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Relationship between critical seismic acceleration coefficient and static factor of safety of 3D slopes
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作者 SHI He-yang CHEN Guang-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第5期1546-1554,共9页
Many analytical methods have been adopted to estimate the slope stability by providing various stability numbers,e.g.static safety of factor(static FoS)or the critical seismic acceleration coefficient,while little att... Many analytical methods have been adopted to estimate the slope stability by providing various stability numbers,e.g.static safety of factor(static FoS)or the critical seismic acceleration coefficient,while little attention has been given to the relationship between the slope stability numbers and the critical seismic acceleration coefficient.This study aims to investigate the relationship between the static FoS and the critical seismic acceleration coefficient of soil slopes in the framework of the upper-bound limit analysis.Based on the 3D rotational failure mechanism,the critical seismic acceleration coefficient using the pseudo-static method and the static FoS using the strength reduction technique are first determined.Then,the relationship between the static FoS and the critical seismic acceleration coefficient is presented under considering the slope angleβ,the frictional angleφ,and the dimensionless coefficients B/H and c/γH.Finally,a fitting formula between the static FoS and the critical seismic acceleration coefficient is proposed and validated by analytical and numerical results. 展开更多
关键词 static safety of factor critical seismic acceleration coefficient upper-bound limit analysis 3D rotational failure mechanism
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Machine learning-enhanced Monte Carlo and subset simulations for advanced risk assessment in transportation infrastructure
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作者 Furquan AHMAD Pijush SAMUI S.S.MISHRA 《Journal of Mountain Science》 SCIE CSCD 2024年第2期690-717,共28页
The maintenance of safety and dependability in rail and road embankments is of utmost importance in order to facilitate the smooth operation of transportation networks.This study introduces a comprehensive methodology... The maintenance of safety and dependability in rail and road embankments is of utmost importance in order to facilitate the smooth operation of transportation networks.This study introduces a comprehensive methodology for soil slope stability evaluation,employing Monte Carlo Simulation(MCS)and Subset Simulation(SS)with the"UPSS 3.0 Add-in"in MS-Excel.Focused on an 11.693-meter embankment with a soil slope(inclination ratio of 2H:1V),the investigation considers earthquake coefficients(kh)and pore water pressure ratios(ru)following Indian zoning requirements.The chance of slope failure showed a considerable increase as the Coefficient of Variation(COV),seismic coefficients(kh),and pore water pressure ratios(ru)experienced an escalation.The SS approach showed exceptional efficacy in calculating odds of failure that are notably low.Within computational modeling,the study optimized the worst-case scenario using ANFIS-GA,ANFIS-GWO,ANFIS-PSO,and ANFIS-BBO models.The ANFIS-PSO model exhibits exceptional accuracy(training R2=0.9011,RMSE=0.0549;testing R2=0.8968,RMSE=0.0615),emerging as the most promising.This study highlights the significance of conducting thorough risk assessments and offers practical insights into evaluating and improving the stability of soil slopes in transportation infrastructure.These findings contribute to the enhancement of safety and reliability in real-world situations. 展开更多
关键词 Monte Carlo Simulation Subset Simulation Machine Learning seismic coefficient
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Analytical expressions for determining the stability of cohesionless soil slope under generalized seismic conditions
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作者 SAHOO Pragyan Pradatta SHUKLA Sanjay Kumar MOHYEDDIN Alireza 《Journal of Mountain Science》 SCIE CSCD 2018年第7期1559-1571,共13页
In recent major earthquakes, the researchers have found the need for consideration of vertical seismic acceleration for the stability analysis of the man-made and natural slopes. However, in most past studies, the per... In recent major earthquakes, the researchers have found the need for consideration of vertical seismic acceleration for the stability analysis of the man-made and natural slopes. However, in most past studies, the performance of slopes has been assessed by accounting only the horizontal seismic component of the ground motion, without giving due weightage to the effect of vertical component. In the present study, analytical expressions are derived to determine the factor of safety, yield seismic coefficient and consequently the seismic displacement of cohesionless soil slope under combined horizontal and vertical components of the ground motion. The derivation uses the Newmark's sliding block approach, in which the soil slope with a planar failure surface within the framework of conventional pseudo-static analysis is assumed to follow the Mohr-Coulomb failure criterion. The effects of vertical seismic coefficient on the stability of cohesionless slope have been studied through a set of graphical presentations for a specific range of soil parameters. It is observed that overlooking the effect of the vertical component of the ground motion on factor of safety and the displacement while designing the slope may be detrimental, resulting in the slope failure. The general expressions presented in this paper may be highly useful in the field of earthquake geotechnical engineering practice for designing the cohesionless soil slopes under combined horizontal and vertical seismic loads. 展开更多
关键词 Factor of safety Horizontal and vertical seismic coefficients Soil slopes Yield acceleration Sliding block displacement seismic slope stability
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Dynamic behavior of single-layer latticed cylindrical shells subjected to seismic loading 被引量:4
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作者 沈世钊 邢佶慧 范峰 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2003年第2期269-279,共11页
The single-layer latticed cylindrical shell is one of the most widely adopted space-fl'amed structures.In this paper,free vibration properties and dynamic response to horizontal and vertical seismic waves of singl... The single-layer latticed cylindrical shell is one of the most widely adopted space-fl'amed structures.In this paper,free vibration properties and dynamic response to horizontal and vertical seismic waves of single-layer latticed cylindrical shells are analyzed by the finite element method using ANSYS software.In the numerical study,where hundreds of cases were analyzed,the parameters considered included rise-span ratio,length-span ratio,surface load and member section size.Moreover,to better define the actual behavior of single-layer latticed shells,the study is focused on the dynamic stress response to both axial forces and bending moments.Based on the numerical results,the effects of the parameters considered on the stresses are discussed and a modified seismic force coefficient method is suggested.In addition,some advice based on these research results is presented to help in the future design of such structures. 展开更多
关键词 single-layer latticed cylindrical shell dynamic behaviors seismic force coefficient method rise-span ratio length-span ratio surface load intensity member section size
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Seismic force modification factor for ductile structures 被引量:1
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作者 童根树 黄金桥 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第8期813-825,共13页
The earthquake forces used in design codes of buildings should be theoretically determinable. This work examines the seismic force modification factor R based on elastic-plastic time-history earthquake analysis of SDO... The earthquake forces used in design codes of buildings should be theoretically determinable. This work examines the seismic force modification factor R based on elastic-plastic time-history earthquake analysis of SDOF systems, wherein the hys-teresis models are elastic-perfectly-plastic (EPP), elastic-linearly-hardening (ELH), shear-slipped and bilinear-elastic. The latter two models are analysed for separating the effect of the ductility and the energy-dissipating capacity. Three-hundred eighty-eight earthquake records from different site conditions are used in analysis. The ductility is taken to be 2, 3, 4, 5 and 6, with the damping ratio being 0.02, 0.035 and 0.05 respectively. The post-yield stiffness ratios 0.0, 0.1 and 0.2 are used in the analysis. The R spectra are standardized by the characteristic period of the earthquake records, which leads to a much smaller scatter in averaged numerical results. It was found that the most important factor determining R is the ductility. R increases more than linearly with ductility. The energy-dissipating capacity, damping and the post-yield stiffness are the less important factors. The energy dissipating capacity is important only for structures with short period and moderate period (0.3≤T/Tg<5.0). For EPP and ELH models, R for 0.05 damping is 10% to 15% smaller than for 0.02 damping. For EPP and ELH models, greater post-yield stiffness leads to greater R, but the influence of post-yield stiffness is obvious only when the post-yield stiffness is less than 10% of the initial stiffness. By means of statistical regression analysis the relation of the seismic force modification factor R with the natural period of the system and ductility for EPP and ELH models were established for each site and soil condition. 展开更多
关键词 Aseismic design seismic force modification coefficient DUCTILITY Energy-dissipating capacity
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Experimental study on the influence of seismic subsidence of loess under bidirectional loading modes 被引量:2
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作者 Gaofeng Che Ping Wang +3 位作者 Qian Wang Xiaowu Pu Jinlian Ma Shaofeng Chai 《Earthquake Research Advances》 CSCD 2021年第4期48-52,共5页
Water content,dry density,void ratio,depth of soil layer,and seismic loading may all exert influence on the seismic subsidence of loess.Many scholars have carried out seismic subsidence tests of loess to simulate the ... Water content,dry density,void ratio,depth of soil layer,and seismic loading may all exert influence on the seismic subsidence of loess.Many scholars have carried out seismic subsidence tests of loess to simulate the stress on soil using unidirectional(axial)vibration instead of bidirectional vibration.We conduct seismic subsidence tests of loess using two different dynamic stress loading methods,unidirectional and bidirectional dynamic stress.In addition,the effects of different dynamic stress loading modes on the development of seismic subsidence of loess are compared for a case-study in northwestern China.The results show that(1)the increasing ratio of radial stress to axial stress has exerted significant influence on the seismic subsidence coefficient of loess under the loading mode of bidirectional dynamic stress(2)there is a critical ratio of radial stress to axial stress for seismic subsidence of loess,ranging from 0.6 to 0.8;when the ratio of radial load to axial load is greater than the critical value,the effect of bidirectional load on the development of seismic subsidence is more remarkable(3)when the ratio of radial load to axial load is smaller,the seismic subsidence of loess calculated by the existing unidirectional stress loading method is safe for engineering projects.However,if the value exceeds the safety ratio range it is dangerous to conduct safety evaluations using the seismic loess subsidence.The prediction value of seismic subsidence at engineering sites directly affects the later foundation treatment and the safety of the overlying structures.The seismic subsidence calculation and evaluation method in this study may provide a scientific basis for safety evaluations of loess sites in northwestern China. 展开更多
关键词 LOESS Radial stress Axial stress coefficient of seismic subsidence
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Distribution of acceleration and empirical formula for calculating maximum acceleration of rockfill dams
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作者 周晖 李俊杰 康飞 《Journal of Central South University》 SCIE EI CAS 2010年第3期642-647,共6页
To find the distribution patterns of dynamic amplification coefficients for dams subjected to earthquake, 3D seismic responses of concrete-faced rockfill dams with different heights and different shapes of river valle... To find the distribution patterns of dynamic amplification coefficients for dams subjected to earthquake, 3D seismic responses of concrete-faced rockfill dams with different heights and different shapes of river valley were analyzed by using the equivalent-linear model. Statistical analysis was also made to the seismic coefficient, and an empirical formula for calculating the maximum acceleration was provided. The results indicate that under the condition of the same dam height and the same base acceleration excitations, with the increase of the river valley width, the position of the maximum acceleration on the axis of the top of the dam moves from the center to the riversides symmetrically. For the narrow valleys, the maximum acceleration occurs in the middle of the axis at the top of the dam; for wide valleys the maximum acceleration appears near the riversides. The result negates the application of 2D dynamical computation for wide valleys, and shows that for the seismic response of high concrete-faced rockfill dams, the seismic coefficient along the axis should be given, except for that along the dam height. Seismic stability analysis of rockfill dams using pseudo-static method can be modified according to the formula. 展开更多
关键词 concrete-faced rockfill dam 3D dynamical response analysis equivalent-linear method ACCELERATION seismic coefficient statistical analysis
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Ethical Principles Underlying the Assessment of Indirect Losses Due to Earthquakes
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作者 Jaime García-Pérez Eric García-López 《Open Journal of Civil Engineering》 2021年第2期179-199,共21页
The reliability optimization process in earthquake engineering requires that the expected present value of the total cos<span style="color:black;font-family:Verdana;">t is mini</span><span sty... The reliability optimization process in earthquake engineering requires that the expected present value of the total cos<span style="color:black;font-family:Verdana;">t is mini</span><span style="font-family:Verdana;">mized, including the initial cost as well as the damage costs caused by earthquakes, which include indirect costs. One of these costs is concerned with how much society is willing to invest for preserving human life. Ethical principles, on which to base the assessment of this cost, are presented and discussed in this work. Individual and social values are analyzed. Finally, an optimal seismic design coefficient with the results obtained is calculated for a site with low seismicity.</span> 展开更多
关键词 Reliabilities UTILITY Indirect Losses DECISION-MAKING seismic coefficients
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Applying accurate gradients of seismic wave reflection coefficients (SWRC) to the inversion of seismic wave velocities 被引量:3
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作者 LIU FuPing MENG XianJun +2 位作者 XIAO JiaQi WANG YuMei SHEN GuoQiang 《Science China Earth Sciences》 SCIE EI CAS 2012年第12期1953-1960,共8页
Through solving the Zoeppritz's partial derivative equations, we have obtained accurate partial derivatives of reflected coefficients of seismic wave with respect to Pand S-wave velocities.With those partial deriv... Through solving the Zoeppritz's partial derivative equations, we have obtained accurate partial derivatives of reflected coefficients of seismic wave with respect to Pand S-wave velocities.With those partial derivatives, a multi-angle inversion is developed for seismic wave velocities.Numerical examples of different formation models show that if the number of iterations goes over 10, the relative error of inversion results is less than 1%, whether or not there is interference among the reflection waves.When we only have the reflected seismograms of P-wave, and only invert for velocities of P-wave, the multi-angle inversion is able to obtain a high computation precision.When we have the reflected seismograms of both P-wave and VS-wave, and simultaneously invert for the velocities of P-wave and VS-wave, the computation precisions of VS-wave velocities improves gradually with the increase of the number of angles, but the computation precision of P-wave velocities becomes worse.No matter whether the reflected seismic waves from the different reflection interface are coherent or non-coherent, this method is able to achieve a higher computation precision.Because it is based on the accurate solution of the gradient of SWRCs without any additional restriction, the multi-angle inversion method can be applied to seismic inversion of total angles.By removing the difficulties caused by simplified Zoeppritz formulas that the conventional AVO technology struggles with, the multiangle inversion method extended the application range of AVO technology and improved the computation precision and speed of inversion of seismic wave velocities. 展开更多
关键词 Zoeppritz’s partial derivative equations inversion of seismic wave velocity grads of seismic wave reflection coefficients (SWRCs) multi-angle inversion
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Estimation of active earth pressure based on pseudo-dynamic approach and discretization technique 被引量:2
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作者 LUO Wen-jun GONG Chen-jie +1 位作者 WANG Huan-yu YANG Xiao-li 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第9期2890-2904,共15页
A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduce... A method combining the pseudo-dynamic approach and discretization technique is carried out for computing the active earth pressure.Instead of using a presupposed failure mechanism,discretization technique is introduced to generate the potential failure surface,which is applicable to the case that soil strength parameters have spatial variability.For the purpose of analyzing the effect of earthquake,pseudo-dynamic approach is adopted to introduce the seismic forces,which can take into account the dynamic properties of seismic acceleration.A new type of micro-element is used to calculate the rate of work of external forces and the rate of internal energy dissipation.The analytical expression of seismic active earth pressure coefficient is deduced in the light of upper bound theorem and the corresponding upper bound solutions are obtained through numerical optimization.The method is validated by comparing the results of this paper with those reported in literatures.The parametric analysis is finally presented to further expound the effect of diverse parameters on active earth pressure under non-uniform soil. 展开更多
关键词 pseudo-dynamic approach discretization technique upper-bound analysis INHOMOGENEITY seismic active earth pressure coefficient
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