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- Ground vibration (12)
- Layered soil (6)
- Track-soil interaction (6)
- Railway track (5)
- Slab track (5)
- Train passage (5)
- Vehicle-track interaction (5)
- Force transfer (3)
- Hammer impact (3)
- Mitigation (3)
- Train-induced ground vibration (3)
- Wavenumber integrals (3)
- Axle sequence (2)
- Excitation forces (2)
- Field tests (2)
- Finite element method (2)
- Finite-element boundary-element method (2)
- Rail roughness (2)
- Railway (2)
- Rayleigh wave (2)
- Resonance (2)
- Static axle loads (2)
- Track vibration (2)
- Vehicle–track interaction (2)
- Wave propagation (2)
- Acoplamiento Método de los Elementos de Contorno-Método de los Elementos Finitos (1)
- Amplitude-distance law (1)
- Attenuation (1)
- Axle box measurements (1)
- Axle impulses (1)
- Axle-load spectra (1)
- Ballast mat (1)
- Ballast track (1)
- Base isolation (1)
- Beam dynamics (1)
- Beam-soil interaction (1)
- Bending waves (1)
- Blasting charge (1)
- Boundary Element Method-Finite Element Method coupling (1)
- Boundary element (1)
- Boundary element method (1)
- Bridge (1)
- Bridge resonance (1)
- Bridge vibration (1)
- Building response (1)
- Cancellation (1)
- Combined finite-element boundary-element method (1)
- Compliance function (1)
- Components of excitation (1)
- Continuous soil (1)
- Continuously inhomogeneous soils (1)
- Drop height (1)
- Dynamic axle loads (1)
- Dynamic loads (1)
- Dynamic pile and pile group stiffness (1)
- Dynamic soil-structure interaction (1)
- Elastic length (1)
- Elastic track elements (1)
- Emission (1)
- Environmental vibrations (1)
- Experimental verification (1)
- Explosion (1)
- Fequency domain (1)
- Filter effect of the soil (1)
- Filter effects (1)
- Finite element (1)
- Finite-element method (1)
- Flexible car body (1)
- Flexible plate (1)
- Flexible wheelset (1)
- Floating slab track (1)
- Foundations (1)
- Frequency-wavenumber method (1)
- Geometric trackbed irregularities (1)
- Geometric vehicle and track irregularities (1)
- High-speed trains (1)
- Insertion loss (1)
- Interacción dinámica suelo-estructura (1)
- Interaction (1)
- Interior load (1)
- Irregular soil (1)
- Irregularities (1)
- Irrégularités et forces roue-rail (1)
- Kinematic and inertial soil-pile-building (1)
- Layered soils (1)
- Mass drop (1)
- Material damping (1)
- Measured railway vibrations (1)
- Measurement campaigns (1)
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- Monitoring (1)
- Moving load (1)
- Multi-beam model (1)
- Multi-beam track model (1)
- Multi-beam-on-support model (1)
- Obstacles (1)
- Ondes du sol multicouche (1)
- Parametric excitation (1)
- Pile bending stiffness (1)
- Pile foundation (1)
- Plate-soil interaction (1)
- Prediction (1)
- Predictions (1)
- Quasi-static response; (1)
- Rail pad (1)
- Railway bridge (1)
- Railway forces (1)
- Railway induced vibration (1)
- Railway measurement campaign (1)
- Railway track vibration (1)
- Random dynamics and vibrations (1)
- Random stiffness variation (1)
- Randomly heterogeneous soil (1)
- Reduction (1)
- Resonancia en edificaciones (1)
- Resonant response (1)
- Rigid vehicle model (1)
- Scattered axle impulses (1)
- Scattering (1)
- Scattering damping (1)
- Sleeper pad (1)
- Soil forces (1)
- Soil stiffness (1)
- Soil transfer function (1)
- Soil-building interaction (1)
- Stiffness (1)
- Stiffness variation (1)
- Target stiffness (1)
- Track (1)
- Track alignment (1)
- Track and vehicle irregularities (1)
- Track damage (1)
- Track damage monitoring (1)
- Track damage quantification (1)
- Track deflection (1)
- Track deformation (1)
- Track displacements (1)
- Track dynamic (1)
- Track filter (1)
- Track filtering (1)
- Track-soil and vehicle-track resonances (1)
- Train induced ground vibration (1)
- Train speed (1)
- Train-induced vibration (1)
- Trench (1)
- Tunnel (1)
- Tunnel-to-surface reduction (1)
- Under-sleeper pads (1)
- Varying track stiffness (1)
- Vehicle-track-soil interaction (1)
- Vibration (1)
- Vibration isolation (1)
- Vibration reduction (1)
- Wave attenuation (1)
- Wave excitation (1)
- Wavenumber domain (1)
- Wavenumber method (1)
- Wheel out-of-roundness (1)
- Wheel-rail irregularities and forces (1)
- Wheelset (1)
- Wheelset accelerations (1)
- Wind energy tower (1)
- layered soil (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (16)
- 7.2 Ingenieurbau (16)
The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation ν ~ r -q where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(-kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.
Construction work, such as pile driving and soil compaction, or road and railway traffic excite nearby buildings, and the perceptible or audible vibration can be a nuisance for nearby inhabitants. A simplified building model has been created for these situations, which includes the effects of soil-structure interaction, the low-frequency amplification along the height of the building as well as the high-frequency reduction and the floor resonances. The model consists of one wall for all supporting structures (walls and columns) and one floor for each storey. The effect of different floor resonance frequencies is included in a stochastic procedure. The soil is modelled by a spring and a viscous damper, and the free-field amplitudes of the soil are applied under this soil element.
The model can be calculated by transfer matrices or in a continuous wave-type version where an analytical solution can be evaluated numerically. The building response in the high-frequency (acoustic) region is calculated as mean values over wider frequency bands. The approach to an infinite building model can be found for these high frequencies and the corresponding soil-structure transfer can be described by the ratio of impedances at foundation level.
The rules for choosing the parameters to obtain realistic results are derived from complex calculations for example, for the stiffness and damping of building foundations and many measurements as for the damping of floor resonances. The influences on the floor resonance from the soil (damping) and the supporting structure (detuning) are important. Some more effects will be discussed by the simplified and detailed models and by measurements to establish a good understanding of ground-induced building vibrations.
The train passages over intact or damaged slab tracks on different soils have been calculated by the finite-element boundary-element or the wavenumber-domain method. The influence of track and soil parameters on the distribution of the track displacements and the soil forces has been analysed. The measured and calculated displacement time histories of train passages could be used to identify track damages such as lose sleepers or a lose track plate. The time histories and spectra of the soil forces can explain the measured ground vibration reduction of slab tracks. The calculated displacement and force distributions of slab tracks on continuous soils do not fulfil the Winkler hypothesis and Winkler models should not be used for track analysis.
Ground vibrations due to different technical sources are analysed in theory and experiment for the dispersion of Rayleigh waves and the admittance spectra. Both tasks are theoretically based on the same concept: The admittance function in frequencywavenumber domain yields the dispersion as its maxima, and the admittance function in space domain is obtained by integrating it over the wavenumbers. On the experimental side, many signal processing methods have been applied to many sites and have been developed by the authors in the last 35 years, i.e., time-domain methods, including the cross-correlation method, and frequency-domain methods such as the spectral analysis of surface waves with two or multiple sensors, the wavenumber-transform method, and the spatial autocorrelation method. All methods are presented by their basic formula and by at least one example site. Different sensor arrays and deterministic and stochastic sources have been tested for the spatial autocorrelation method and the wavenumber-transform method at several sites. In addition, all frequency-domain methods are presented for a specific layered site comparing their quality. The evaluated dispersion curves are very similar, but a somewhat higher frequency range has been found for the fastest method, i.e., the multi-sensor spectral-analysis-of-surface-waves method. The theoretical solutions have been used for the inversion of the measured dispersion to the soil profile of the specific layered soil. The theoretical soil model has subsequently been used to predict the ground vibration spectra of hammer and railway excitation that exhibit a good agreement with the corresponding measurements. Thus, the contribution shows the benefit of active and passive seismic methods for the prediction of railway vibration, including a new version of the spatial autocorrelation method for technical vibrations. On the other hand, technical and namely railway vibrations are considered a seismic source for the exploration of near surface soils.
A combined finite-element boundary-element method for the dynamic interaction of the soil with flexible structures such as single piles or complete wind energy towers has been developed. Flexible piles in different soils are analysed in frequency domain. The different parameters such as the stiffness of the soil, the bending stiffness and the radius of the hollow pile are analysed for their influence on the complex compliances. The results have been determined as specific power laws which are different for the different load cases (horizontal, rocking, coupling) and for the different soil models (Winkler, continuum with constant, root-parabolic and proportional-linear stiffness variation). The strongest influence of the soil stiffness can be found for the homogeneous soil and the horizontal component. Winkler soils have a weaker influence than the corresponding continuous soils. An offshore wind energy tower has been modeled and calculated for wind and wave loads.
Irregularities of the track are a main cause of train-induced ground vibration, and track maintenance is of great importance. Although geometric irregularities at the wheel-rail contact are widely used, other types of irregularities, such as stiffness irregularities, irregularities from different track positions and irregularities in the wave propagation, were analysed in the present study. The track behaviour was investigated by a multi-beam-on-soil model. This track model is coupled with a vehicle model to calculate the vehicle–track interaction. The track model was also used for the track filtering, which transfers a track support error to the equivalent rail irregularity or, conversely, the sharp axle pulse on the rail to a smoother pulse on the soil. In the case in which this filtering varies randomly along the track, the pulses of the moving static load induce a certain ground Vibration component (“the scatter of axle pulses”). This effect was calculated by the superposition of axle pulses in the frequency domain and by a stochastic simulation. Simultaneous vehicle, track and soil measurements at a certain site were used to evaluate the different excitation and ground Vibration components. The agreement between calculations and axle-box and soil measurements is good. The ground vibrations calculated from rail irregularities and corresponding dynamic loads, however, clearly underestimate the measured ground vibration amplitudes. Only the static load that is moving over a varying track support stiffness can produce the important mid-frequency ground Vibration component by the scatter of axle pulses.
Ballast mats are an efficient measure to reduce the vibrations near railway lines. The vehicle-track system gets a low eigenfrequency due to the insertion of an elastic ballast mat under the ballast. For frequencies higher than this low vehicle-track eigenfrequency, the forces, which are generating the vibration of the soil, are considerably reduced. In this contribution, a combined finite-element boundary-matrix method is used to calculate a number of completely three-dimensional track models with and without ballast mats. The influence of the important parameters such as the stiffness of the ballast mat, the unsprung vehicle mass, the mass of the track, and the stiffness of the subsoil is investigated. The numerical results are presented as the transfer functions of the total force that is acting on the soil and generating the vibration of the environment. The effectiveness of ballast mats is achieved by division of two of these force functions. The general tendencies for this insertion loss are discussed and a comparison with measurements is given. To come to an improved practical tool for the design of ballast-mat tracks, the finite-element method results are approximated by a simple two-dimensional model of which the solution is given explicitly.