Soil Vibration Research Articles

Method for identifying the leakage of buried natural gas pipeline by soil vibration signals

Method for identifying the leakage of buried natural gas pipeline by soil vibration signals

Method for Predicting Environmental Vibration Impact of Existing Subway Lines and Its Practical Application

To predict accurately the impact of track vibrations caused by subway trains on adjacent buildings and address the problem of their excessive dynamic response, a method for predicting the environmental vibration impact of existing subway lines is proposed in this paper. A coupled numerical dynamical model of the train/track/tunnel system is established using the multi-scale method. Using field-measured soil vibration data, empirical formulas for soil frequency and material damping coefficient are calibrated. By combining the numerical model and the empirical formulas, buildings’ indoor vibrations and noise level can be assessed. At the same time, a solution to the problem of excessive vibration of buildings along a subway line is also proposed that optimizes the track fastener parameters. Field tests verified the accuracy of the prediction method and the effectiveness of the optimized track parameters. These research results provide a reference for predicting the vibration of buildings along subway lines and using the proposed preventive solutions.

High-strain dynamic model of large-diameter pipe piles with soil plug for vertical vibration analysis

A rigorous analytical model is developed for simulating the vibration behaviors of large-diameter open-ended pipe piles (OEPPs) and surrounding soil undergoing high-strain impact loading. To describe the soil behavior, the soil along pile shaft is divided into slip and nonslip zones and the base soil is modeled as a fictitious-soil pile (FSP) to account for the wave propagation in the soil. True soil properties are adopted and slippage at the pile-soil interface is considered, allowing realistic representation of large-diameter OEPP mechanics. The developed model is validated by comparing with conventional models and finite element method (FEM). It is further used to successfully simulate and interpret the behaviors of a steel OEPP during the offshore field test. It is found that the variation in the vertical vibrations of shaft soil along radial direction is significant for large-diameter OEPPs, and the velocity amplitudes of the internal and external soil attenuate following different patterns. The shaft soil motion may not attenuate with depth due to the soil slippage, while the wave attenuation at base soil indicates an influence depth, with a faster attenuation rate than that in the pile. The findings from the current study should aid in simulating the vibration behaviors of large-diameter OEPP-soil system under high-strain dynamic loading.

Analysis of Soil Differences in Subway Vibration Transmission Paths

Current challenges in collecting and analyzing subway vibration data include the absence of standardized data collection methods, limitations in data analysis techniques, and an unclear understanding of the effects of geological conditions on vibrations. This study investigated vertical vibrations of tunnel walls and the ground above tunnels under different geological conditions of soft soil and rock strata at horizontal distances of 0, 15 m, and 30 m from the tunnel center line during train passages. The collected data underwent Fourier transformation and 1/3 octave processing to extract spectral characteristics and analyze transmission losses across different frequency bands. Our findings revealed two vibration peaks in the transmission process for both soft soil and rock formation geology. Specifically, high-frequency vibrations in soft soil experienced greater attenuation when transmitted from the tunnel wall to the ground at 0 m, while low-frequency vibrations in rock formations showed greater attenuation. We also observed a vibration amplification phenomenon at 15 m under soft soil geology conditions. Although low-frequency vibrations below 12.5 Hz showed slight attenuation within a 30 m test distance under both geological conditions, vibrations above 40 Hz experienced significant attenuation. These results offer valuable insights for reducing vibrations in subway superstructures and planning subway lines under diverse geological conditions. Furthermore, this study serves not only as a basis for mitigating vibrations in metro spans and designing metro lines in various geological contexts but also establishes a scientific foundation for future research.

Investigation of Vibration Characteristics during Various Building Construction Stages under Train Operations

In response to land use challenges, major urban centers have started implementing over-track building constructions above metro lines as a means of accommodating residents and workers. However, the continuous operation of trains can generate excessive vibrations that may negatively impact the overall living conditions for occupants residing in these structures. In this paper, vibration measurements were conducted on the soil and within a three-story frame structure building. Additionally, a three-dimensional finite element model of the track–soil–building was established. The wheel–rail contact force was incorporated as a dynamic load that varies with time to accurately simulate the vibration response induced by trains. According to the construction process of the over-track building, four construction stages were set up using the finite element model to study the impact of the construction stages on the vibration propagation from the soil to building structure. The results indicate that the presence of existing structures exerts a mitigating influence on soil vibrations. Pile foundation construction can effectively mitigate soil vibration to a significant extent. The findings provide references for the future development and design of over-track buildings.

Analysis of Vibration Responses Induced by Metro Operations Using a Probabilistic Method

The environmental vibrations of tunnels and soil caused by metro operations is one of the most important issues in the field of environmental geotechnical engineering. Recent studies in metro-induced vibrations have revealed significant uncertainties in the vibration responses of tunnels and the surrounding soil. A two-step method of obtaining train loads considering uncertainty was introduced. The first step was to obtain the train loads via an inverse model based on measurements, and the second step was to quantify the uncertainty of train loads based on complex principal component analysis. A portion of a tunnel of the Beijing metro was selected as the object of study, where the vertical accelerations on the rail and on the tunnel wall were measured under different train speeds of 35, 45 and 55 km/h. Inputting the train loads based on the measured rail accelerations into an axisymmetric numerical model, established using ANSYS, the vibration responses of the tunnel wall in a probabilistic framework were calculated and were compared with the measured results. By using an accuracy index that considers both calculation bias and uncertainty, the accuracy of the calculated vibration response was quantitatively evaluated. It can be concluded that the calculated vibration response can reflect the actual vibration level and uncertainty of the tunnel wall. The accuracies of the calculated results under different speeds were generally high while showing a slight difference in amplitude.

Railway induced ground vibrations in soft soil

Railway induced ground vibrations in soft soil

Investigation on the Damping Effect of FST System under Moving Load Using the Track–Tunnel-Layered Saturated Ground Model

In this paper, a single-tier beam-spring-damping system and a two-tier beam-spring-damping system are adopted to simulate the FT (fixed track) and FST (floating slab track) system, respectively. The tunnel is modeled as an infinitely long Euler—Bernoulli beam embedded in the layered saturated soil. By solving the governing equations of the saturated soil and employing the TRM (transmission and reflection matrices) method, the frequency response function of the tunnel-layered saturated soil model is obtained. Making use of the interaction between the tunnel and track systems, the track system is coupled with the tunnel-layered saturated ground model. The solutions for the dynamic response of the track system–tunnel-layered saturated ground model under moving loads in the time–space domain are obtained using the inverse Fourier integral transform. To evaluate the damping effect of the FST system on the vibration of tunnel and soil, four damping coefficients are defined and the vibration results of the FT system–tunnel-layered saturated soil model are compared with those of the FST system–tunnel-layered saturated soil under different moving loads and soil conditions. The numerical results show that both the vibration displacement and acceleration amplitude are attenuated after using the FST system, and the damping coefficient of acceleration is about 30% greater than that of the displacement. In addition, the damping effect of the FST system on the ground surface vibration is associated with the embedded depth of the tunnel and the soil stiffness.

Lateral dynamic responses of coastal group piles considering pile‒water‒soil interactions

In this paper, an analytical framework is developed to investigate the dynamic impedance of pile groups comprising an arbitrary number of cylindrical piles connected with a rigid cap. The solution considers the combination of the secondary ground wave effects transferred by the pile‒soil vibration and the hydrodynamic pressure from the pile‒water interaction. A displacement attenuation function is introduced to define the pile‒to‒pile interaction factor, which describes the relationship between the active and passive piles based on the soil reaction development. The pile is modeled as a Euler‒Bernoulli (EB) beam, and the hydrodynamic pressure is calculated using radiation wave theory. Biot's dynamic poroelastic theory describes the saturated soil around the piles. The rationality and correctness of the proposed theoretical model are verified by degenerating the solution to the existing research results. An extensive parametric analysis is conducted to investigate the effect of various factors on the lateral dynamic impedance of the group pile. Moreover, some interesting findings and meaningful conclusions are obtained.

Sustainable use of End-of-Life-Tires (ELTs) in a vibration isolation system

Huge stockpiles of End-of-Life Tires (ELTs) are of major global concern. This paper investigates and helps to demonstrate the beneficial utilization of ELTs to provide geotechnical seismic isolation (GSI) of machine foundations located on a rubber-soil mixture (RSM). A series of laboratory tests is conducted to extend the understanding of RSM behavior beyond that previously elaborated, particularly by demonstrating the efficiency of the GSI-RSM system and by defining its optimal parametric values. The results indicate that increasing the thickness of the RSM layer and soil cap, along with the addition of rubber content, up to the optimum values lead to enhanced performance. Beyond these optimum values, the benefits start to decrease. For the determined optimum rubber content (8%), RSM layer thickness (0.1B), and soil cap thickness (0.15B) at a vibration moment level of 0.17 N.m, the GSI-RSM system achieves maximum reductions of 36%, 43%, and 77% in resonant frequency, resonant displacement, and resonant acceleration, respectively, compared to untreated beds. Moreover, the GSI-RSM system effectively reduces the developed peak particle velocity (PPV) and kinetic energy, independent of the excitation frequency. The increased damping and significant energy dissipation demonstrates the system’s effectiveness in mitigating vibrations. This environmentally-friendly technique presents a low-cost alternative for improving the vibration behavior of soil beds. It provides the basis for the wider adoption of ELTs for GSI, for machine foundations and for other infrastructure projects with similar soil vibration concerns, including building foundations, transportation infrastructure and industrial facilities. In this way the research contributes to the growing body of sustainable practices in the construction industry.

Experimental assessment of train-induced soil vibration characteristics using Arduino-based accelerometers

Experimental assessment of train-induced soil vibration characteristics using Arduino-based accelerometers

Numerical modelling and analysis for nonlinear stiffness of subgrade soil subject to 3-D vehicle-track interaction

In this paper, a subgrade model with nonlinear stiffness is established and integrated into a previously constructed 3-D vehicle-track-subgrade (VTS) dynamic model, in which the prediction and assessment of the vehicle-induced railroad vibrations are achieved with high accuracy and versatility. The system excitations are originated from the initial and time-dependent geometric irregularity of the system, which includes several internal excitations, namely conventional rail irregularity and the soil deformation-induced track irregularity. In the numerical analysis, the nonlinear behavior of the subgrade soil is revealed by considering shear modulus and traffic loads. The numerical experiment indicates that subgrade soil has a greater dynamic stiffness reduction if the vehicle enters the soil region with initial deformations. Besides, it is shown that the soil vibrations will be significantly amplified once the vehicle running speed is larger than the Rayleigh wave velocity of the subgrade soil.

Numerical investigation of soil dynamic response during high-frequency vibratory pile driving in saturated soil

The high-frequency vibratory pile driving has been gradually applied for pile installation in central urban areas. However, its adverse impact on the surrounding environment is still uncertain. This paper develops a refined three-dimensional numerical model based on the hydro-mechanical coupling method to investigate soil dynamic responses produced by high-frequency vibratory pile driving in saturated soil. The soil vibration velocity, pore water pressure, and mean effective stress are analyzed. Additionally, parametric analyses of excitation frequency and excitation force are conducted to examine soil responses under different installation parameters. The results show that the peak particle velocity (PPV) of soil reaches its maximum at the depth of the pile tip, with greater vertical PPV below the ground surface than radial PPV. Pore water pressure around the pile increases significantly, leading to a noticeable reduction in effective stress. The changes in pore water pressure and effective stress decrease as the distance from the pile increases. The parametric analysis results indicate that increasing the excitation frequency can significantly decrease the vertical PPV of soil at the depth of the pile tip and reduce the stress disturbance range in the surrounding soil. The pressing force mainly affects the efficiency of pile sinking, while the centrifugal force primarily affects the stress state evolution of soil around the pile shaft.

DESCRIPTIVE STATISTICAL CALIBRATION METHOD OF TRIAXIAL DIGITAL ACCELEROMETER ADXL345 AS EARTHQUAKES SENSOR

Seismic monitoring networks are the crucial elements in strong motion seismology for effective risk reduction. Low scale lateral variation of high intensity ground movement caused by earthquakes will be detected more effectively with densely located networks. However, the limitations of developing such project are rooted in expensive costs associated with the construction and installation in addition to bulky size of the conventional seismic observation system. Recently, micro-electromechanical system (MEMS) has being recognized in the applications of seismological and earthquake engineering due to the high precision obtained in these micron size semiconductor instruments and cheaper alternative for traditional seismic detector. ADXL345 is a type of digital triaxial MEMS accelerometer that is ideal for measurement of low-frequency vibrations and static accelerations of gravity, which makes it suitable for ground motion detection. Thus, this study aims at calibrating ADXL345 sensor that is required as sensing component in an affordable earthquake monitoring system with the Earthquake Benchmarking System (Penanda Aras Gempa Bumi, PAG) available in the inventory of Department of Mineral and Geoscience Malaysia, Sabah. Soil vibrations in EW (east-west or x-axis), NS (north-south or y-axis), and UD (up-down or z-axis) directions during random forces hit on the surface are recorded by both accelerometers. Acceleration magnitudes recorded by PAG and ADXL345 are extracted and data exploration is performed. Predominantly, ADXL345 measurements in horizontal and vertical ground movements are on a higher scale than the reference device. Subsequently, evaluation by using descriptive statistical analysis is chosen to produce numerical equations for data correction operations. İmplementation of the mathematical functions in ADXL345 for observing land movements in EW, NS, and UD directions resulted in decreasing the range values of output readings. Higher approximation of magnitudes of ground motion with the PAG system is achieved.

Application of cross-spectral analysis and fast Fourier transform to detect soil vibrations in the natural and technical geosystem of the Dniester PSPP

The main purpose of the study is to identify the relationship between changes in water level and soil deformation, where the cyclic change in loads on the reservoir bed is the stress deviator, i.e., the PSPP reservoir acts as an oscillator of transverse vibrations, and the soil extensometer performs the function of reading and recording these vibrations. Methodology. Solution of the problem requires recording the time series of water level fluctuations and extensometer sensor fluctuations on all depth horizons. It is also necessary to perform a fast Fourier transform for water level fluctuations separately and similarly to each extensometer sensor fluctuation. We need to separately calculate the signal power spectrum of all sensors in the soil, and compare the amplitude-frequency, phase-frequency components of the power spectra of water level oscillations and vertical oscillations of the extensometer sensors. Results. During the studies, it was found that the PSPP reservoir is a source of low-frequency vibrations in a wide spectral range. These vibrations have a very long wavelength, measured in tens of thousands of kilometers, which can propagate over long distances, both along the front of geological layers and in depth. Scientific innovation. The research in this article allows us to more accurately assess the frequency spectrum of vibrations and identify possible resonance phenomena that may occur in soils during the operation of a power facility. In addition, this study was conducted in a specific region, which makes it possible to obtain more accurate data on the impact of low-frequency vibrations on the geosystem in this region. Thus, this paper may be of interest to specialists in the field of geotechnics, geology, and energy. It can also be used in the planning and operation of other power facilities in similar conditions. Practical significance. Low-frequency waves can be detected by seismic instruments such as seismometers. The results of this study will help to correct the analysis and interpretation of seismograms, which is important for understanding the processes occurring in the hydroelectric power plant operation area.

Enhanced mixed boundary for modeling infinite domain in 2.5D soil vibration analysis

In this paper, an enhanced mixed 2.5D boundary for treating the infinite domains of the half-space is proposed. Unlike the perfectly matched layer (PML) that has a fixed outer boundary, the proposed method replaces the fixed outer boundary by infinite elements (IFE) to allow waves to propagate uninterruptedly to infinity. Such an approach not only improves the absorption capacity of the PML, but reduces its dependence on the attenuation function. The proposed boundary in the stretched coordinates is formulated in detail, for which the criteria for selecting the reference wavenumbers for multi types of waves are deliberately analyzed. A comprehensive parametric study for assessing the accuracy of the proposed boundary is presented, where the superiority of the proposed boundary relative to the pure PML and IFE is demonstrated. Particularly, the optimal ranges of parameters of the proposed boundary are identified. For illustration, the proposed boundary is applied to analyzing the frequency and time domain responses of a surface train moving at sub- and super-critical speeds. The results indicate that the proposed method can accurately predict the wave propagation characteristics, including the Mach cone at super-critical speeds.

Design and Development of Multi-Sensor ADEP for Bore Wells Integrated with IoT Enabled Monitoring Framework

Typically, about 51% of the groundwater satisfies the drinking water worldwide and is regarded as the major source for the purpose of irrigation. Moreover, the monitoring and assessment of groundwater over bore wells is essential to identify the effect of seasonal changes, precipitations, and the extraction of water. Hence, there is a need to design a depth sensor probe for bore wells so as to analyze/monitor the quality of underground water thereby estimating any geophysical variations like landslides/earthquakes. Once the depth sensor probe is designed, the data is collected over wireless sensor network (WSN) medium and is stored in cloud for further monitoring and analyzing purposes. WSN is the major promising technologies that offer the real-time monitoring opportunities for geographical areas. The wireless medium in turn senses and gathers data like rainfall, movement, vibration, moisture, hydrological and geological aspects of soil that helps in better understanding of landslide or earthquake disasters. In this paper, the design and development of geophysical sensor probe for the deep bore well so as to monitor and collect the data like geological and hydrological conditions. The data collected is then transmitted by wireless network to analyze the geological changes which can cause natural disaster and water quality assessment.

Experimental and numerical investigation on seismic response of the soil-structure cluster interaction system

With the rapid advancement of urbanization in recent decades, a large number of surface dense buildings have appeared. Soil-structure cluster interaction (SSCI) has attracted widespread attention. However, most current research is based on numerical simulations, and studies using shaking table tests are rare. Here, a series of shaking table tests of soil-structure interaction and SSCI systems were designed and conducted to investigate the effect of SSCI on the response of the structure and site soil. The number of structures, seismic wave types, and amplitudes were considered. The numerical method was verified based on test data. The test data and numerical results indicate that (1) the presence of surface buildings does not always reduce the free-field soil motion. However, the soil vibration decreases as the number of surface structures increases. (2) The maximum influence of SSCI effects on the roof acceleration and displacement of the central building (CB) can be as high as –23% and −18%, respectively. (3) The relative deformation of the structure decreases with an increase in the number of structures, and the relative deformation of the middle layer is the largest. (4) Different evaluation indices can yield roughly the same results, although the focus of each evaluation index is different. (5) A denser layout enhances the SSCI effect and further reduces the response of the CB when the urban density of the structural cluster is the same.

Cooperative verification of urban noise sources from generated acoustic and seismic waves

In this work, co-operative verification of acoustic and seismic wave generating noise sources within an urban environment is presented. Sound and soil vibration produced from everyday urban noise sources including trains and vehicles are measured. Acoustic and seismic sensors can detect vehicles passively, independent of weather and daylight, at long ranges. Both signals contain contributions from the engine. Simulated and measured results will be presented and discussed

Soil vibration and auralisation software tools for application in railways

The main objective of the SILVARSTAR Shift2Rail project is to develop validated software tools in the field of ground vibration and auralisation. The first project work stream focuses on the prediction of ground vibration through the development of a hybrid approach, combining numerical prediction with experimental results. The general framework adopted expresses the vibration level in a building as the product of terms describing the source, the propagation through the soil and the receiver. In the second work stream, auralisation and Virtual Reality (VR) software tools are developed based on physical models to synthesise railway noise in high quality. The novel auralisation and VR tools enable perception-based evaluation of noise mitigation technologies and an effective demonstration of different noise scenarios, including noise mitigation measures and vehicle design variants.