بررسي ارتباط عدد نفوذ استاندارد و احتمال وقوع روان‌گرايي با استفاده از روش اعتمادپذيري در خاك‌هاي ماسه‌يي‌

STANDARD PENETRATION NUMBER CORRELATION WITH PROBABILITY OF LIQUEFACTION OCCURANCE USING RELIABILITY METHOD IN SANDY SOIL

Methods of evaluat ing the liqu efaction potential in sandy soil is gener ally based on determ inistic a nalysis. In deterministic analysis , paramet ers are considered precise , without variance and error. As well as using these methods, one is unable to make a connection between th e probability of liquefac tion occurance and t he safety factor. This problem can be answered by reliability analysis. In this pap er , reliability analysis, based on the popular Seedʹ85 method of liquefaction evaluation, using standard penetration test results, is offered. Since this method requires quantifying uncertainty values in calculation , one can use th e statistical moment of und eterministic paramet ers , such as the mean, variance and probability density function (PDF), for determination of the most probable uncertainties . Then , using the advanced , first-order second-moment (AFOSM) technique, the reliability index is calcula ted an d the rela tion probability of liqu efaction occurance, reliability index and safety fact or are dedu ced . For ana lysis of the data, st atistical regression is used to establish a relationship between eart hquake characte ristics , resistance and the potential of liquefaction occur ance of th e soil, based on th e prop osed method and 180 field record s in the Bab olsar region. A comparison between the prop osed method a nd the previou s meth od shows good agreement