Attenuation Relationships Research Articles

Development of Synthetic Ground Motion-based Attenuation Relationship for Bihar Region for Seismic Ground Response Analysis Considering Central Seismic Gap

Ground Motion Prediction Equation (GMPE) is one of the significantly important tools to perform the seismic hazards analysis of any region. Therefore, the development of GMPEs at the bedrock level is utmost important especially when the region does not have any earthquake recording stations. The present study discussed the development of a GMPE at bedrock level for the Bihar region based on the stochastic model. The different seismic parameters such as magnitudes (Mw) 4.0‐8.5, spectral periods of 0‐10 s and distances up to 300 km have been considered for the stochastic model. Based on the results, it was found that the stochastic model is capable to predict the ground motion synthetically and the proposed GMPE, for Bihar region, predicts the spectral acceleration in most precise way. Further, the ground motion amplification analysis was carried out using synthetically generated bedrock motion to analyze the effect of soil deposits on the amplification or de‐amplification of the bedrock peak ground acceleration. It was found that that the seismic wave gets amplified at ground level by 10% to 70% from the input motion PGA ranging from 0.175g‐0.435g, indicating amplification and de‐amplification of seismic wave. The maximum spectral acceleration at surface level was also found to be increased by approximately 60%, 56% and 27%, when bedrock input motion of PGA = 0.175g, 0.256g and 0.435g, respectively. Thus, based on the results, it can be stated that the developed GMPE can be used to assess the seismic hazards analysis in Bihar region. Further, it can be suggested that there is a need of the development of a predictive attenuation relationship at the surface level PGA, for Bihar region or any earthquake prone area, incorporating different site classes and regional seismicity since, the seismic wave amplified due to the presence of soil deposits.

Analysis of Peak Ground Acceleration Attenuation Characteristics in the Pazarcik Earthquake, Türkiye

This study collected acceleration records and station reports from 379 strong-motion stations triggered by the Mw7.7 earthquake in Pazarcik, Türkiye, on 6 February 2023. A total of 451 horizontal and 194 vertical strong-motion acceleration records with complete waveforms and reasonable data were selected to establish appropriate equations for predicting seismic parameters. Two iterative algorithms, specifically the optimization algorithm and orthogonal distance regression, were employed to formulate prediction equations for PGA and EPA in the NS (north–south), EW (east–west), and vertical directions. Furthermore, a comparative analysis of the attenuation curves for PGA and EPA was conducted within the vertical and horizontal directions. The results indicated that the observed and predicted values of vertical PGA and EPA at the same fault distance were approximately 0.577–0.673 times those of horizontal PGA and EPA. The ratio range calculated in our study aligns closely with previous research results, slightly more than 2/3 only in the vicinity of fault zones. The analysis demonstrated that the horizontal PGA value of the soil site at the same fault distance was approximately 1.46 times that of the bedrock site, while the vertical PGA value was only 1.12 times. The comparison of attenuation relationships revealed that within the fault distance range of 20 km to 100 km, the horizontal PGA of the Wenchuan earthquake was approximately 1.26–2.16 times that of the Pazarcik earthquake, and the ratio increased with an increasing fault distance.

Determining Attenuation Q-Factor Values for Selected Seismic Stations in Iraq

The coda wave decay (CWD) method was used to estimate the quality factor from the coda wave amplitude decay rate for the broadband seismic stations (IBDR, MSL, and NSR4) using a single backscattering model. This research aims to calculate the attenuation coefficient and the frequency-dependent coefficient (α) for three stations and compare them to comprehend the details of Earth's crust structure in those stations. Then, to test if they are homogenous or not. Also, investigate how sensitive extracted values to tectonic differences in study stations. The attenuation properties are important for providing information about the medium that seismic waves pass through and can also be applied to areas with seismic activity as initial disaster mitigation. The study used data from the Mesopotamian Network (MP) and the Iraqi Meteorological Organization and Seismology (IMOS) from 2011 to 2021. The selected earthquakes have less than < 100 km epicentral distances, and magnitudes ranging from 3.5 to 5.6. Forty-six earthquakes were recorded by three stations (IBDR, MSL, and NSR4). These earthquakes were analyzed at eight center frequencies (1, 2, 3.5, 6, 8, 10, 12, and 16 Hz) and a 30-sec length window by using the SEISAN Earthquake Analysis Software. The QC values are computed by the frequency-dependent relationship QC= Q0 f α, where Q0 is QC at 1Hz and α denotes frequency dependence degree. The attenuation relationship of the station IBDR is obtained as QC =98 f 1.07, QC = 99 f 1.09 in the MSL station, and QC = 77 f 0.98 in the NSR4 station. The results showed that low Q0 corresponds to high attenuation. The comparison of the estimated QC for these three stations indicates that attenuation is highest at NSR4, followed by other stations.

Ground motion emissions due to wind turbines: observations, acoustic coupling, and attenuation relationships

Abstract. Emissions from wind turbines (WT) cover a wide range of infrasound and ground motions. When they are perceived as immissions by local residents, they can become a source of disturbance or annoyance. To mitigate such disturbances, it is necessary to better understand and, if possible, suppress WT-induced emissions. Within the project Inter-Wind we record and analyze ground motion signals in the vicinity of two wind farms on the Swabian Alb in southern Germany, simultaneously with acoustic and meteorological measurements, as well as psychological surveys done by cooperating research groups. The investigated wind farms consist of 3 and 16 WTs, respectively, and are located on the Alb peneplain at 700–800 m height, approximately 300 m higher than the two municipalities considered in our study. Our main aim is to better understand reasons why residents may be affected from WT immissions. Known ground motions include vibrations due to eigenmodes of the WT tower and blades, and the interaction between the passing blade and the tower, causing signals at constant frequencies below 12 Hz. In addition, we observe signals in ground motion recordings at frequencies up to 90 Hz which are proportional to the blade-passing frequency. We can correlate these signals with acoustic recordings and estimate sound pressure to ground motion coupling transfer coefficients of 3–16.5 µms-1Pa-1. Sources for these emissions are the WT generator and possibly the gearing box. The identification of such noise sources can help to find measures to reduce disturbances in order to increase the public acceptance of WTs. Residents perceive more disturbance at the location where the wind farm is closer to the municipality (approximately 1 km). However, there is also a major railway line which produces higher vibration and infrasound signal amplitudes compared to the WTs. Along the measurement lines the decay rate of the WT-induced ground motions is determined for a damping relation proportional to 1/rb. We find frequency-dependent b values for different scenarios at our geological setting of Jurassic limestone on marl, sandstone, and Quaternary deposits. These damping relationships can be used to estimate emissions in the far field and to plan mitigation strategies.

Analysis of the Aggregation Characteristics and Influencing Elements of Urban Catering Points in Small Scale: Methods and Results

Urban catering systems constitute an important subsystem of the complex urban system. They can reveal not only the impact of urban functional structure on the catering but also the behavioral patterns of individual catering points through the exploration of their small-scale aggregation characteristics and influencing elements, thus becoming an essential basis for urban functional planning. In this study, we analyze the aggregation characteristics of catering points in a particular study area using the probabilistic methods, with Beijing catering points as a sample. The analysis revealed a good power-law distribution characteristic of the catering points density at the small scale. Then, an aggregation effect analysis model and an agglomeration effect analysis model were established. Based on this, an empirical analysis of candidate agglomeration kernel elements was conducted. The results showed that the influence of candidate agglomeration kernel elements on catering points exhibited a categorical nature. Additionally, a good power-law attenuation relationship was uncovered between the density and distance of catering points, which ultimately revealed the mechanism of preferential attachment in the competition for catering point site selection. Using the results of the agglomeration analysis, a reasonable explanation was provided for the power-law distribution characteristic of the density of catering points, which achieved an organic connection between micro-analysis and macro-characteristic analysis. These findings could provide a reference for the analysis of aggregation characteristics of other urban commercial formats.

Comparative Probabilistic Seismic Hazard Analysis for Sakarya

Sakarya province can be significantly affected by earthquakes on the North Anatolian Fault. Earthquake hazard includes some uncertainties. Earthquake catalog data is needed for probabilistic earthquake hazard calculations. In addition to current catalog information, existing attenuation relationships, including earthquake characteristics for the region, should be developed or their suitability checked. For this purpose, an earthquake hazard analysis was carried out for the Serdivan, Erenler, Adapazarı, and Arifiye districts of Sakarya by using the EMME (Earthquake Model of the Middle East Region) data catalog, which was carried out on a global scale and using the ASK14 model from the NGA-West2 equations. CRISIS software was used for analysis. As a result of the study, it was concluded that the evaluation of ground effects in these regions is an essential requirement.

Physically Based and Empirical Ground Motion Prediction Equations for Multiple Intensity Measures (PGA, PGV, Ia, FIV3, CII, and Maximum Fourier Acceleration Spectra) on Sakhalin Island

In the present study, empirical attenuation relations for multiple ground motion intensity measures (PGA, PGV, Ia, FIV3, CII, and MFAS) were developed for Sakhalin Island (in the far east of Russia). A recorded strong motion dataset was used, making GMPEs applicable in active crustal regions with an earthquake magnitude range of 4–6 and a distance range of up to 150 km. The hypocentral distance was used as a basic distance metric. For the first time in the research, an analytical representation of Arias intensity (Ia) was obtained in the framework of a multi-asperity source model. Asperities are considered as sub-sources of high-frequency incoherent radiation. The physical representation of the attenuation model in our study was based on a stress drop on the asperities and the ratio of the total rupture area to the combined area of asperities. The average stress drop on asperities for the examined earthquakes was approximately 13.4 MPa, and the ratio of the total rupture area to the asperity area was 0.22, which is generally close to similar estimates for crustal earthquakes. The coefficients and statistical scattering of the attenuation models were also analyzed. Moreover, a magnitude scale based on a modified Arias intensity is proposed in the present study. The new magnitude scale has an explicit physical meaning and is characterized by its simplicity of measurement. It is associated with the acceleration source spectrum level and can be successfully used in early warning systems.

Crystal Structure, Electronic Structure, the Density of States, Optical Properties, and Superconducting Transition Temperature of ZrBeSi Crystal under Pressure

Through a rigorous application of first‐principles simulations, it is endeavored to provide a systematic examination of how the crystal structure, electronic structure, density of states, optical properties, and superconducting transition temperature of ZrBeSi are influenced by variations in pressure. The research has shown that pressure can alter the electronic structure and density of states, with a tendency for expansion toward higher energy regions as pressure increases. By manipulating the pressure, both the absorption coefficient and energy loss are sensitive to pressure and exhibit sharp absorption and loss peaks in the UV wavelength region. In addition to the above, the effects of electron–phonon coupling are taken into account and further investigations of the superconducting transition temperature , which is found to be 0.564 K at 0 GPa, are subsequently delved into. Additionally, there exists a quadratic attenuation relationship between the temperature and pressure. Further studies reveal that the decrease of with increasing pressure is a result of the combined effects of the gradual increase in the phonon density of states’ frequency and the flattening of the density of states near the Fermi level. The findings of this study contribute to the understanding of the impact of pressure on the physical properties of materials.

A practical framework for performance-based reliability analysis of subway stations based on a fault–structure combined system

It is necessary to pay particular attention to the uncertainties that exist in an engineering problem to reduce the risk of seismic damage of infrastructures against natural hazards. Moreover, certain structural performance levels should be satisfied during strong earthquakes. However, these performance levels have been only well described for aboveground structures. This study investigates the main uncertainties involved in the performance-based seismic analysis of a multi-story subway station. More than 100 pulse-like and no pulse-like ground motions have been selected. In this regard, an effective framework is presented, based on a set of nonlinear static and dynamic analyses performed by OpenSees code. The probabilistic seismic demand models for computing the free-field shear strain of soil and racking ratio of structure are proposed. These models result in less variability compared with existing relations, and make it possible to evaluate a wider range of uncertainties through reliability analysis in Rtx software using the Monte Carlo sampling method. This work is performed for three different structural performance levels (denoted as PL1–PL3). It is demonstrated that the error terms related to the magnitude and location of earthquake excitations and also the corresponding attenuation relationships have been the most important parameters. Therefore, using a fault–structure model would be inevitable for the reliability analysis of subway stations. It is found that the higher performance level (i.e. PL3) has more sensitivity to random variables than the others. In this condition, the pulse-like ground motions have a major contribution to the vulnerability of subway stations.

Investigating the effect of seismicity on spatial sediment sources and loads using the fingerprinting approach

Elevated soil erosion and suspended sediment loss are some of the most severe environmental problems in the river catchments of Iran. Seismic activity is known to elevate sediment loss and this study investigated sediment sources and loads in the Talar Drainage Basin in Iran, in the context of earthquake frequency and magnitude. A catalogue of earthquakes in the study region was assembled to estimate the expected high-frequency ground motions (i.e., Peak Ground Acceleration (PGA)). The horizontal ground acceleration was estimated using five global and reginal attenuation relationships. To fingerprint sub-basin spatial sediment sources in the study area, two size fractions (<63 μm and 63–125 μm) and 49 geochemical elements were analysed on 30 sediment samples collected from three potential tributary sub-basin spatial sediment sources and 10 target sediment samples collected at the overall basin outlet. Source contributions were estimated using a Bayesian un-mixing model. The estimated relative contributions of the individual spatial sediment sources for both the <63 μm fraction (51.9% (48.6–55.3), 48 % (44.6–51.3), and 0. 1% (0–0.2)) and 63–125-μm fraction (68.2% (66.4–69.8), 31.7% (30.1–33.6), and 0.1 % (0–0.2)) correlated with recorded seismic events. The correlations between sub-basin specific sediment loads and PGA were r = 0.68 for the <63 μm fraction and r = 0.99 for the 63–125 μm fraction. The results demonstrate that seismic activity and ground acceleration can elevate erosivity and erodibility factors. This study supports environmental planners for targeting management to reduce elevated suspended sediment loads and preserve fluvial habitats.

Numerical Modeling of Air-Blast Suppression as a Function of Explosive-Charge Burial Depth

Abstract As a chemical explosion is buried, the mechanism for acoustic wave generation transitions from fully gas-generated at the surface to completely spall-induced at full containment depth. The fully gas-generated and completely spall-induced signals in the acoustic waveform are well described; however, the transition between these two end-members eludes numerical modeling because of the complex phenomena that are involved. The phenomena of crater formation and explosive cloud evolution are simulated using an Eulerian hydrocode that incorporates geomaterials with strength and porosity. Having accurately modeled these phenomena, we can confidently predict the propagation and relative strength of the gas-generated and spall-induced pulses in the recorded acoustic waveform. The numerical predictions agree with observations from the historical Stagecoach experiment as well as modern recordings from the Source Physics Experiment. In particular, the peak pressure p generated by an explosion is initially due to the gas-generated mechanism and decays with scaled depth of burial ds (depth d scaled by the cube-root of explosive yield w1/3) as exp(−ds) but then transitions near a scaled depth of 6 m/ton1/3 to the spall-generated mechanism in which the decay is ds−7/4. This decay form is related to the strong ground-motion attenuation relationship that affects spall strength. These results can improve seismoacoustic inverse models for the explosive source that need to account for the gas-generated and spall-induced signals and their effect on peak pressures and other acoustic signal features.

Spatial Pattern and Intensity Mapping of Coseismic Landslides Triggered by the 2022 Luding Earthquake in China

On 5 September 2022, an Mw 6.6 earthquake occurred in Luding County in China, resulting in extensive surface rupture and casualties. Sufficient study on distribution characteristics and susceptibility regionalization of the earthquake-induced disasters (especially coseismic landslides) in the region has great significance to mitigation of seismic hazards. In this study, a complete coseismic landslide inventory, including 6233 landslides with 32.4 km2 in area, was present through multi-temporal satellite images. We explored the distribution and controlling conditions of coseismic landslides induced by the 2022 Luding event from the perspective of epicentral distance. According to the maximum value of landslide area density, the geographical location with the strongest coseismic landslide activity intensity under the influence of seismic energy, the macro-epicenter, was determined, and we found a remarkable relationship with the landslide distribution and macro-epicentral distance, that is, both the landslide area and number density associatively decreased with the increase in macro-epicentral distance. Then, a fast and effective method for coseismic landslide intensity zoning based on the obvious attenuation relationship was proposed, which could provide theoretical reference for susceptibility mapping of coseismic landslides induced by earthquakes in mountainous areas. Additionally, to quantitatively assess the impact of topographic, seismogenic and lithological factors on the spatial pattern of coseismic landslides, the relationships between the occurrences of coseismic landslides and influencing factors, i.e., elevation, slope angle, local relief, aspect, distance to fault and lithology, were examined. This study provides a fresh perspective on intensity zoning of coseismic landslides and has important guiding significance for post-earthquake reconstruction and land use in the disaster area.

How large peak ground acceleration by large earthquakes could generate turbidity currents along the slope of northern Japan Trench

Deep-sea turbidite has been used to determine the history of occurrence of large earthquakes. Surface-sediment remobilization is a mechanism of the generation of earthquake-induced turbidity currents. However, the detailed mechanism of surface-sediment remobilization caused by earthquake ground shaking is unclear. To understand how high peak ground acceleration (PGA) caused by a large earthquake can remobilize surface sediments, we determined the age of a surface-sediment core recovered from the mid-slope terrace (MST) of the inner slope of the Japan Trench in northern Sanriku to determine turbidites generated by large historical earthquakes and calculate the PGAs of these earthquakes using an empirical attenuation relation commonly used in Japan. Small offsets in radiocarbon ages and excess 210Pb activities between turbidite and hemipelagic muds suggest that the turbidites in the core resulted from surface-sediment remobilization. 137Cs and excess 210Pb chronologies indicate that the three uppermost turbidites in the core are correlated with three large historical earthquakes, namely the 1968 common era (CE) Tokachi-oki, the 1933 CE Showa–Sanriku, and the 1896 CE Meiji–Sanriku earthquakes. Calculation of PGAs for large historical earthquakes along the northern Japan Trench indicates that a PGA of > 0.6 g is necessary for turbidite deposition in the MST basin. This threshold is larger than that reported for central Sanriku and may vary spatially. Moreover, turbidites in the MST deposits are more frequent in the northern Japan Trench than in the central Japan Trench, suggesting that the occurrence of three types of large M8-class earthquakes in the northern Japan Trench might have contributed to the frequent occurrence of large PGAs.

A Risk-Based Framework to Improve a Distribution System’s Resilience against Earthquakes

Earthquakes and other natural disasters have caused significant damages to power systems, indicating the necessity to enhance power system resilience. This paper proposes a risk-based resilience enhancement framework against earthquakes that considers their stochastic nature. The proposed framework supports the decision-making of distribution system operators (DSOs) for retrofitting substation components and underground cables to enhance distribution system resilience. The framework consists of four phases, namely earthquake modeling, vulnerability assessment, risk assessment, and resilience enhancement. An attenuation relationship is used to model the earthquake characteristics. Vulnerability assessment includes the failure probability calculation of substation components and a fault-tree method application to examine the seismic vulnerability of the substation. Conditional value at risk (CVaR) is used to assess the seismic risk, and includes the estimation of repair cost and customer interruption cost due to the damage caused by the earthquake, as well as the power generation cost of the distributed energy resources (DERs) used to meet the demand locally. A modified risk reduction worth (RRW) metric is adopted to determine the optimal retrofitting strategy to enhance resilience. The proposed framework was applied to a real distribution substation to examine the effectiveness of substation component retrofitting for resilience enhancement.

Estimation of Coda Q Wave Attenuation Factors for Northern Iraq

The coda wave decay method was used to estimate the quality factor from the coda wave amplitude decay rate for the broadband seismic stations in northern Iraq using a single back-scattering model. The study aims to calculate the attenuation factor to comprehend the details of the structure of the earth's crust in the study area. The study was conducted using data from the Mesopotamian Network and the Iraqi Meteorological Organization and Seismology from 2007 to 2021. The selected earthquakes have magnitudes ranging from 4 to 6.1 ML and epicentral distances of less than &lt; 100 km. Seventy seven earthquakes were recorded by three stations (SLY1, DHK1, and IKRK). These earthquakes were analyzed at eight center frequencies (1, 2, 3.5, 6, 8, 10, 12, and 16 Hz) and a 30-sec length window by using the Seisan package. The Qc values are computed by the frequency-dependent relationship QC= Q0 f α, where Q0 is QC at 1 Hz and α denotes the degree of frequency dependence. The attenuation relationship of station SLY1 is obtained as QC =88 f 1.02, QC = 90 f 0.97 in the DHK1 station, and QC = 91 f 1.04 in the IKRK station. The comparison of these three stations indicates that attenuation is highest in Sulaymaniyah, followed by Duhok, and then Kirkuk.

On the acoustic attenuation characteristics of sonar detection in the salt-cavern gas storage environment

Aiming at the acoustic attenuation in the salt-cavern environment, this paper established a theoretical relationship of the ultrasonic attenuation in the salt-cavern gas storage, based on the wave equation of the acoustic wave propagating in a non-ideal medium, and considering the specific environment of gas storage, and analyzes how the wall roughness of the gas storage affects the acoustic attenuation. The results show that the inner wall roughness of the salt-cavern gas storage has an effect on the acoustic attenuation. The inner wall surface is at the solid-liquid interface, where the change of the medium will affect the attenuation of the acoustic wave, and the effective reflection coefficient of the inner wall will cause the acoustic wave to attenuate at a lower frequency. On this basis, the characteristics of insoluble particles in the salt-cavern gas storage were also studied, and the main components of different media in salt-cavern cavities and the diameter distribution of different particles were obtained, and an experimental platform was established. According to the experimental results, the roughness of a reflective surface significantly affects the attenuation coefficient of the acoustic wave, and the acoustic wave will suffer two energy losses on a rough wall surface. In addition, the insoluble particles also affect the acoustic attenuation significantly, and scattering attenuation increases with the particle size. The research conclusions provide theoretical basis for the variation characteristics of ultrasonic attenuation with the environmental medium and ultrasonic excitation frequency of the salt-cavern gas storage.

Regional Finite-Fault Source Model for Development of Ground Motion Attenuation Relationship in Sichuan, China

The attenuation relationship of ground motion based on seismology has always been a front subject of engineering earthquake. Among them, the regional finite-fault source model is very important. In view of this point, the general characteristics of regional seism-tectonics, including the dip and depth of the fault plane, are emphasized. According to the statistics of regional seism-tectonics and focal mechanisms in Sichuan, China, and the sensitivity of estimated peak ground acceleration (PGA) attenuation is analyzed, and the dip angle is taken as an average of 70°. Based the statistics of the upper crustal structure and the focal depth of regional earthquakes, the bottom boundary of the sedimentary cover can be used as the upper limit for estimating the depth of upper-edge. The analysis shows that this value is sensitive to PGA. Based on the analysis of geometric relations, the corresponding calculation formula is used, and a set of concepts and steps for building the regional finite-fault source model is proposed. The estimation of source parameters takes into account the uncertainty, the geometric relationship among parameters and the total energy conservation. Meanwhile, a set of reasonable models is developed, which lay a foundation for the further study of regional ground motion attenuation based on seismology.

Preliminary Evaluation of Crustal Medium Parameters in Western China

The establishment of attenuation relation of ground motion is always an important research content in engineering earthquake field. In seismology-based ground motion attenuation relationship and ground motion simulation using the stochastic method, regional parameters are necessary. These parameters involve stress drop Δσ, two segmentation points R1 and R2 of the geometric spreading item, Q0 and η of the inelastic attenuation item and the near-surface high-frequency decay parameter κ0, which reflect the regional crustal medium and site characteristics and have little relation with the earthquake size. In this paper, we take Sichuan, Yunnan and Xinjiang regions in western China as examples and we inverse the parameters for each region by micro-genetic algorithm. The inversion ranges of crustal media parameters in the three regions were determined respectively. Finally, we get the inversion results of every parameters and find that the parameters of the three regions have a great difference.

Demolition by implosion technology of serene towers at Kochi, India

In 2006, Maradu Panchayat granted building permits to Serene builders for two towers without Coastal Zone Management Authority approval, disregarding coastal guidelines. Construction began in 2007, featuring two 16-floor towers with 60 apartments, totalling 200,000 sq ft area. Due to soft topsoil, deep bored cast in-situ piles into dense sand at 45m depth were used as foundations. In 2008, a vigilance probe revealed rule violations. Builders obtained a court-ordered stay, and completed the project in 2010. After a prolonged legal battle, the Supreme Court deemed permissions illegal in 2019, instructing the government to demolish the towers. Controlled implosion with delayed detonation was chosen, despite challenges including proximity to backwaters, nearby houses, and a hotel complex. This paper discusses various preventive measures adopted to control blast impact and field vibration monitoring. Tower demolition occurred on January 11, 2020. Ground vibrations were measured using accelerometers placed on concrete blocks. For Tower 1, peak acceleration ranged from 4.92 to 14.18 m/s², while for Tower 2, it spanned 1.38 to 12.75 m/s². An attenuation relationship for peak particle velocity (PPV) was developed to assess damage potential in the surroundings. Vibrations impacts were found to be insignificant due to short duration and varying frequency content.

The disintegration mechanism analysis of soft rock due to water intrusion based on discrete element method

Though many laboratory tests have been carried out on the effect of water content on the disintegration characteristics of soft rock, there are still relatively few numerical simulations that can well describe this kind of process. Based on the test results obtained by previous relevant research, the two-dimensional unconfined soft rock immersion test was numerically simulated by the discrete element method. The hydration expansion of clay particles is considered in the simulation. The breaking force and residual strength coefficient in MatDEM are selected to characterize the slaking durability of soft rock. Several groups of control sample models were set up, and the effects of crack, clay mineral content, and initial water content on the softening process of rock samples were discussed. The results show that the simulation in this paper is consistent with the process of infiltration and disintegration of soft rock after water immersion in relevant studies. The strength parameters show an exponential attenuation relationship with water content. The breaking force and residual strength coefficient of the complete sample change in a gradient from outside to inside with water content. In addition, the initial crack improves the permeability of soft rock samples and changes the distribution of water content, which has a significant effect on the slaking durability of soft rock. Soft rock samples with high clay mineral content are more prone to plastic softening. The slaking durability of soft rock decreases as the initial water content increases.