Ground Vibration Propagation Research Articles

Abrasive water jet cutting methods for reducing blast-induced ground vibration in tunnel excavation

This study assessed the controlling effect of abrasive water jet cutting on blast-induced ground vibration during tunnel excavation. The abrasive water jet cutting method adopted in this study includes the notch-cutting and disc-cutting methods. The abrasive water jet notch-cutting method was applied to block the propagation of blast-induced ground vibration in the transverse direction of the tunnel face, and the disc-cutting method was applied to suppress the blast-induced ground vibration in the longitudinal direction of the tunnel. The vibration-reduction effects of both methods were quantitatively investigated through experimental and numerical studies. In the experimental study, the vibration-reduction effect of notch cutting was compared with that of the line-drilling method, whereas the vibration-reduction effect of the disc cutting was measured against the case without disc cutting. In the numerical study, the effects of notch slot length and disc slot diameter were investigated. The abrasive water jet cutting method reduced the blast-induced ground vibration and was more effective than conventional drilling and blasting method in tunnel excavation.

Attenuation of ground vibrations using in-filled wave barriers

Ground vibrations generated by construction activities can adversely affect the structural health of adjacent buildings and foundations supporting them. Therefore propagation and rate of attenuation of construction induced ground vibrations is important during construction activities, particularly in urban areas where constructions are carried out in the vicinity of existing structures. In practice wave barriers are installed in the ground to mitigate the ground vibration propagation and hence to minimise the effect of ground vibrations on surrounding structures. Different types of fill materials such as bentonite, EPS geofoam and concrete are used in constructing wave barriers. In this study, a three-dimensional finite element model is developed to study the efficiency of different fill materials in attenuating ground vibrations. The model is first verified using data from full scale field experiments, where EPS geofoam has been used as a fill material in wave barriers. Then the same model has been used to evaluate the efficiency of open trenches, water filled wave barriers and EPS geofoam filled wave barriers on attenuation of ground vibrations. EPS geofoam is found to be the most efficient fill material, providing attenuation efficiency closer to open trenches. The efficiency of EPS geofoam and water filled wave barriers can be significantly increased by increasing the depth of the wave barrier.

Vibrations Caused By Train Passages In Underground Tunnel Compared To Vibrations From Ground Surface Transportation – Some Results Of Investigations

Abstract The paper describes experimental investigations of vibrations caused by train passages in the shallow underground tunnel (in Warsaw, Poland) in comparison to the results of measurements of vibrations from ground surface transportation (trams and buses). Propagation of surface ground vibrations from underground tunnel is presented. The problem of dynamic response of a building and influence of vibrations caused by underground on people residing in a building is discussed as well. The dynamic response of the building to underground vibrations is essentially different from the response of a building excited by surface sources of transport vibrations. Also the distribution of influence of the transport vibrations on people in the building is significantly different in both cases.

Influence of Variation in Track Support Rigidity Around Overbridges on Ground Vibration

Areas on each side of overbridges in embankment sections form border zones between the embankment and the girder, where ballast support rigidity varies, and track subsidence tends to occur. Investigations were thus conducted into the influence that ballast support rigidity variation and track subsidence can have on dynamic forces and the characteristics of ground vibration propagation, by means of a parameter study using dynamic analysis models. The effect was also evaluated of countermeasures for ground vibrations generated around the girder.

Line source response from geotechnical data

Predicting groundborne noise and vibration environmental impacts associated with rail transit projects involves determination of the line source response (LSR) to characterize ground vibration propagation characteristics. The presentation discusses the use of geotechnical data to develop model LSRs. GIS is then used to apply model LSR data on a larger scale and perform a detailed analysis using Federal Transit Administration (FTA) methodology, which can be refined with field testing at a later stage. Conceptual track vibration mitigation measures are discussed for controlling groundborne noise and vibration to nearby receptors.

Forensic engineering of construction vibrations

Construction equipment and operations generate ground vibrations that can affect adjacent and remote structures, and vibration effects range from disturbance of working conditions for sensitive devices and processes to reduction of structure serviceability and durability. Forensic engineering analysis of construction vibrations includes assessment of construction dynamic sources and their energy; soil contribution to wave propagation and soil deformations; evaluation of different structural responses to ground vibrations such as direct vibration effects on structures, resonant structural vibrations, resonant soil layer vibrations and dynamic settlement; condition surveys of structures that are imperative and contain complete information on structural responses and damage from vibration excitations; mitigation measures to prevent vibration effects; calculation of ground vibrations before construction; and appropriate assessment of measured vibrations. Detrimental soil vibrations and structural damage from construction sources can be prevented.

Evaluation of ground vibration induced by rail system

A series of field-measured data are used to characterize the ground vibration induced by the Taipei Mass Rapid Transit (TMRT) system on bridges. The measurements for analysis consist of various geological conditions with wide ranges of ground shear wave velocities. Both ground vibration beside bridge column and vibration propagation induced by TMRT are evaluated and then compared with those induced by the Taiwan High Speed Rail (THSR) system. Based on the analyses, the overall vibration level beside a bridge column is between 68 and 72 dB (ref. 1 micro-inch/sec). The overall vibration attenuation coefficients range from 2.1 × 10-3/m to 5.3 × 10-3/m, and the attenuation coefficient decreases with increasing ground shear wave velocity. The overall vibration influence distance increases with increasing ground shear wave velocity and is between 117 and 243 m. Meanwhile, the low and middle frequencies have the farthest influence distances for all soil types. Compared with the THSR, the vibration level and influence distance of the TMRT are lower. The attenuation coefficient of the TMRT on bridges is slightly higher than that of the THSR on both embankments and bridges. Further detailed discussions are also provided in the paper.

Investigating the influence of soil properties on railway traffic vibration using a numerical model

This paper presents the influence of dynamic and geometrical soil parameters on the propagation of ground vibrations induced by external loads. The proposed approach is based on a three-dimensional model, focusing on realistic excitation sources like impulse loads and moving railway vehicles. For the latter, a complete vehicle/track model is developed. The simulation is performed in time domain, offering an interesting approach, compared with classic cyclic analyses. The ground is modelled initially as an elastic homogeneous half-space and additionally as a layered half-space. First, the effect of homogeneous soil properties on ground vibration is analysed. Soil stratification is then taken into account, using various configurations. Analysis reveals that as receiver distance increases ground wave reflection in a layered ground plays an important role in the reduction of ground surface motion. This effect is magnified when the phase velocity wavelength becomes large compared with the depth of the surface layer.

Numerical modelling of ground borne vibrations from high speed rail lines on embankments

A three dimensional numerical model is presented capable of modelling the propagation and transmission of ground vibration in the vicinity of high speed railways. It is used to investigate the effect of embankment constituent material on ground borne vibration levels at various distances from the track.The model is a time domain explicit, dynamic finite element model capable of simulating non-linear excitation mechanisms. The entire model, including the wheel/rail interface is fully coupled. To account for the unbounded nature of the soil structure an absorbing boundary condition (infinite element) is placed at the truncated interfaces. To increase boundary absorption performance, the soil structure is modelled using an elongated spherical geometry.The complex geometries associated with the track components are modelled in detail thus allowing a highly realistic simulation of force transmission from vehicle to embankment. Lastly, quasi-static and dynamic excitation mechanisms of the vehicle locomotives are described using a multi-body approach which is fully coupled to the track using non-linear Hertzian contact theory.The resulting model is verified using experimental ground borne vibration data from high speed trains, gathered through field trials. It is then used to investigate the role of embankments in the transmission of vibration. It is found that soft embankments exhibit large deflections and act as a waveguide for railway vibrations which are trapped within the structure. This results in increased vibration levels both inside the embankment and in the surrounding soil. In contrast it is found that embankments formed from stiffer material reduce vibrations in the near and far fields.

Effects of soil profile and characteristic of exciting force on propagation of ground vibrations

Ground-borne vibrations caused by vibration sources such as road traffic and construction exhibit complicated properties during propagation from the vibration source to the inside of a building. In the present paper, a numerical analysis technique for the system of vibration source and propagation path of ground vibration is developed in order to systematically determine the propagation properties of the vibration as part of developing a predictive technique for exposure evaluations by vibrations in three directions at receiving points of vibration in the human body. First, the exciting forces in three directions for input into the numerical computation are inversely-estimated by using the measured acceleration records of the measurement points, which are near the vibration source. The thin-layered element method is used for numerical computation of the ground vibration. Then, the calculation results for the ground vibration obtained by using the estimated exciting force are compared with the measured results, and the influence of the stratified structure of the ground on the exciting force and the propagation properties of the ground vibration are studied. From these results, in a prediction of the ground vibration in three directions, it is emphasized that it is necessary to consider the influence of horizontal exciting force, although attention has been paid to only the vertical exciting force for simulating ground vibration.

Calibration and Deployment of a Fiber-Optic Sensing System for Monitoring Debris Flows

This work presents a novel fiber-optic sensing system, capable of monitoring debris flows or other natural hazards that produce ground vibrations. The proposed sensing system comprises a demodulator (BraggSCOPE, FS5500), which includes a broadband light source and a data logger, a four-port coupler and four Fiber Bragg Grating (FBG) accelerometers. Based on field tests, the performance of the proposed fiber-optic sensing system is compared with that of a conventional sensing system that includes a geophone or a microphone. Following confirmation of the reliability of the proposed sensing system, the fiber-optic sensing systems are deployed along the Ai-Yu-Zi and Chu-Shui Creeks in Nautou County of central Taiwan for monitoring debris flows. Sensitivity test of the deployed fiber-optic sensing system along the creek banks is also performed. Analysis results of the seismic data recorded by the systems reveal in detail the frequency characteristics of the artificially generated ground vibrations. Results of this study demonstrate that the proposed fiber-optic sensing system is highly promising for use in monitoring natural disasters that generate ground vibrations.

On the interest of integrating vehicle dynamics for the ground propagation of vibrations: the case of urban railway traffic

This paper presents a complete numerical model for studying the vertical dynamics of the vehicle/track interaction and its impact on the surrounding soil, with the emphasis on vehicle modelling. A decoupling between the track and the soil is proposed, due to the difficulty of considering all the subsystem components. The train/track model is based on a multibody model (for the vehicle) and a finite element model (for the track). The soil is modelled using an infinite/finite element approach. Simulations of both models are carried out in the time domain, which is better able to simulate the propagation of the vibration waves and to take into account the possible nonlinearity of a component. The methodology is applied in the case of an urban tram track and validated with the available experimental data. Models for the tram, the track and the soil are described. Results from the complete model of the vehicle and a simple model, based on an axle load, are compared with experimental results and the benefits of a complete model in the simulation of the ground vibration propagation induced by railway vehicles are demonstrated. Moreover, a parametric study of the vehicle wheel type is conducted, which shows the advantage of a resilient wheel, for various rail defects.

Prediction of a landslide and analysis of slide motion with reference to the 2004 Ohto slide in Nara, Japan

A slope 120 m wide and 100 m high collapsed including the roadbed of a national highway of Route 168 at Ohto, Nara, Japan on August 10, 2004. The precursory phenomena of abnormal features were found as cracks growing on the road-side slope 7 months before the catastrophe. The movements of the slope were monitored by extensometers. The data of the extensometers showed that creep mode turned from the secondary into the tertiary due to the heavy rainstorm of Typhoon Namtheun. The slide claimed no victims because the highway was closed 43 h before the catastrophe, anticipating a possible hazard when the creep velocity reached 4 mm/2 h. Comparison of rupture time predictions suggested that precision of the prediction using the reciprocal of creep velocity is higher than that by tertiary creep analysis, although leaving a problem that the prediction of the time zone of failure erred on the dangerous side. The slide generated ground vibration which was observed by seismometers deployed around the slide. Duration of the seismic signals corresponded well with the slide motion deciphered from video records. We found the fact that the seismic energy radiation from a landslide consisted of four stages. This had not been reported in any previous study, and may be important in understanding the dynamics of a rock-slide avalanche.

Calculation of ground vibration spectra from heavy military vehicles

The demand for reliable autonomous systems capable to detect and identify heavy military vehicles becomes an important issue for UN peacekeeping forces in the current delicate political climate. A promising method of detection and identification is the one using the information extracted from ground vibration spectra generated by heavy military vehicles, often termed as their seismic signatures. This paper presents the results of the theoretical investigation of ground vibration spectra generated by heavy military vehicles, such as tanks and armed personnel carriers. A simple quarter car model is considered to identify the resulting dynamic forces applied from a vehicle to the ground. Then the obtained analytical expressions for vehicle dynamic forces are used for calculations of generated ground vibrations, predominantly Rayleigh surface waves, using Green's function method. A comparison of the obtained theoretical results with the published experimental data shows that analytical techniques based on the simplified quarter car vehicle model are capable of producing ground vibration spectra of heavy military vehicles that reproduce basic properties of experimental spectra.

Modeling ground response functions in rock: A comparison of multiple methods.

Rail transit operations often produce groundborne vibration with energy that extends into the audible frequency range. It is often necessary to predict potential ground/structure-borne vibration and noise transmission in the design of new buildings in close proximity to existing rail lines or for new rail facilities/alignments. In a detailed analysis, key factors include source vibration characteristics (spectral force input to soil and/or track structure), ground vibration propagation characteristics (spreading and material damping losses), building foundation type (soil/structure interaction and coupling losses), and structural design of upper floors (floor and wall resonances and attenuation through the building). This paper focuses on methods for obtaining vibration propagation characteristics in rock which is an efficient transmitter of vibration at audible frequencies. Three methods for obtaining one-third octave band response functions are compared: empirical methods, finite element analysis, and seismic modeling.

Evaluation of ground vibration induced by high-speed trains on embankments

This study uses a comprehensive measurement scheme to evaluate the behavior of ground vibration propagation induced by high-speed trains on embankment structures. Both near-field and far-field vibrations are examined. A wide variety of geological conditions are studied. In the evaluation of the differences in vibration attenuation, various frequency dependences of attenuation coefficient�including overall vibration, low-mid-high range, and 1/3 octave bands�are applied to the field measurement data. In general, the near-field vibration level and overall vibration attenuation decrease with increasing ground shear wave velocity. Furthermore, the vibration attenuation at low frequency is smaller compared to the attenuation at high frequency. Based on these analyses, the interrelationships of vibration level, vibration attenuation, ground shear wave velocity, and frequency are established. Specific analysis recommendations are proposed for the application of ground vibration assessment in engineering and related fields.

Ground propagation of vibrations from railway vehicles using a finite/infinite-element model of the soil

The purpose of this study is to investigate the generation and propagation of ground vibrations induced by railway traffic, more specifically in the case of urban vehicles. The complete vehicle—track—soil model is developed according to an uncoupled approach: the vehicle—track subsystem is first simulated so as to provide the ground forces which, in turn, are applied to the model of the soil. The vehicle—track model is built with the help of the home-made C++library

The effect of discontinuity frequency on ground vibrations produced from bench blasting: A case study

A good number of empirical formulae and methods dealing with the analysis of the effects of blast-induced ground vibrations have been developed. The most common approach suggested for estimating the attenuation of particle velocity on the ground is to scale the distance (scaled distance, SD). This approach makes it possible to estimate the peak particle velocity when the amount of explosive charge or the distance or both are altered. Many parameters known to have an influence on particle velocity have been used for particle velocity prediction equations. Some of these parameters are maximum charge per delay, the distance between the station and shot location, burden, inelastic attenuation factor and site factors. However, the impacts of the discontinuities existing on the benches where blasts are detonated on the propagation velocity of seismic waves have not been taken into consideration in these equations. This study aims to examine the impacts of the discontinuity frequency parameter derived through geological measurements carried out on the blasting benches or nearby in a quarry mine (Supren, Eskisehir) in Turkey on the propagation of blast-induced ground vibrations. Developed based on the geological observations carried out on the benches, the model was formed by adding discontinuity frequency parameter to the particle velocity prediction model suggested by Nicholls et al. [Nicholls HR, Johnson CF, Duvall WI. Blasting vibrations and their effects on structures. Bulletin no. 656. Washington, DC: US Bureau of Mines; 1971]. In order to research the effect of the discontinuity frequency in the bench on the blast-induced ground vibrations, the relationship between the recorded peak particle velocity, scaled distance and discontinuity frequency was statistically evaluated for the site. The established relationship and the results of the study are presented.

Control of Traffic-Induced Ground Vibrations by Placing Heavy Masses on the Ground Surface

Although the main mechanisms of generating ground vibrations at source, e.g. by rail and road traffic, are now well understood, there are still very few investigations aimed to protect the affected buildings by influencing the propagation of ground vibrations, mainly Rayleigh surface waves, from a source to a receiver. A promising and cost effective method of screening the affected properties can be using heavy masses placed on the ground surface near the roads (e.g. concrete or stone blocks, specially designed brick walls, etc). The principle of operation of such masses is based on the fact that their natural frequencies of vibration, which depend on the mass value and on the local ground stiffness, can be chosen within the frequency range of railway- or road-generated ground vibrations (normally from 5 to 50 Hz). When the mass is shaken under the impact of incident Rayleigh surface waves, it scatters the incident waves into the depth of the ground and at different directions on the surface, thus resulting in noticeable resonant attenuation of transmitted ground vibrations. Using suitable combinations of such mass scatterers, one can expect to achieve efficient vibro-isolation of affected buildings. While some initial efforts have been made in the past to investigate the above-mentioned mass scatterers, largely by means of numerical calculations, very little progress in understanding their behaviour has been made so far. The aim of the present paper is to give a brief introduction to the theory of resonant mass scatterers and to discuss some problems that still need to be considered to achieve a fuller understanding of their operation as means of control of low frequency ground vibrations.

Ground vibrations produced by rock motions and debris flows

In this study we compare ground vibrations generated by various rocks and debris flows at the same channel to explore the origin of ground vibrations caused by debris flows. In field experiments we identified the ground vibrations caused by motions of individual rocks. Ground vibrations were detected by geophones and analyzed in the time‐frequency domains. We found that ground vibrations caused by individual rocks were 10–150 Hz and that larger stones generate ground vibrations with lower peak frequencies. A sphere‐packing model of granular rocks was used to estimate the propagation speed of ground vibrations. This was found to be underestimated when compared with our experimental data. The signal decay rate was obtained under the assumption that ground vibrations propagate as exponentially attenuating cylindrical waves. Ground vibrations produced by a debris flow at Ai‐Yu‐Zi Creek, Nan‐Tou, Taiwan, on 2 July 2004 revealed that the debris flow forefront produced vibrations lower than 50 Hz and ranged between 50 and 100 Hz after the front had passed. When the main front was closest to the sensor, the frequency spectrum covered a wide range, from 10 to 250 Hz. The mean velocity of the debris flow front was 13.3 m/s. Frequencies of ground vibrations caused by individual rocks are within the frequency range of ground vibrations captured during the debris flow, confirming that one of the main sources of ground vibration caused by debris flows is the interaction of rocks or boulders with the channel bed.