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Journal articles on the topic 'Longitudinal seismic wave'
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1
Tohti, Munirdin, Yibo Wang, Wenjiao Xiao, et al. "Numerical simulation of seismic waves in 3-D orthorhombic poroelastic medium with microseismic source implementation." Geophysical Journal International 227, no. 2 (2021): 1012–27. http://dx.doi.org/10.1093/gji/ggab219.
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SUMMARY We have carried out microseismic forward modelling in orthorhombic poroelastic medium. The seismic response to isotropic (ISO) source, double couple (DC) source and compensated linear vector dipole (CLVD) source was solved by finite-difference algorithm in time domain, respectively. We used analytical solution to test our numerical algorithm and find that the match between the analytical solutions and numerical solutions is sufficiently close. We then designed several different models to calculate the seismic response and analyse the effect of medium parameters and source mechanism on the propagation of seismic waves. We observed from the modelling results that ISO source excites two kinds of waves in isotropic medium, which are fast longitudinal wave and slow longitudinal wave, while the DC and CLVD sources excite three kinds of waves in isotropic medium, including a transverse wave in addition to the fast and slow longitudinal waves. All of these three kinds of sources generate four kinds of seismic waves in orthorhombic poroelastic medium. These are two separable transverse waves in addition to the fast and slow longitudinal waves. The fluid viscosity and medium tortuosity has an effect on the propagation of the slow longitudinal wave. The slow longitudinal wave appears in propagating mode under the effect of low fluid viscosity and appears at the source location in a static mode under the effect of high fluid viscosity. The wavefield snapshot of the slow longitudinal wave has a circular shape when the tortuosity is isotropic, whereas it has an oval shape when the tortuosity is anisotropic. As far as the anisotropic parameters are concerned, the anisotropy of the fast longitudinal wave is more sensitive to the value of $\varepsilon ( {{\varepsilon _1},{\varepsilon _2}} )$, while the value of ${\rm{\delta }}( {{{\rm{\delta }}_1},{{\rm{\delta }}_2},{{\rm{\delta }}_3}} )$ has more effect on the anisotropic behaviour of the two separable transverse waves.
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Xiao, Jie Ling, Xian Kui Wei, Ping Wang, and Meng Nan Zhang. "Research on Longitudinal Seismic Response of Continuous Welded Rail on Bridge with High-Pier and Long-Span." Advanced Materials Research 838-841 (November 2013): 1063–68. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1063.
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Longitudinal seismic responses of CWR on bridges with high-piers and long-spans under uniform excitation and traveling wave effect were studied. Results are shown as follows: Under seismic action, rail longitudinal forces near beam joints increase greatly than rail expansion forces (due to beam expansion); Designing CWR on bridges with high-piers and long-spans needs to consider influences of traveling wave effect and wave spreading derection; With the increase of the apparent velocity of seismic waves, rail longitudinal force tends to decrease; We suggest that designing of CWR on bridges crossing high-intensity earthquake zone should consider impact of seismic action, and establish a reasonable check method.
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Galiaskarov, V.A., and Sh.A. Mahmudova. "DETERMINATION OF THE DISTANCE FROM THE EARTHQUAKE EPICENTER TO THE SEISMIC STATION." INNOVATION IN THE OIL AND GAS INDUSTRY 3, no. 3 (2022): 3. https://doi.org/10.5281/zenodo.7466137.
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According to the data of the Republican Center for Seismic Prognostic Monitoring of the Ministry of Emergency Situations on the magnitude at the epicenter of the earthquake, the depth of the earthquake, the distance from the epicenter to the engineering seismometric observation station and the difference in the arrival time of longitudinal P and transverse S seismic waves determined by the seismograms of this station, it is possible to calculate the velocity of the longitudinal P seismic wave. Knowing the velocity of the longitudinal P seismic wave and the time difference between the front of the longitudinal P and transverse S waves, determined by seismograms, it is possible to calculate the distance from the epicenter of the earthquake to the location of the seismometric station.
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Starodub, Yu P., B. Ye Kuplovskyi, and T. M. Gonchar. "GEODYNAMICS." GEODYNAMICS 2(11)2011, no. 2(11) (2011): 287–89. http://dx.doi.org/10.23939/jgd2011.02.287.
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The results of seismic wave field modeling on the cross-section model of the crust (for Drobyshivske gas-condensate field example) were presented. Complicated cut of the crust, resulting geophysical study, represented as a reservoir model. When modeling, seismic wave field features of two-dimensional cross section were taken into account: longitudinal, transverse and exchange waves received on seismograms of longitudinal and transverse vibrations as a result of default distribution of velocities of longitudinal, transverse waves and the density in half-space medium.
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Асланов, Т. Г., and Т. Г. Айгумов. "Simulation of the operation of bottom seismographs using artificial neural networks." MORSKIE INTELLEKTUAL`NYE TEHNOLOGII)</msg>, no. 2(56) (June 9, 2022): 143–48. http://dx.doi.org/10.37220/mit.2022.56.2.019.
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В работе для локализации сейсмических событий предлагается использовать суда в Каспийском море. Используя гидрофон на корабле, можно зафиксировать время прихода гидроакустической волны (продольной волны). Зная параметры водной среды, а также рельеф дна, можно вычислить координаты и время прихода продольной сейсмической волны к границе земной и водной сред. После некоторых преобразований, подав полученное время в нейронную сеть, можно получить информацию о разности времен пробега продольной и поперечной сейсмических волн в указанной точке морского дна. Для обучения нейронной сети, в течении года, на донном сейсмографе, локация которого постоянно меняется, необходимо производить сбор информации о происходящих сейсмических событиях. Для формирования обучающей выборки необходимо собрать информацию о разности времен пробега продольной и поперечной сейсмических волн до каждого наземного и донного сейсмического датчика, о разности времен пробега продольной сейсмической волны до каждого наземного сейсмического датчика, относительно донного сейсмографа, а также координаты донного сейсмографа. На основе математической модели была проверена возможность обучения нейронной сети имитировать информацию по разности времен пробега сейсмических волн на донном сейсмографе при помощи морского судна. Для обучения искусственной нейронной сети использовалась многослойная сеть с 60 скрытыми слоями с функцией активации – сигмоида. В качестве входов в нейронную сеть использовались нормированные разности времен прихода продольной и поперечной сейсмических волн от гипоцентра землетрясения до каждого сейсмического датчика, нормированные разности времен прихода продольной сейсмической волны до каждого наземного сейсмического датчика относительно донного сейсмографа, а также нормированные координаты донного сейсмографа. Таким образом, у нейронной сети всего 37 входов. Выходом искусственной нейронной сети является разность времен прихода продольной и поперечной сейсмических волн до донного сейсмографа. The article proposes using vessels in the Caspian Sea to localize seismic events. Using a hydrophone on the ship, it is possible to record the arrival time of a hydroacoustic wave (longitudinal wave). Knowing the parameters of the aquatic environment, as well as the bottom relief, it is possible to calculate the coordinates and time of arrival of a longitudinal seismic wave to the boundary of terrestrial and aquatic environments. After some transformations, by feeding the received time into the neural network, it is possible to obtain information about the difference in the travel times of longitudinal and transverse seismic waves at the specified point of the seabed. To train a neural network, during the year, on a bottom seismograph, the location of which is constantly changing, it is necessary to collect information about ongoing seismic events. To form a training sample, it is necessary to collect information about the difference in the travel times of the longitudinal and transverse seismic waves to each ground and bottom seismic sensor, about the difference in the travel times of the longitudinal seismic wave to each ground seismic sensor, relative to the bottom seismograph, as well as the coordinates of the bottom seismograph. On the basis of a mathematical model, the possibility of training a neural network to simulate information on the difference in the travel times of seismic waves on a bottom seismograph using a marine vessel was tested. To train an artificial neural network, a multilayer network with 60 hidden layers with a sigmoid activation function was used. The inputs to the neural network were normalized differences in the arrival times of longitudinal and transverse seismic waves from the earthquake hypocenter to each seismic sensor, normalized differences in the arrival times of the longitudinal seismic wave to each ground seismic sensor relative to the bottom seismograph, as well as normalized coordinates of the bottom seismograph. Thus, the neural network has only 37 inputs. The output of an artificial neural network is the difference in the arrival times of longitudinal and transverse seismic waves to the bottom seismograph.
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Aslanov, T. G. "Recovering Seismic Sensor Data on Arrival Time Differences for Longitudinal and Transverse Seismic Waves." Herald of the Bauman Moscow State Technical University. Series Instrument Engineering, no. 3 (140) (September 2022): 4–17. http://dx.doi.org/10.18698/0236-3933-2022-3-4-17.
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We developed a method for seismic sensor data recovery and simulated seismic sensor operation using artificial neural networks. We selected two parameters to train the artificial neural network on: the time between seismograph recordings of longitudinal (primary) and transverse (secondary) seismic waves, as well as the time between primary seismic wave recordings by two seismographs located at a certain distance from each other. We used data on 2636 earthquakes that occurred in 2020 in the Republic of Dagestan for our seismograph data recovery. The existing 19 seismic stations recorded less than 60 % of the total number of earthquakes. To recover seismic data, we trained the neural network twice for each seismic sensor, the first time involving zero time differences regarding seismic wave arrival at seismographs that did not record the time, and the second time involving time differences recovered from the results of training the neural network for the first time. Times between seismic wave recordings with known data were used as inputs to train the artificial neural network, while time differences to be determined were designated as outputs. The trained neural network displays a correlation coefficient related to real time intervals between seismograph recordings of seismic waves that exceeds 0.99919. The paper provides root-mean-square error plots of the neural network operation by epochs of its training, plots demonstrating how training results calculated by the neural network matchthe initial data, and histograms of neural network operation errors
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Devaney, A. J., and M. L. Oristaglio. "A plane‐wave decomposition for elastic wave fields applied to the separation of P‐waves and S‐waves in vector seismic data." GEOPHYSICS 51, no. 2 (1986): 419–23. http://dx.doi.org/10.1190/1.1442102.
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We describe a method to decompose a two‐dimensional (2-D) elastic wave field recorded along a line into its longitudinal and transverse parts, that is, into compressional (P) waves and shear (S) waves. Separation of the data into P-waves and S-waves is useful when analyzing vector seismic measurements along surface lines or in boreholes. The method described is based on a plane‐wave expansion for elastic wave fields and is illustrated with a synthetic example of an offset vertical seismic profile (VSP) in a layered elastic medium.
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Wang, Qiyao, Yawu Yang, Hongquan Teng, and Yifei He. "Longitudinal Seismic Response of Metro Tunnels Crossing a Fault with Multi-Slip Surfaces." Buildings 14, no. 1 (2024): 207. http://dx.doi.org/10.3390/buildings14010207.
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There are multiple seismic fault zones near Xi’an in China, among which the Li Piedmont Fault has multiple slip surfaces. A 3D finite element dynamic Soil–Fault–Tunnel model was established based on the engineering background of the Xi’an Metro tunnel orthogonally crossing the Li Piedmont Fault. The input seismic loads used the Chi-Chi, El-Centro, and artificial seismic waves, and the latter was artificially synthesized based on seismic conditions and site conditions of actual engineering. The Chi-Chi seismic wave with larger PGV/PGA and wider acceleration-sensitive area is a near-field seismic wave, while the others are far-field seismic waves. The seismic loads were transformed into the equivalent nodal force on the boundary nodes of the model, and nonlinear dynamic calculation was carried out to obtain the longitudinal seismic response of the structure. The main results show that the fault amplifies the seismic response of the tunnel, and the tunnel at the position of the fault slip surfaces is more vulnerable to failure, especially near the slip surface between the hanging wall and the fault, where the maximum acceleration, soil pressure, and internal force of the tunnel structure occur. In addition, the seismic response of the tunnel and soil caused by near-field seismic motion is significantly stronger than that caused by far-field seismic motion.
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Selim, Mahmoud M., and Taher A. Nofal. "A Mathematical Model of Longitudinal Waves Incident at a Free Surface of a Pre-Stressed Dissipative Half-Space." Mathematics 8, no. 11 (2020): 2011. http://dx.doi.org/10.3390/math8112011.
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The aim of this work is to study the behavior of reflection of a longitudinal wave at a free surface of dissipative half-space under the effects of compressive initial stresses. When a longitudinal wave is incident on the free surface of an elastic dissipative half-space, two damped waves (Primarywaves and secondary waves are reflected. Among of these waves, P-waves are affected by compressional initial stresses. The governing equation and corresponding closed-form solutions are derived based on Biot’s incremental deformation theory. The equations of motion are solved analytically and the influence of initial stress parameter on the reflection coefficient of P-wave incidents at the free surface of dissipative half-space is studied in detail. Numerical computations are performed for actual Earth crust and the results analyzing the incident of longitudinal waves are discussed and presented graphically. The analytical solutions and numerical results reveal that the compressive initial stress parameter has notable effects on the reflection coefficient of longitudinal wave incidents on the free surface of dissipative medium. In addition, it has been observed that the presence of compressive initial stresses increases the phase velocity of the longitudinal waves. To the authors’ best knowledge, effects of compressive initial stresses on the reflection coefficients of the incident longitudinal wave on a free surface of dissipative half-space have not been studied before. Since the actual Earth is subject to initial stresses due to different resources, understanding the influences of compressive initial stresses on the reflection coefficient of a longitudinal wave helps seismologists and earthquake engineers to get accurate results of the reflection coefficients of seismic waves propagation in the Earth. Thus, the present study would be useful for seismology and earthquake engineering fields and further study about the nature of seismic waves.
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Li, Yong Bo, Hong Ru Zhang, and Chun Feng Li. "Longitudinal Seismic Response Analysis of MSSS Bridge in Qinghai-Tibet Railway." Advanced Materials Research 250-253 (May 2011): 2667–71. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2667.
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This paper presents the results of seismic behavior analysis of a multi-span simply supported (MSSS) bridge in Qinghai-Tibet Railway. The main goal is to examine the effects of frozen soil condition and wave passage on seismic behavior of MSSS Bridge. A 2D FE model was established by ANSYS software in order to evaluate the effects of modeling, in which bearings and pounding effects were also considered. Results indicate that frozen soil condition has an important effect on the seismic response in longitudinal direction; wave passage can influence the seismic response of MSSS Bridge within a certain range of seismic wave travelling velocity.
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Zhao, Huiling, Yuheng Ma, and Xupeng Yao. "Dynamic Response of Curved Tunnels under Vertical Incidence of Transversal SV Waves." Shock and Vibration 2023 (April 25, 2023): 1–15. http://dx.doi.org/10.1155/2023/8561647.
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Long tunnels often have curved sections when alignment designs are influenced by topography, adverse geology, and environmental factors. When the transversal SV wave is incident vertically, the curved section of the tunnel is subject to a connection between longitudinal and transversal loads, which are asymmetrical about the tunnel longitudinal axis. Compared to straight tunnels, curved tunnels are more complex in terms of forces and deformations and may become a key control section limiting the seismic safety of curved tunnels. To investigate the seismic response of curved tunnels, numerical simulations of curved tunnels with different radii of curvature under transversal SV seismic waves were carried out in this study. Local artificial boundaries were programmed and used for the 3D rock tunnel interaction system model to simulate semi-infinite rock and to eliminate fake reflections of seismic waves on local boundaries. The results show that longitudinal deformation and cross-sectional deformation occurred simultaneously in curved tunnels when the transversal SV wave was incident vertically. As the curvature increased, the longitudinal deformation of the curved tunnel increased. The cross-section of the tunnel was in oblique compression, and the cross-sectional internal force showed significant asymmetry. When the radius of curvature was 250 m, the difference in bending moment between the left and right haunch was 35.2%. These characteristics differ from those of straight tunnels and should be paid attention in the seismic design of curved tunnels.
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Solovyev, V. M., A. S. Salnikov, V. S. Seleznev, T. V. Kashubina, and N. А. Galyova. "Deep seismic structure of the Sikhote-Alin folded system according to the GSZ (in the alignment of the reference profile 8-DV)." Interexpo GEO-Siberia 2, no. 2 (2022): 137–44. http://dx.doi.org/10.33764/2618-981x-2022-2-2-137-144.
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The results of deep seismic studies on the Sikhote-Alin fragment of the reference geophysical profile 8-DV are presented. A deep seismic section of the Earth's crust and upper mantle with the velocity distribution of longitudinal waves is constructed. The complex dislocated structure of a powerful Paleozoic sedimentary complex within the Middle Amur Depression has been established. Crystalline rocks with longitudinal wave velocities of 6.0-6.2 km/s lie at depths from 8 to 13 km in different parts of the Middle Amur Depression and 4-6 km within the Sikhote-Alin orogenic complex. In the entire thickness of the Earth's crust of the Sikhote-Alin fragment of the 8-DV profile, the velocities of longitudinal waves are 6.3-6.35 km/s. The thickness of the Earth's crust varies from 32 to 35 km. Along the Mohorovichich boundary, the velocity of longitudinal waves in general is 7.8-8.3 km/s. The correlation of the identified anomalies according to P-wave data with structural-tectonic zones was carried out.
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Sultanov, Karim Sultanovich, and Nikolai Ivanovich Vatin. "Wave Theory of Seismic Resistance of Underground Pipelines." Applied Sciences 11, no. 4 (2021): 1797. http://dx.doi.org/10.3390/app11041797.
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The object of the research is an underground straight horizontal pipeline subjected to seismic impact. The research method was analytical. The results were compared with the experimental results of other authors and computer calculations. It was shown that the main disadvantage of the dynamic theory of seismic resistance of underground pipelines is the neglect of the dynamic stress state in soil under seismic wave propagation. The next drawback of the dynamic theory is an inaccurate, approximate accounting for the displacement of the soil medium to which the underground pipeline is embedded. The complete interaction process includes the stages of nonlinear changes in the interaction force (the friction force) by manifesting its peak value and the Coulomb friction. The contact layer of soil undergoes shear deformations until complete structural destruction of the soil contact layer. The interaction force is the friction force, and its peak value does not appear. The seismic resistance of underground pipelines should be considered based on the theory of propagating seismic waves in a soil medium and the interaction of seismic waves with underground pipelines, i.e., based on the wave theory of seismic resistance of underground pipelines. A one-dimensional coupled problem of seismic resistance of underground pipelines under seismic impacts was posed based on the wave theory. An algorithm and a program for the numerical solution of the stated wave problems were developed using the method of characteristics and the method of finite differences. An analysis of the laws of interaction of underground pipelines with soil under seismic influences shows that it is necessary to use in the calculations the laws of interaction that account for the complete interaction processes observed in experiments. The analysis of the obtained numerical solutions and the posed coupled problems of the wave theory of seismic resistance of underground pipelines show the occurrence mechanisms of longitudinal stresses in underground pipelines under seismic influences. The results of calculations stated that an account for the dynamic stress normal to the underground pipeline’s outer surface leads to multiple increases in longitudinal stress in the underground pipeline. This multiple increase is due to the transformation of the interaction force into an active frictional force, resulting from a greater strain in soil than the one in the underground pipeline. Based on the analysis results, a theory of the seismic wave propagation process in an underground pipeline and surrounding soil was proposed.
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Tian, Zhong-ye, and Meng-lin Lou. "Traveling Wave Resonance and Simplified Analysis Method for Long-Span Symmetrical Cable-Stayed Bridges under Seismic Traveling Wave Excitation." Shock and Vibration 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/602825.
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The seismic responses of a long-span cable-stayed bridge under uniform excitation and traveling wave excitation in the longitudinal direction are, respectively, computed. The numerical results show that the bridge’s peak seismic responses vary significantly as the apparent wave velocity decreases. Therefore, the traveling wave effect must be considered in the seismic design of long-span bridges. The bridge’s peak seismic responses do not vary monotonously with the apparent wave velocity due to the traveling wave resonance. A new traveling wave excitation method that can simplify the multisupport excitation process into a two-support excitation process is developed.
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Wu, Hui Jun, and Wen Liang Qiu. "Dynamic Performance and Seismic Analysis of Tied Arch Bridge." Advanced Materials Research 446-449 (January 2012): 1119–22. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.1119.
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Based on the anti-seismic research achievements of tired arch bridge at home and abroad, taking River City Bridge in Jilin as an example, a finite element model is established for dynamic performance analysis by general finite element software midas civil. Natural vibration characteristics of tied arch bridge are calculated as a basis for further dynamic calculation. Firstly, choose appropriate seismic waves according to the geological data. Then perform the dynamic response analysis of this bridge under different loading cases. Dynamic responses of this bridge under longitudinal and transverse seismic waves are studied respectively, and the influence of vertical seismic wave is also considered. It is shown that the influence on seismic response of vertical seismic waves is very obvious. The vertical seismic waves should be considered while doing seismic design of tied arch bridges.
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Xu, Hao, Xinjiang Yu, Fei Cheng, Yuxi Ma, Jialiang Li, and Xiaohuan Jiang. "Effects of Earth–Rock Dam Heterogeneity on Seismic Wavefield Characteristics." Energies 16, no. 5 (2023): 2423. http://dx.doi.org/10.3390/en16052423.
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Earth–rock dams are typical soil–rock mixtures with high heterogeneity. Mastering the effect of dam heterogeneity on seismic wavefields is the premise of accurately detecting hidden risks in dams. In this paper, based on the soil–rock mixture characteristics of actual dams, a soil–rock mixture model that can reflect the heterogeneity of dams is established through local segmentation and reassignment of random disturbances. The influence of local area size on model heterogeneity is described. The seismic wavefield in a soil–rock mixture dam is numerically simulated through a staggered-grid finite-difference algorithm with second-order accuracy in time and sixth-order accuracy in space. Then, the effect of dam heterogeneity on effective wavefields is analyzed. The results show that the heterogeneity of the earth–rock dam can lead to scattered waves in the seismic wavefield, and the scattered waves are mainly generated by Rayleigh surface waves. In the seismic record, scattered waves with strong energy appear in the region below the surface waves. The scattered wave energy is weak and close to that in the homogeneous media in the region above the surface waves. As the rock content in the dam increases, the scattering of seismic wavefields and the energy of scattered waves weaken gradually. The scattered waves generated by the heterogeneity of the dam significantly impact the reflected longitudinal wave and converted wave but, affect the reflected shear wave less. The numerical simulation results are consistent with the acquired seismic wavefield from the field test, proving the effectiveness of the numerical simulation for the seismic wavefield propagation characteristics of the earth–rock dam.
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Miao, Fengyang, Weiguo Li, Jianguo Xu, Zhihao Chen, and Xiaoyu Feng. "Dynamic Response Analysis of Buried Drainage Pipes for Polymer Grouting Trenchless Rehabilitation under the Traveling Wave Effect." Advances in Civil Engineering 2022 (September 29, 2022): 1–15. http://dx.doi.org/10.1155/2022/2129573.
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The polymer grouting nonexcavation repair technology has been widely used in the repair of underground pipeline leaks, but the seismic response to the polymer repair pipeline is currently using a consistent excitation of seismic input without considering the influence of the traveling wave effect. This paper establishes the longitudinal and transverse vibration models of the polymer grout repair pipeline considering the traveling wave effect based on the elastic foundation beam theory. The seismic input uses artificially generated random seismic waves and solves the differential equations for pipeline vibration to carry out seismic response analysis of long-buried pipelines under three conditions: normal, vacant, and polymer grouting repair. The results show that after considering the traveling wave effect, the reaction of each measuring point on the pipeline has obvious phase characteristics, and the waveform of the distant measuring point has an obvious hysteresis phenomenon; the seismic wave velocity has a great influence on the deformation of the pipeline, and the displacement amplitude of the pipeline increases with the increase of the seismic wave velocity. The peak of pipeline displacement after vacancy will increase by 100%∼300% more than normal, while the difference in pipeline deformation after high polymer grouting is about 25% compared with normal, which means that the bottom vacant will have a great influence on pipeline deformation, and high polymer repair can restore the pipeline mechanical properties to normal levels.
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Wang, Cheng, and Yan Xu Wang. "Dynamic Analyses of a Self-Anchored Suspension Bridge under Seismic Excitations." Applied Mechanics and Materials 580-583 (July 2014): 1687–91. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1687.
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The seismic response of the Wusong bridge was analyzed though the response spectrum method and the time-history method by adopting the MIDAS/CIVIL. The analysis results show that the longitudinal displacement of the main girder is much larger under longitudinal seismic input, so some inhibiting device or dampers should be used to avoid impacting. There is not coupling between longitudinal and lateral seismic excitations, while the seismic response of moment and shear force at the bottom of the main tower is much larger. On the contrary the seismic response of main beam and the main cable should be calculated under the longitudinal and vertical seismic excitations because of the coupling between the both of them. Furthermore, the artificial seismic wave fitting standard response spectrum was generated to conduct the time-history analysis and the results are much larger than the results from the response spectrum method.
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Zhang, Qi, Mi Zhao, Jingqi Huang, Xiuli Du, and Guoliang Zhang. "A 2.5D Finite Element Method Combined with Zigzag-Paraxial Boundary for Long Tunnel under Obliquely Incident Seismic Wave." Applied Sciences 13, no. 9 (2023): 5743. http://dx.doi.org/10.3390/app13095743.
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Seismic waves propagation with an oblique angle to the tunnel axis will cause asynchronous tunnel motions and have a significant effect on the axial response. A high-precision 2.5D finite element method is established in the frequency domain to simulate the 3D seismic response of the tunnel. This method avoids the disturbance caused by the truncation of the tunnel in the longitudinal direction. Meanwhile, a 2.5D zigzag-paraxial boundary is derived to further improve the calculation efficiency of the 2.5D finite element model. Moreover, by combining the 2.5D finite element method, 2.5D zigzag boundary condition and seismic motion input methods, an obliquely incident substructure method for plane seismic waves is built by converting the plane seismic wave into equivalent nodal forces. The proposed 2.5D finite element method is verified by comparing with a reference solution. Finally, the 2.5D finite element method is applied to study the seismic response of the long lined tunnel. Parameter analyses illustrate that the wave propagation effect to the tunnel axis has a non-negligible influence on the axil deformation of long tunnels.
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Pacheco, D., E. D. Mercerat, F. Courboulex, L. F. Bonilla, A. Laurendeau, and A. Alvarado. "Profiling the Quito basin (Ecuador) using seismic ambient noise." Geophysical Journal International 228, no. 2 (2021): 1419–37. http://dx.doi.org/10.1093/gji/ggab408.
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SUMMARY Quito, the capital of Ecuador, with more than 2.5 M inhabitants, is exposed to a high seismic hazard due to its proximity to the Pacific subduction zone and active crustal faults, both capable of generating significant earthquakes. Furthermore, the city is located in an intermontane piggy-back basin prone to seismic wave amplification. To understand the basin’s seismic response and characterize its geological structure, 20 broad and medium frequency band seismic stations were deployed in Quito’s urban area between May 2016 and July 2018 that continuously recorded ambient seismic noise. We first compute horizontal-to-vertical spectral ratios to determine the resonant frequency distribution in the entire basin. Secondly, we cross-correlate seismic stations operating simultaneously to retrieve interstations surface-wave Green’s functions in the frequency range of 0.1–2 Hz. We find that Love waves travelling in the basin’s longitudinal direction (NNE–SSW) show much clearer correlograms than those from Rayleigh waves. We then compute Love wave phase-velocity dispersion curves and invert them in conjunction with the HVSR curves to obtain shear-wave velocity profiles throughout the city. The inversions highlight a clear difference in the basin’s structure between its northern and southern parts. In the centre and northern areas, the estimated basin depth and mean shear-wave velocity are about 200 m and 1800 ms−1, respectively, showing resonance frequency values between 0.6 and 0.7 Hz. On the contrary, the basement’s depth and shear-wave velocity in the southern part are about 900 m and 2500 ms−1, having a low resonance frequency value of around 0.3 Hz. This difference in structure between the centre-north and the south of the basin explains the spatial distribution of low-frequency seismic amplifications observed during the Mw 7.8 Pedernales earthquake in April 2016 in Quito.
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Yao, Erlei, Yu Rao, Meishan Liu, Zhifang Liu, and Ang Cao. "Study on the Seismic Response of a Water-Conveyance Tunnel Considering Non-Uniform Longitudinal Subsurface Geometry and Obliquely Incident SV-Waves." Applied Sciences 14, no. 11 (2024): 4398. http://dx.doi.org/10.3390/app14114398.
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The longitudinal seismic response characteristics of a shallow-buried water-conveyance tunnel under non-uniform longitudinal subsurface geometry and obliquely incident SV-waves was studied using the numerical method, where the effect of the non-uniform longitudinal subsurface geometry due to the existence of a local one-sided rock mountain on the seismic response of the tunnel was focused on. Correspondingly, a large-scale three-dimensional (3D) finite-element model was established, where different incidence angles and incidence directions of the SV-wave were taken into consideration. Also, the non-linearity of soil and rock and the damage plastic of the concrete lining were incorporated. In addition, the wave field of the site and the acceleration response as well as damage of the tunnel were observed. The results revealed the following: (i) a local inclined subsurface geometry may focus an obliquely incident wave due to refraction or total reflection; (ii) a tunnel in a site adjacent to a rock mountain may exhibit a higher acceleration response than a tunnel in a homogeneous plain site; and (iii) damage in the tunnel in the site adjacent to a rock mountain may appear in multiple positions, and the effect of the incidence angle on the mode of compressive deformation and damage of the lining is of significance.
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Liu, Ai Rong, and Yong Lin Pi. "Seismic Response of Long Span Continuous Rigid-Framed Steel Arch Bridge." Key Engineering Materials 763 (February 2018): 1087–94. http://dx.doi.org/10.4028/www.scientific.net/kem.763.1087.
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This paper investigates seismic responses of Xinguang Bridge, a 3-span continuous rigid-frame and steel-truss arch bridge. Earthquake excitation input is a key issue for the seismic analysis. This paper uses a finite element method to study the traveling wave effect on Xinguang Bridge and its interaction with the dynamic properties of the bridge under the condition of two steps and two levels probability. The seismic response of the bridge under the coincident earthquake excitation is also analyzed. Comparisons show that the seismic response of the long-span bridge by considering the traveling wave effect is much different from that under consistent earthquake excitation. The influence of the shear wave speed on the seismic response of the long span continuous bridge is also explored and the shear wave speed is found to greatly affect the wave shape and magnitude of the time-history of the longitudinal displacement at the crown of the main arch of the bridge. It is concluded that traveling wave effect and shear wave speed of ground have significant influences on the seismic response of the long span continuous rigid-framed and steel-truss arch bridge.
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Porębski, Krzysztof, Eugeniusz Koziarz, Arkadiusz Anderko, et al. "Recognition of gasogeodynamic zones in the rock mass using seismic tomography in Rudna copper ore mine." E3S Web of Conferences 66 (2018): 01012. http://dx.doi.org/10.1051/e3sconf/20186601012.
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In this work, the results of four seismic tomography surveys are presented. The research was conducted to identify the zones exposed to the threat of gas and rock outburst. The changes to the dolomite layer stiffness in the mining excavation roofs were analyzed. The surveys were conducted in the Rudna copper ore mine in the field of XXVIII/1. The research area was about 0.21 km2. The seismic waves were generated by a small amount of explosive material (100 - 300 g) located and installed in short blast holes (1.5 - 2.0 m). The processing and the interpretation of the measurement data did not cause serious problems due to the more favourable elastic properties of the dolomite layer compared to the adjacent anhydrite and sandstone layers. As a result, the maps of parameters like the longitudinal wave velocity (P-wave), the shear wave velocity (S-wave), and the ratio of the Pwave velocity to S-wave velocity and the dynamic Young modulus were estimated. The results showed that the changes in the seismic parameters were relatively small over most of the research area. This may be evidence of the minor effects of gas and rock outbursts.
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Bschorr, Oskar, and Hans-Joachim Raida. "One-Way Wave Equation Derived from Impedance Theorem." Acoustics 2, no. 1 (2020): 164–71. http://dx.doi.org/10.3390/acoustics2010012.
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The wave equations for longitudinal and transverse waves being used in seismic calculations are based on the classical force/moment balance. Mathematically, these equations are 2nd order partial differential equations (PDE) and contain two solutions with a forward and a backward propagating wave, therefore also called “Two-way wave equation”. In order to solve this inherent ambiguity many auxiliary equations were developed being summarized under “One-way wave equation”. In this article the impedance theorem is interpreted as a wave equation with a unique solution. This 1st order PDE is mathematically more convenient than the 2nd order PDE. Furthermore the 1st order wave equation being valid for three-dimensional wave propagation in an inhomogeneous continuum is derived.
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Chen, Baokui, Yujie Du, Yan Shi, and Li Fan. "Seismic Analysis of Isolated Continuous Bridge considering Influence of Seawater and Site Condition." Shock and Vibration 2021 (August 23, 2021): 1–17. http://dx.doi.org/10.1155/2021/7599715.
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The effects of seawater and site conditions on the seismic response of the isolated continuous girder bridge are evaluated in this study. The seawater-muddy soil-isolated bridge coupling model is built in the dynamic analysis software ADINA, and the external seismic wave input is realized by the seismic wave motion analysis program. The influences of seawater and muddy soil on the seismic response of isolated continuous girder bridges are determined by comparing different offshore site models. The results indicated that the seawater and the muddy soil magnify the displacement of the seabed. The existence of seawater increases the longitudinal relative displacement of piers by 20%–40% but has limited influence on the bending moment and shear force of piers. The muddy soil can increase the longitudinal relative displacement and internal force of the piers remarkably. Moreover, the displacement of bridge bearings increases significantly under the combined influence of muddy soil and seawater. In the seawater-muddy soil-isolated bridge coupling model, the seawater and site condition can influence the seismic performance of sea-crossing bridges obviously.
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Shen, Xuzhang, YoungHee Kim, Teh-Ru Alex Song, and Hobin Lim. "Data-oriented constraint on the interpretation of S receiver function and its application to observations of seismic discontinuities in the lithosphere–asthenosphere system." Geophysical Journal International 219, no. 1 (2019): 496–513. http://dx.doi.org/10.1093/gji/ggz316.
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SUMMARY This paper aims to improve the robustness of interpretation in the S receiver function (SRF), a technique commonly used to retrieve forward scattering of S-to-P converted waves (Sdp) originated from the lithosphere–asthenosphere system (LAS) beneath the stations. Although the SRF does not suffer interferences from backward scattering waves such as the first multiples from the Moho, one major drawback in the method is that Sdp phases can interfere with P coda waves and it is conceivable that these signal-generated noise may be misinterpreted as Sdp phase from the LAS beneath seismic stations. Through systematic analysis of full-waveform synthetics and SRFs from catalogued source parameters, we find that the strong P coda waves before the S wave in the longitudinal-component waveforms result in unwanted signal-generated noise before the S wave in the synthetic SRFs. If the mean amplitude of SRFs after the S wave is large, dubious signal-generated noise before the S arrival are strong as well. In this study, we honor the level of these unwanted signal-generated noise and devise data-oriented screening criteria to minimize the interference between P coda waves and genuine S-to-P converted waves. The first criterion is LQR, a direct measure of the amplitude ratio between longitudinal P coda waves and radial S wave in the waveform data. The second criterion is AMP, the amplitude of SRFs after the S arrival. We illustrate that these criteria effectively measure the energy level of mantle waves such as the SP wave. With synthetics and real data, we demonstrate the effectiveness of LQR and AMP criteria in minimizing these unwanted signal-generated noise in the stacked SRFs down to 1–2 per cent, improving detection threshold and interpretation of Sdp phases from seismic discontinuities in the LAS.
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Diao, Aimin, Guangli Cheng, and Zeming Wang. "On the Dispersive Characteristics of Shallow Water Seismic Waves Excited by Air Gun Sound Source in Shallow Water." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 37, no. 4 (2019): 724–29. http://dx.doi.org/10.1051/jnwpu/20193740724.
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In order to study the dispersion characteristics of seabed seismic waves excited by acoustic sources in shallow water, the sound field at liquid-solid interface is derived based on the wave equation firstly, which results demonstrate that the longitudinal wave and transversal wave are not dispersive, while the Scholte wave is normal dispersive. Then, the numerical simulation is carried out on the sound field at the liquid-solid interface excited by the air gun sound source based on high-order staggered grid finite difference method, which results demonstrate that the dispersion phenomenon of Scholte waves is observed and the theoretical analysis results were verified. Finally, the data of experiment in the sea are analyzed based on the transformation, and the dispersion curve of Scholte wave is finely extracted.
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Tuladhar, Raju, and Walter H. Dilger. "Effect of support conditions on seismic response of cable-stayed bridges." Canadian Journal of Civil Engineering 26, no. 5 (1999): 631–45. http://dx.doi.org/10.1139/l99-021.
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The seismic response of a cable-stayed bridge is the result of the interaction between the input earthquake characteristics and the bridge properties like mass, stiffness, and support conditions. The support type used for the deck at the towers of cable-stayed bridges is one of the important parameters that greatly influences the seismic response of the bridge. This is demonstrated in the present paper by study of the change in modal characteristics and seismic response of two cable-stayed bridges for different types of the support conditions. The first bridge has concrete towers and a steel deck with a 371 m main span, and the second bridge also has concrete towers, but a composite deck with a 465 m main span. The study shows that elastic supports for the deck at the towers give very low deck displacements and deck bending moments compared to pinned or fixed connections. Roller supports produce low tower base shear and base moment but not necessarily a low response for the bridge as a whole. Roller supports also cause the bridge to have very low first longitudinal direction mode frequency; this indicates that the bridge is very flexible in the longitudinal direction. A study of the effect of variation of the longitudinal stiffness of the elastic deck supports shows that it strongly influences the first few longitudinal direction modes, but not the symmetric or higher modes. The study also shows that the seismic response of the bridge is highly influenced by the variation of the support stiffness for some earthquakes like 1940 El Centro earthquake, but to a lesser degree for others. Wave propagation effects were also studied for different support conditions of the bridge. It is observed that the seismic response shows a higher degree of variation with the changing wave velocities when the bridge deck has pinned or fixed supports, and that the change in the bridge response with the wave velocities is not very pronounced when the bridge deck has elastic or roller supports. For the first bridge, the critical responses were observed at very low wave velocities, and for the second bridge, the uniform motion case caused the critical response of the bridge at many locations.Key words: cable-stayed bridges, support conditions, seismic response, wave propagations.
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Ryashchenko, T. G., E. A. Maslov, E. V. Bryzhak, T. A. Kornilova, Y. V. Vashestyuk, and A. Yu Bolotnev. "Engineering-geological assessment of rocky soils based on the analysis of the collection of Albazinskoye deposit samples." Earth sciences and subsoil use 45, no. 2 (2022): 197–210. http://dx.doi.org/10.21285/2686-9993-2022-45-2-197-210.
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The article deals with the engineering-geological assessment of the rocky soils of the Albazinskoye deposit located in the north of the Khabarovsk Territory, Russia conducted on the example of the analysis of the collection of samples of various petrographic types of certain geological formations. The purpose of the research is to implement a specially developed complex methodological scheme including an optical method (analysis of thin rock sections), measurement of seismic (surface and through sounding of samples to determine longitudinal seismic wave velocity), strength (vertical compression and tension) and physical (density and water absorption) properties. Using the obtained data, a comparative analysis of samples is performed based on the results of seismic, strength and physical properties taking into account petrographic information. Anisotropy in terms of seismic and strength properties is established. Using a cluster analysis program, the correlation coefficients between property indicators are determined. On example of the materials of the collection, it is shown that the differences in the velocity of longitudinal seismic waves and strength are determined by the textural-structural features and composition of rocky soils, which are studied at the micro level.
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Luo, Zhanyou, Yongheng Deng, Baoping Zou, Jianfeng Zhu, Mingyao Jiang, and Kuangqin Xie. "Study on Field Test and Seismic Performance of MJS Joint Microdisturbance Reinforcement on Existing Tunnel." Shock and Vibration 2021 (September 25, 2021): 1–9. http://dx.doi.org/10.1155/2021/7709050.
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Metro Jet System (MJS) joint microdisturbance reinforcement is often adopted to strengthen and remediate existing tunnels that are severely deformed by under-construction peripheral works, but analysis related to the reinforcement system of tunnel under consideration of seismic effects is insufficient at present. In this work, a field test of MJS joint microdisturbance reinforcement system of existing tunnels was conducted on the basis of a subway tunnel deformation reinforcement project. Then, a numerical simulation study of the seismic dynamic response of reinforcement system was performed in combination with seismic wave direction and intensity. Results show that the MJS joint microdisturbance reinforcement measures can effectively reduce the settlement and horizontal radial convergence deformation of the tunnel. The seismic longitudinal wave significantly affects the vertical displacement of the tunnel, and the seismic-induced vertical displacement of the tunnel increases with the rise in seismic intensity. The seismic transverse wave significantly affects the horizontal radial convergence deformation of the tunnel, and the seismic-induced horizontal radial convergence deformation of the tunnel increases with the rise in seismic intensity. The antiseismic property of MJS joint microdisturbance reinforcement measures on the existing tunnel is not obvious.
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Заславский, Юрий Михайлович, та Владислав Юрьевич Заславский. "О рассеянии релеевских и продольных сейсмических волн на локальной неровности грунта". Computational Continuum Mechanics 17, № 2 (2024): 194–201. http://dx.doi.org/10.7242/1999-6691/2024.17.2.18.
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A three-dimensional (3D) numerical simulation of scattering of seismic surface Rayleigh and longitudinal waves propagating through the ground, the density and elasticity of which are typical of geomedium. At the soil boundary, there is local unevenness in the form of a hollow hemispherical notch (a truncated sphere). The dependence of the direction of the scattering field on the type of inhomogeneity is shown. From literature it is known that in the transition to another type of heterogeneity, for instance, to covering the boundary with a thin inert (massive) layer in the form of a circle, the forward scattering occurs. A pulsed mode of inhomogeneity probing is considered. As an emitter, it is proposed to use a short pulse source, e.g., a hydroacoustic emitter, or something similar - a pulsating monopole, shallowly immersed under the free boundary. This leads to the generation of such elastic waves as the surface Rayleigh and back-reflected longitudinal waves, which are usually recorded using an array of seismic receivers installed on the free boundary according to the grid pattern. The spatial amplitude distribution of the wave field is analyzed in the vertical (at the center of the inhomogeneity) and horizontal (at the free boundary) sections of the medium. The characteristic features of the wave field are caused by the influence of its scattering on the local inhomogeneity. The features in the image of wave reliefs that arise at the intersection of the wave fronts of longitudinal waves - reflected from the free boundary and scattered on the local inhomogeneity - are studied. Informative signs, indicating the presence of the local heterogeneity and enable diagnostics of its parameters are established. The ways to improve the validity and reliability of algorithms for detection and classification of inhomogeneities and for evaluation of their difficulties using the listed types of waves are discussed. Based on the use of increasingly shorter probing pulses, the possibility of a detailed representation of reliefs and, consequently, the potentially achievable spatial resolution in probing the local subsurface inhomogeneities are demonstrated.
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MORALES, LUIZ, and LUÍS FERNANDES. "Propriedades Sísmicas Anisotrópicas Derivadas da Orientação Cristalográfica Preferencial de Muscovita-Quartzo Milonitos." Pesquisas em Geociências 34, no. 2 (2007): 03. http://dx.doi.org/10.22456/1807-9806.19466.
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Seismic wave propagation in organized matter usually results in azimuthal variations of longitudinal waves (Pwaves), as well as the effect of birefringence in transversal waves (S-waves), which results in two orthogonal shear waves with contrasting velocities. In this paper we present the results of the anisotropic seismic properties of five samples of muscovitequartz mylonites collected in different parts of a fold in the Saas Fee region, Western Internal Alps. The P-wave velocities in these rocks varies from 5.73 to 6.32 km/s, whereas the high-velocity shear wave (S1) varies from 3.82 to 4.22 km/s and the low velocity (S2) from 3.73 to 4.09 km/s. The anisotropy in these rocks is relatively high and reaches values from 9.5% for P-waves, and almost 11% for shear wave splitting. Both anisotropy and propagation directions seem to be related to from the strong preferred orientation of quartz and muscovite but also depend of muscovite modal content within the different specimens. Development of preferred orientation of minerals destroys and disperses the single crystal seismic properties, which causes a decrease of wave velocities and a dispersion of propagation directions, of both compressional and shear waves. Since the preferred orientation of quartz and muscovite can be directly related to the main macroscopic structures in these rocks (foliation, lineation, and pole of foliation) and the anisotropic seismic properties are related to the preferred orientation, it is possible to determine the propagation directions in terms of these structures. Due to the relatively high muscovite content, many of the maximum propagation velocities are parallel/subparallel to the foliation and some parallel to the lineation of the reference frame. On the other hand, directions of minimum propagation cannot be directly related to the foliation pole. The presence of folds in the mid-to lower crust can exert changes in the propagation directions due to the foliation variation around such structures, mainly in the P-waves.
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He, Cong, Guoyuan Xu, Zhigang Zhang, and Wei Li. "Seismic Response of Immersed Tunnel Subject to Oblique Incidence of SV Wave." Applied Sciences 12, no. 20 (2022): 10440. http://dx.doi.org/10.3390/app122010440.
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In view of the near-field seismic action, considering that oblique incidence of seismic waves is more realistic than vertical incidence, the seismic response of the Hong Kong–Zhuhai–Macao immersed tunnel subjected to an obliquely incident SV wave is investigated. Using the finite element method and time-domain wave method, the seismic input is transformed into an equivalent node load with a viscous–spring artificial boundary, and a three-dimensional simulation technology for SV waves of oblique incidence is presented. A half-space numerical example is given to demonstrate the accuracy of the proposed simulation technology. Taking the stress field formed by the self-weight stress and hydrostatic pressure as the initial state of the dynamic response analysis, the static–dynamic coupling numerical simulation of the seismic response of a soil-immersed tunnel system is realized. The results show that the amplification in the vertical and longitudinal response of the tunnel, due to the oblique incidence, reaches maximum when the incident angle is close to the critical angle. Furthermore, the horizontal response and incident angle show the inverse relation and tend to be stable. In addition, the oblique incidence also causes asymmetric shearing in symmetric parts of the tunnel. The root of the shear key easily produces tensile cracks, while the end angle of the shear key is prone to stress concentration and local damage. Thus, the impact of oblique incidence should be considered in the seismic design, and attention should be paid to the optimization of the end angle of the shear key and the configuration of anti-crack reinforcement at the root of shear key to meet the seismic requirements.
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Qian, Shenchun, Tao Cheng, Lei Mao, Xiaoxin Zhang, and Zhangliang Hu. "Influence of ground motion parameters on seismic response of a large-longitudinal-slope and small-radius curved girder bridge." PLOS ONE 19, no. 8 (2024): e0308456. http://dx.doi.org/10.1371/journal.pone.0308456.
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The mechanical performance of curved bridges under the action of an earthquake is complex. To obtain the influence of seismic parameters on the seismic response of curved girder bridges, this paper relies on a large slope small-radius curved steel box girder bridge (LSCGB) and selects seismic wave incidence angle, vertical component of ground motion, and site category as seismic parameters to carry out nonlinear time history analysis. Based on the analysis results of the case bridge, it is shown that the torsional vibration of the first 10 modes of LSCGB is significant, the modes are dispersed, and the contribution of high-order modes of vibration cannot be ignored. The most unfavorable seismic wave incidence angle is in the direction of 45°∼60° counterclockwise Angle from the central connection line of Pier No. 1 and Pier No. 4 of the bridge. The seismic response of the curved bridge components increases with the vertical seismic intensity, and the influence on displacement responses is more significant. The basic vibration period of curved girder bridges built on soft soil sites is extended by approximately 18.23%, and the seismic response of key components increases with the softening of the site soil. Therefore, when analyzing the seismic response of LSCGBs, the influence of vertical component of ground motion and site category should not be ignored.
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Yin, Can Bin, and Fang Yu. "Seismic Response Analysis of High Pier and Long Span Rigid Framed Bridge under Non Uniform Excitation." Applied Mechanics and Materials 193-194 (August 2012): 1315–19. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.1315.
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Taking the Longtan River Bridge as the engineering background , the seismic response analysis of high-pier and long-span continuous rigid-framed bridge considering travelling wave effect is simulated by means of the great mass method . Conclusions are drawn under asynchronous and synchronous excitation respectively , between which comparison indicates that the seismic responses for the main beams of continuous rigid-framed bridge are decreased at various degrees , such as the longitudinal horizontal displacement . The travelling wave effects on the piers are also related to the characteristics and locations of the bridge piers and so on .
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Chen, Bai Ben, Zhong Ren Feng, and Xiong Jiang Wang. "Analysis for Influence of Structural System on Nonlinear Seismic Response of Cable-Stayed Bridge." Advanced Materials Research 1065-1069 (December 2014): 856–59. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.856.
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For different structural system of cable-stayed bridge, the dynamic characteristics have obvious difference under seismic load. Dynamic time-history analysis of earthquake was applied, and the EI Centero seismic wave with modified peak acceleration was chose as the earthquake acceleration time-history input. As Jiangsu Siyang special-shaped single tower cable-stayed bridge for engineering background, considering geometric nonlinear of structure, the differences of dynamic characteristics of cable-stayed bridge structures were gained under two different situations. The single longitudinal seismic ground motion was chose under the first situation, while the longitudinal, lateral, and vertical seismic ground motion are introduced. For floating system, the displacements are the largest and the inner forces are the smallest. For rigid frame system, the displacements are the smallest and the inner forces are the largest. The others are not much difference. Comprehensively, semi-floating system has better performance under seismic load.
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Baev, Andrey V. "Solution of the inverse seismic problem in a layered elastic medium by means of the τ-p Radon transform". Journal of Inverse and Ill-posed Problems 26, № 5 (2018): 607–22. http://dx.doi.org/10.1515/jiip-2017-0083.
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Abstract We consider the inverse scattering problem in a layer-homogeneous elastic structure filling a half-plane. Scattering data is the seismic wave field registered on the boundary with a surface point source. We prove that velocities of longitudinal and transverse waves, and a density of the medium are recovered by a unique way. The algorithm of the inverse problem solution is based on the τ-p Radon transform. Also, we present some results of numerical modeling for waves propagation and solving of the inverse problem.
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Xu, Kai Yan, De Min Wei, and Can Liu. "Nonlinear Earthquake-Response Analysis of Wuhan Junshan Yangtze River under Uniform and Non-Uniform Excitations." Applied Mechanics and Materials 105-107 (September 2011): 1220–24. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1220.
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Wuhan Junshan Yangtze River Bridge is an important traffic hinge on Jing-Zhu freeway, it is very necessary to conduct the comprehensive and systemic investigation on the bridge aseismic. In this paper, the FEM model of it was established; the dynamic characteristic and nonlinear seismic responses under uniform and non-uniform excitations of it were systematic studied. The results show that: 1) the basic cycle of Wuhan Junshan Yangtze River Bridge is about 8.881s. Its first mode of vibration is longitudinal floating mode, which is favorable to the earthquake- response of structures. 2) Its former 40 rank frequency are located between 0.1~2Hz which is avail to the condition of traffic condition.3) the geometric nonlinearity has much influence on the response of this kind of bridge.4) the seismic responses are sensitive to the frequency spectra of the input earthquake wave. 5) The traveling wave excitations are unfavorable to the design of tower and the main girder when considering the three orthogonal seismic wave input. In order to get correct results, artificial seismic wave of the bridge address is necessary to the time-history analysis.
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Liu, Hong Biao, Xun Guo, and Yuan Yuan Yu. "Analysis of Seismic Resistance Capability of Masonry Structure." Advanced Materials Research 255-260 (May 2011): 2380–87. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2380.
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In order to analysis the seismic resistance mechanism of Staff apartment block of Beichuan telecommunication bureau (a six-storey-high masonry building in Beichuan County, meizoseismal area of Wenchuan earthquake), which just suffered from a moderate damage in the earthquake, ambient vibration survey and numerical simulation of structural earthquake response are carried out. Based on the ambient vibration survey, the natural frequencies of the building are acquired after Wenchuan earthquake. The first natural frequency in transverse and longitudinal is 3.45Hz and 3.65Hz, respectively, and the torsion frequency is 4.05Hz. The second natural frequency of the building in transverse is 7.55Hz, and that in longitudinal is not tested out. With Abaqus software, the earthquake response is computed out by inputting Wolong earthquake wave recorded in Wenchuan earthquake. The results of numerical simulation illustrate that the maximum acceleration amplification factor of the top floor in transverse and longitudinal is 5.28 and 6.68 severally. The maximum inter-story drift in transverse and longitudinal is 1/359 and 1/274 respectively, which are all exceed the limit of inter-story drift of masonry structure.
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Solovyev, Victor M., Alexander S. Salnikov, Viktor S. Seleznev, Tatyana V. Kashubina, and Natalya А. Galyova. "TO STUDY THE POSSIBILITIES OF USING THE SEISMOLOGICAL NETWORK OF THE ALTAI-SAYAN REGION FOR REGIME VIBRO-SEISMIC OBSERVATIONS." Interexpo GEO-Siberia 2, no. 2 (2021): 289–97. http://dx.doi.org/10.33764/2618-981x-2021-2-2-289-297.
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The results of deep seismic studies based on P - and S-wave data on the East-Stanov fragment of the reference 700-kilometer geophysical profile 8-DV are presented. Deep seismic sections of the upper crust (up to a depth of 20 km) with the distribution of the velocities of longitudinal and transverse waves are constructed. The P - wave velocities in the upper part of the section vary from 4-5 km / s within the Upper Zeya and Amur-Zeya depressions to 5.5-6.0 km/s within mountain ranges and plateaus; at depths of 10-20 km, lenses of high-velocity rocks up to 6.7-7.0 km/s are distinguished in the profile alignment. According to the S - waves in the upper part of the section, the velocity values are generally 3.0-3.2 km/s; reduced velocity values of 2.5-2.6 km / s are observed in the Upper Zey depression. At depths of 5-20 km within the section, according to the transverse wave data, a number of sections with reduced and increased velocity values are distinguished, respectively, up to 3.4-3.5 km/s and 3.75-3.8 km/s. The correlation of the selected anomalies according to the data of P-and S-waves is carried out.
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Bschorr, Oskar, and Hans-Joachim Raida. "Factorized One-Way Wave Equations." Acoustics 3, no. 4 (2021): 717–22. http://dx.doi.org/10.3390/acoustics3040045.
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The method used to factorize the longitudinal wave equation has been known for many decades. Using this knowledge, the classical 2nd-order partial differential Equation (PDE) established by Cauchy has been split into two 1st-order PDEs, in alignment with D’Alemberts’s theory, to create forward- and backward-traveling wave results. Therefore, the Cauchy equation has to be regarded as a two-way wave equation, whose inherent directional ambiguity leads to irregular phantom effects in the numerical finite element (FE) and finite difference (FD) calculations. For seismic applications, a huge number of methods have been developed to reduce these disturbances, but none of these attempts have prevailed to date. However, a priori factorization of the longitudinal wave equation for inhomogeneous media eliminates the above-mentioned ambiguity, and the resulting one-way equations provide the definition of the wave propagation direction by the geometric position of the transmitter and receiver.
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Rahkmankulova, Barna, Sayibdjan Mirzaev, Sharafidin Aynakulov, Rakhmatjon Khusainov, and Saparboy Khusainov. "Inertia force effect on longitudinal vibrations of underground pipelines." E3S Web of Conferences 264 (2021): 01007. http://dx.doi.org/10.1051/e3sconf/202126401007.
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The effect of the inertia term on the longitudinal displacements of an underground pipeline is shown for various cases of pipe fastening when a seismic wave propagates along its axis. The problem is solved by analytical and numerical methods. The pipe-soil interaction is assumed to be elastic (shear stress generated in soil is proportional to the relative displacement between the pipe and soil).
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Zhang, Xueming, Linlin Song, Hongjuan Chen, Shicai Chen, Zhinan Hu, and Yong Li. "Shaking Table Test Investigation on Seismic Performance of Joint Model of Immersed Tunnel." Shock and Vibration 2022 (March 20, 2022): 1–18. http://dx.doi.org/10.1155/2022/1095986.
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Critical for the seismic safety of immersed tunnels is the magnitude of deformation and force developing in the segment joints. To investigate the seismic performance of segment joint in immersed tunnel, this paper presents a series of shaking table arrays tests that were performed on a microconcrete tunnel model embedded in the soil. The tests take account of the uniform and wave passage effect in different apparent wave velocity of longitudinal seismic excitation. The result showed that the wave passage effect had a great impact on axial force, bending moment and deformation of joints. The comparison showed that structural response under nonuniform earthquake excitation is larger than that under uniform excitation. The simplified model was established in ABAQUS for numerical analysis. The soil around the tunnel was simplified as spring-damper, the tunnel was simplified as beam element, and the joint was simulated by nonlinear spring. The numerical simulation results were in good agreement with the experimental data. In addition, the model was analyzed by changing input apparent wave velocity, joint stiffness and joint number. The results showed that the deformation of joints was smaller and the deformation of flexible joints was greater under high apparent wave velocity.
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Shadmanova, G., K. Karimova, R. Khusainov, and S. Khusainov. "Longitudinal vibrations of underground pipelines of finite length with account for the node weight on the ends." Journal of Physics: Conference Series 2176, no. 1 (2022): 012077. http://dx.doi.org/10.1088/1742-6596/2176/1/012077.
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Abstract The paper presents an analysis of the dynamic response of an underground main pipe under the action of longitudinal wave, propagating in soil along the pipe. The outer surface of the pipeline is in contact with soil along the pipeline axis according to the elastic- viscous law, and the ends of the pipeline are connected to massive nodes by elastic elements. Using the Fourier method, an analytical solution to the problem of longitudinal vibration of an underground pipeline, pliantly fixed by nodes at its ends, is obtained. The problem of longitudinal vibration of an underground pipeline with visco-elastically fixed nodes at the ends is solved numerically. Longitudinal wave in soil is taken as a traveling sine wave. The paper presents a comparative analysis of the results for some values of seismic wavelengths, the ratio of the wave propagation velocity in soil and in the pipeline, the coefficients of elastic and viscous interaction. The viscosity coefficient of interaction at the "pipe-soil" system contact leads to attenuation of the wave front in the underground pipeline. For soils, the values of the viscous interaction coefficient of more than 100 kN⋅s/m2, may lead to complete attenuation of the bursts at the wave front in the pipeline.
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Huang, Wei-Hsiang, Zong-Ying Lin, and Tungyang Chen. "Energy attenuation of seismic metamaterials composed of a periodic array of coated elliptical cylinders." Journal of Mechanics 40 (2024): 491–504. http://dx.doi.org/10.1093/jom/ufae044.
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Abstract We present a numerical study on energy attenuation of seismic metamaterials consisting of a periodic array of coated elliptical cylinders. The aim is to perceive the effect of aspect ratio for different wave modes so that the metamaterials can interact with the incoming wave causing them to interfere with each other destructively, especially for low-frequency seismic waves with relatively wide bandgap. Previous studies mainly focused on the configuration of coated circular cylinders or spheres, in which the metamaterial is composed of a hard inclusion surrounded by a soft coating layer and dispersed within a hard matrix. Here we utilize numerical simulations based on finite element calculation to analyze the local fields within the unit cell. Effective mass density, mass moment of inertia and shear modulus are analyzed through a homogenization procedure to characterize the macroscopic behavior of the effective medium. The effective behavior will be dependent for different aspect ratios and for different types of wave motions. To verify the effectiveness of energy attenuation, a full-scale model is adopted. Specifically, to identify optimal energy attenuation configurations, we illustrate the attenuation effects of elliptical metamaterials under longitudinal and shear horizontal types of waves. The present study demonstrates that elliptical metamaterials will have more reflexibilities to tune with the aspect ratio of the elliptical geometry as well as the directionality of incidence waves. Based on our simulations, we show the ability of the designed configuration in tuning local resonance frequencies and bandwidths for real implementations and applications of seismic metamaterials.
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Musayev, Vyacheslav K. "Computer simulation of unsteady elastic stress waves in a console and a ten-storey building under fundamental influence in the form of a Heaviside function." Radioelectronics. Nanosystems. Information Technologies. 14, no. 2 (2022): 187–96. http://dx.doi.org/10.17725/rensit.2022.14.187.
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The aim of the work is to consider the problems of numerical simulation of seismic safety of a console and a ten-storey building with a base in the form of an elastic half-plane under non-stationary wave influences. Modeling of tasks of the transition period is an actual fundamental and applied scientific task. Methodology. To solve a two-dimensional plane dynamic problem of elasticity theory with initial and boundary conditions, the finite element method in displacements is used. Based on the finite element method in displacements, an algorithm and a set of programs have been developed for solving linear planar two-dimensional problems that allow solving problems with non-stationary wave effects on complex systems. The algorithmic language Fortran-90 was used in the development of the software package. Результаты. Results. The problem of the effect of a plane longitudinal wave in an elastic half-plane in the form of four trapezoids and in the form of two half-periods of a sinusoid is considered to assess the physical reliability and mathematical accuracy. A system of equations consisting of 8016008 unknowns is solved. The problem of the effect of a plane longitudinal elastic wave in the form of a Heaviside function on a console with a base (the ratio of width to height is one to ten) is considered. A system of equations consisting of 16016084 unknowns is solved. The problem of the effect of a plane longitudinal elastic wave in the form of a Heaviside function on a ten-storey building with a base in the form of a half-plane is considered. A system of equations consisting of 16202276 unknowns is solved. Contour stresses and components of the stress tensor are obtained in the characteristic areas of the problem under study. Based on the conducted research, the following conclusions can be drawn. Elastic contour stress on the sides of the console and a ten-story building are almost a mirror image of each other, that is, antisymmetric. The console and supporting structures of the building work like a beam during seismic action, that is, if there are tensile stresses on one side, then compressive stresses on the other. Bending waves mainly prevail on the contours of the console and supporting structures of the building under seismic influence.
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Khusainov, Rakhmatjon, Javlon Yarashov, and Saparboy Khusainov. "Application of finite difference method for solving problem of seismic resistance of underground pipelines." E3S Web of Conferences 401 (2023): 05046. http://dx.doi.org/10.1051/e3sconf/202340105046.
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The paper analyzes the dynamic response of an underground main pipe under the action of a longitudinal wave propagating in soil along the pipe. The article assumes that the elastic pipe is of a finite length, and a linear viscoelastic model of the “pipe-soil” system interaction is considered. The problem is solved numerically using the explicit scheme of the finite difference method. A longitudinal wave in the soil is taken as a traveling sine wave. The article presents a comparative analysis of the results for certain values of elastic and viscous interaction coefficients, propagation velocity, and pulse duration. Under elastic interaction of the “pipe-soil” system, the reflection of the wave propagating in the underground pipeline at the boundaries of the pipeline coincides with the propagating wave in soil, leading to an increase in the maximum deformation of the underground pipeline, the value of which can double. The viscosity coefficient of interaction at the “pipe-soil” system contact leads to attenuation of the wavefront in the underground pipeline. For soils with values of viscous interaction coefficient of more than 100 kN·s/m2, this may lead to complete attenuation of the bursts at the wavefront in the pipeline. The choice of the step ratio in coordinate and time equal to the wave propagation velocity in the pipeline allows for obtaining results that coincide with the exact solution.
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Xu, Kai Yan. "Earthquake-Response Analysis of Long-Span Cable-Stayed Bridge under Uniform and Non-Uniform Excitations." Applied Mechanics and Materials 574 (July 2014): 36–40. http://dx.doi.org/10.4028/www.scientific.net/amm.574.36.
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Earthquake is a kind of natural disaster which is difficult to predict and the damage degree is very great, occurrence of the strong motion often leads to the tremendous life and property loss. Bridge is very important lifeline engineering and it is very necessary to conduct the comprehensive and systemic investigation on the bridge aseismic. In this paper, the FEM model of a long-span cable-bridge was established; the dynamic characteristic and nonlinear seismic responses under uniform and non-uniform excitations of it were systematic studied. The results show that: 1) the basic cycle of it is about 8.881s. Its first mode of vibration is longitudinal floating mode, which is favorable to the earthquake-response of structures. 2) Its former 40 rank frequency are located between 0.1~2Hz which is avail to the condition of traffic condition.3) the geometric nonlinearity has much influence on the response of this kind of bridge.4) the seismic responses are sensitive to the frequency spectra of the input earthquake wave. 5) The traveling wave excitations are unfavorable to the design of tower and the main girder when considering the three orthogonal seismic wave input. In order to get correct results, artificial seismic wave of the bridge address is necessary to the time-history analysis.
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Kanareykin, B. A., A. S. Salnikov, D. P. Napreev, E. V. Mosyagin, and E. Yu Goshko. "POSSIBILITIES OF SEISMIC EXPLORATION IN STUDYING THE FOLDED STRUCTURE OF ANTHRACITES (GORLOVSKY BASIN)." Geology and mineral resources of Siberia, no. 2 (2023): 33–40. http://dx.doi.org/10.20403/2078-0575-2023-2-33-40.
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The paper presents the results of experimental and methodological seismic and electrical exploration along the profile crossing the productive formation of coal seams in the Gorlovsky anthracite basin (Doroginskoye deposit, Shadrinsky block). The obtained CDP time cross sections indicate the possibility of displaying some elements of the folded structure of thick anthracite seams in the wave field at depths up to 300-350 m. Seismic tomography with the use of first arrivals of longitudinal waves allows scientists to reconstruct in detail the velocity structure of the near-surface part of the section to depths of 120-150 m and to identify low-velocity local objects corresponding to the upper edges of the thickest coal members in the upper part of Permian deposits.
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Al-kafaji, Ammar. "Using Seismic Cross-Hole Method to Evaluate Soil Improvement for Outside Wall in Al-Abbas Holy Shrine in Holy Karbala, Iraq." Iraqi Geological Journal 55, no. 2D (2022): 73–82. http://dx.doi.org/10.46717/igj.55.2d.7ms-2022-10-23.
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The aim of this study is to use the seismic cross-hole survey in evaluating the injection work to fill the cavities spread in the soil underneath the old foundation of the outer wall of the Al-Abbas holy shrine. A seismic cross-hole survey was conducted for eight profiles, four of these are applied before grouting and four profiles are done after grouting at Al-Imam Musa Al-Kadhum and Al-Imam Sahib Al-Zaman gates. Using the longitudinal and shear wave velocities for different depths ranging from 1 to 15 m. The results of the survey indicate that the soil injection process was successful and effective in filling the cavities. The results of cross- hole survey after the grouting show the percent of variation is 0.7-77 percent for seismic shear wave velocity more than before grouting to variant depths.