of vibration prediction models).First, the work outlines experimental investigations undertaken on the Belgian high speed rail network to investigate the vibration propagation characteristics of three different embankment conditions. The sites consist of a 5.5 m high embankment, an at-grade section and a 7.2 m deep cutting. The soil material properties of each site are determined using a ‘Multichannel Analysis of Surface Waves’ technique and verified using refraction analysis. It is shown that all sites have relatively similar material properties thus enabling a generalised comparison.Vibration levels are measured in three directions, up to 100 m from the track due to three different train types (Eurostar, TGV and Thalys) and then analysed statistically. It is found that contrary to commonly accepted theory, vertical vibrations are not always the most dominant, and that horizontal vibrations should also be considered, particularly at larger offsets. It is also found that the embankment earthworks profile produced the lowest vibration levels and the cutting produced the highest. Furthermore, a low (positive) correlation between train speed and vibration levels was found. A selection of the results can be downloaded from www.davidpconnolly.com. 相似文献
11.
Dynamic analysis of slab track on multi-layered transversely isotropic saturated soils subjected to train loads 总被引：1，自引：0，他引：1
The dynamic responses of a slab track on transversely isotropic saturated soils subjected to moving train loads are investigated by a semi-analytical approach. The track model is described as an upper Euler beam to simulate the rails and a lower Euler beam to model the slab. Rail pads between the rails and slab are represented by a continuous layer of springs and dashpots. A series of point loads are formulated to describe the moving train loads. The governing equations of track-ground systems are solved using the double Fourier transform, and the dynamic responses in the time domain are obtained by the inverse Fourier transform. The results show that a train load with high velocity will generate a larger response in transversely isotropic saturated soil than the lower velocity load, and special attention should be paid on the pore pressure in the vicinity of the ground surface. The anisotropic parameters of a surface soil layer will have greater influence on the displacement and excess pore water pressure than those of the subsoil layer. The traditional design method taking ground soil as homogeneous isotropic soil is unsafe for the case of RE 1 and RG 1, so a transversely isotropic foundation model is of great significance to the design for high train velocities. 相似文献
12.
This paper explores dynamic soil–bridge interaction in high speed railway lines. The analysis was conducted using a general and fully three-dimensional multi-body finite element–boundary element model formulated in the time domain to predict vibrations caused by trains passing over the bridge. The vehicle was modelled as a multi-body system, the track and the bridge were modelled using finite elements and the soil was considered as a half-space by the boundary element method. The dynamic response of bridges to vehicle passage is usually studied using moving force and moving mass models. However, the multi-body system allows to consider the quasi-static and dynamic excitation mechanisms. Soil–structure interaction was taken into account by coupling finite elements and boundary elements. The paper presents the results obtained for a simply supported short span bridge in a resonant regime under different soil stiffness conditions. 相似文献
13.
Train viaduct behavior and nearby ground motion under the high-speed train passage have been studied in this paper. First, the findings from the field measurement alongside the high-speed Shinkansen railway in Japan are interpreted. Then, the computer simulation is made based on the soil-foundation-viaduct interaction analysis under moving axle loads. The solution method is to apply the dynamic substructure method in the frequency domain. The viaduct girders including track structure and pier supports are modeled by the three-dimensional beam-column elements. The supporting pile foundation and nearby field are discretized by the axisymmetric three-dimensional finite elements and analyzed in a semi-analytical way, with a transmitting boundary replacing the far field based on the thin layer element method. Nearby ground motion during train passage on a viaduct have been calculated by superimposing the effects from neighboring pile foundations.The main parameters affecting viaduct vibrations are discussed by taking environmental vibration into consideration. The nearby ground motion along the viaduct is recomputed by applying the above determined forces to the foundation tops. The results from numerical studies are compared with the field test data, thus proving the present simulation to be effective and reliable. 相似文献
14.
This study investigates the behavior of ground vibrations induced by trains moving on embankments using theoretical formulations, finite element analyses, and field experiments. The train-induced vibrations are large at the dominant frequencies of nV/Lc, even though the rail is very rough, where n is a positive integer, V is the train speed, and Lc is the carriage interval. For subsonic train speeds, the train-induced ground vibration is extremely small when the rail is perfectly smooth, but with a minor rail irregularity, the train-induced ground vibration can be significantly increased. However, for supersonic train speeds, the ground vibrations with or without rail irregularities are not very different, and the vibration of the first dominant frequency having the longest wavelength is the most obvious wave. 相似文献
15.
Field experiment of subgrade vibration induced by passing train in a seasonally frozen region of Daqing 总被引：1，自引：1，他引：0
Ling Xianzhang Zhang Feng Zhu Zhanyuan Ding Lin Hu Qingli . School of Civil Engineering Harbin Institute of Technology Harbin China . Institute of Subgrade Prevention Engineering China . Information & Engineering Technology College Sichuan Agricultural University Ya’an China . School of Architectural Engineering Heilongjiang University Harbin China Professor PhD Associate Professor 《地震工程与工程振动(英文版)》2009,8(1):149-157
The vibration characteristics and attenuation of the subgrade caused by passing trains in a seasonally frozen region of Daqing, China are investigated. Three field experiments were conducted during different times through the year, in normal, freezing and thawing periods, respectively, and the influence of the season, train speed and train type, is described in this paper. The results show that: (l) the vertical component is the greatest among the three components of the measured vibration near the rail track, and as the distance to the railway track increases, the dominant vibration depends on the season. (2) Compared with the vibration in the normal period, the vertical and longitudinal vibrations increase while the lateral vibration decreases in the freezing period. However, in the thawing period, the vertical and longitudinal vibrations decrease, and the lateral vibration increases. (3) As train speeds increase, the subgrade vibration increases. (4) The vibration induced by a freight train is greater than by a passenger train. These observations provide a better understanding of the vibration and dynamic stability of the subgrade and may be useful in developing criteria for railway and building construction in cold regions. 相似文献
16.
Diagnosis and prediction of vibration from railway trains 总被引：7，自引：0，他引：7
In the North West of France, more particularly in the region of the Somme Bay, where the ground is constituted mainly of peat, observation of the surface of the soil near railway tracks has revealed high levels of displacement. This paper, contains a prediction model and diagnosis of vibration near the track. A model of a railway track on layered ground subjected to a moving train has been built and the calculation method uses Fourier transform formalism for a semi-analytical solution in the wave number domain. It includes all elements of the track and allows a parametric analysis of its different elements and evaluation of vertical displacement according to the speed, weight and composition of each train. The diagnosis has been performed with in situ measurements and with the aim of the validation of the model. A parameter study of the ground undertaken by seismic measurements shows a critical speed close to 100 m/s while the studied trains are moving with sub-Rayleigh speeds. Measurements give us a lot of information about lateral and vertical acceleration on the soil's surface and parts of the track. For high speeds and freight trains, displacement reaches more than 10 mm. 相似文献
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This paper has two main purposes. One is to present and analyse soil and structural vibration data obtained experimentally during certification testing of the high-speed train line between Córdoba and Málaga (Spain) that was opened on December 2007. The second is to show the capabilities of a three-dimensional boundary element method (BEM)/finite element method (FEM) numerical approach for the analysis of train induced vibrations. The model can represent local soil conditions, discontinuities such as underpasses, as well as structures placed next to the rail track. Vibrations in those structures can be computed taking into account, in a rigorous way, dynamic soil–structure interaction and local soil properties. Experimental and numerical results at several points near the track are compared. Results for an overhead contact support structure are also evaluated. The comparison of numerically predicted and recorded results shows that the model is reliable for predicting the amplitude of vibrations produced in the soil and nearby structures by high-speed trains. 相似文献
20.
Model testing in laboratory, as an effective alternative to field measurement, provides valuable data to understand railway׳s dynamic behaviors under train moving loads. This paper presents comprehensive experimental results on track vibration and soil response of a ballastless high-speed railway from a full-scale model testing with simulated train moving loads at various speeds. A portion of a realistic ballastless railway comprising slab track, roadbed, subgrade, and subsoil was constructed in a larger steel box. A computer-controlled sequential loading system was developed to generate equivalent vertical loadings at the track structure for simulating the dynamic excitations due to train׳s movements. Comparisons with the field measurements show that the proposed model testing can accurately reproduce dynamic behaviors of the track structure and underlying soils under train moving loads. The attenuation characteristics of dynamic soil stresses in a ballastless slab track is found to have distinct differences from that in a ballasted track. The model testing results provide better understanding of the influence of dynamic soil–structure interaction and train speed on the response of track structure and soils. 相似文献