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Propagation of seismic waves through soil layers would drastically change the frequency content and amplitude-based features of ground motions at the surface. These alterations are known as seismic site effects. Computation of site effects of high-populated areas such as large cities is of great importance (e.g., it is used in development of seismic microzonation of a region). Shiraz is one of the most populous cities of Iran and is located in a high seismic hazardous region. A representative clay site in this city is selected to assess local site effects. The time series and random vibration theory procedure in the frequency domain are implemented to analyze the aforementioned site. Furthermore, the nonlinear dynamic soil behavior is simulated by the equivalent linear method and the nonlinear method via DEEPSOIL program. Three types of soil column uncertainties such as shear wave velocity, modulus reduction, and damping ratio of soil layers as well as depth of underlying rock half-space (D bed) are considered herein. The mean amplification and standard deviation of natural logarithm of amplification factors are computed for a variety of analysis types. The results of the current study show that the computed mean and standard deviation of amplification factor in ln units by considering only V S uncertainty are in good agreement with the corresponding ones by considering V S and modulus reduction and damping ratio variabilities simultaneously for the studied site. Furthermore, it seems that the effect of bedrock depth in definition of spectral shapes of the Iranian seismic building code should be taken into account. 相似文献
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Alireza Eskandarinejad Hamid Zafarani Mojtaba Jahanandish 《Journal of Seismology》2018,22(6):1629-1643
Estimation of ground-motion amplitudes of different hazard levels is of paramount importance in planning of urban development of any metropolis. Such estimation can be computed through a probabilistic seismic hazard analysis (PSHA). This paper concentrates on the PSHA of an area located in Shiraz city, southern Iran. The area includes whole of Shiraz city (i.e., one of the largest and most populous cities of Iran) and its outskirts. Conventional and Monte Carlo simulation-based approaches are utilized to perform the PSHA of the studied area. Two areal seismic source models are delineated, and thence seismicity parameters of all zones associated with their corresponding uncertainties are computed. Uncertainties in ground-motion prediction are accounted for via three ground-motion prediction equations (GMPEs) within the logic tree framework. These GMPEs are applied to estimate bedrock ground shaking (Vs30?=?760 m/s) for several return periods (i.e., 75, 475, 975, and 2475 years). In general, the results of the two abovementioned PSHA approaches show relatively similar results. However, the Monte Carlo simulation-based approach overpredicts bedrock spectral accelerations at periods of 0.4–2.5 s compared to the conventional PSHA approach for return periods of 475, 975, and 2475 years. 相似文献
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Zafarani Hamid Jafarian Yaser Eskandarinejad Alireza Lashgari Ali Soghrat Mohammad Reza Sharafi Hassan Afraz-e Haji-Saraei Masoud 《Natural Hazards》2020,103(2):1783-1805
Natural Hazards - A strong earthquake occurred on November 12, 2017, in Sarpol-e Zahab city, western Iran, with the moment magnitude ( $$M_{{\text{w}}}$$ ) of 7.3 and a focal depth of... 相似文献
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Seismic Passive Earth Thrust on Retaining Walls with Cohesive Backfills Using Pseudo-Dynamic Approach 总被引：2，自引：1，他引：1
A. H. Shafiee A. Eskandarinejad M. Jahanandish 《Geotechnical and Geological Engineering》2010,28(4):525-531
In this paper, the pseudo-dynamic approach is used to estimate seismic passive earth thrust on retaining walls with cohesive-frictional
backfills. The time-dependent pseudo-dynamic approach considers the influence of dynamic parameters such as the velocity of
primary and shear waves, the period of lateral shaking, and the phase and amplitude variations of horizontal and vertical
earthquake accelerations with depth. The failure plane behind the wall is assumed to be planar. The analysis is based on the
equilibrium of forces which act within the failure wedge. The obtained results show that the backfill cohesion increases both
the seismic passive earth thrust and the failure plane inclination angle with the horizontal plane. It is also observed that
both horizontal and vertical seismic accelerations have decreasing effect on seismic passive earth thrust as well as failure
plane inclination angle. The results of present pseudo-dynamic analysis propose a lower solution for seismic passive earth
thrust compared to earlier pseudo-static solution available in the literature. 相似文献
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