وقوع تغيير شكل هاي بزرگ در توده خاكي حاصل از عملكرد گسل ها

چكيده انگليسي :

Large deformation induced in soil masses due to fault rupture Zeynab Khorami Ejlali z khorami@cv iut ac ir June 07 2015 Department of Civil Engineering Isfahan University of Technology 84156 83111 IranDegree M Sc Language FarsiDr M Vafaeian mahmood@cc iut ac irDr A Eslami Haghighat eslami@cc iut ac irAbstractIn a seismic event the rupture of an earthquake fault can generate two types of ground displacement containingpermanent quasistatic offsets on the fault itself and transient dynamic oscillations away from the fault The firsttype of displacement affects the ground surface only in cases that the fault rupture extends all the way to thesurface By contrast the latter displacement is the result of seismic waves originating and propagates over largedistances in the earth and are thus of prime significance for the safety of civil engineering structures Thus extensive studies have been devoted to them Among the structures the embankment dams and their safeties areof great importance and there are still dams constructed over active faults Since dam failure may result incatastrophic events it is prudent to gain an understanding of the phenomenon of base fault displacement andfault rupture propagation through the embankment dam The results of this understanding of the phenomenon offault rupture propagation through soil may lead to designing of buildings and critical facilities in the vicinity ofactive faults This research is aimed to develop an understanding of the phenomenon of reverse dip slip fault rupturepropagation through soil Then as a practical approach fault rupture propagation through embankment dams isstudied A finite element base software ABAQUS is employed as a tool for the numerical modeling of faultrupture propagation through soil using nonlinear elastic plastic constitutive behavior At the first step theimportant issues related to the factors affecting the fault rupture propagation through a horizontal soil layer areevaluated in numerical modeling The results showed that the increase of friction angle and elastic modulus ofthe materials leads to decreasing of the fault rupture path Simultaneous study of the influence of soil type interms of density and fault dip angle demonstrated that fault rupture path tends to bend more in dense soilscomprising loose ones At the second step fault rupture propagation through homogenous and zonedembankments is discussed The results are presented in from two points of view rupture path throughembankment dams and surface displacement Three different zones within the embankment were recognized interms of fault rupture paths so that the influence of each factor like the fault properties and material propertiescan be different in these zones Moreover the effect of the dam height was studied in this research as one of themost important factors It was shown that changing the height of the dam can completely lead to differentrupture paths When the embankment dam has the lower height a localized rupture path is formed in line withthe fault angle As the height of the dam is increased the rupture path is dispersed so that one localized rupturepath is not recognized anymore Finally the effect of presence of a horizontal alluvium under the dam base onrupture propagation and the surface displacement is evaluated The important result was that the presence ofalluvium foundation may lead to diversion of fault rupture path decreasing of the surface displacement gradientand dispersion of rupture path in some regions with high effective stress levels It is hoped that this research bethe initial step of comprehensive surveys about the phenomenon of fault rupture propagation and also presentingexecutive measures to reduce the destructive effects of that KeywordsFault rupture Numerical modelling Fininte element analyse Embankment dam ABAQUS

خرمي اجلالي، زينب

وقوع تغيير شكل هاي بزرگ در توده خاكي حاصل از عملكرد گسل ها

گسلش , مدلسازي عددي , تحليل المان محدود , آباكوس , سدخاكي