http://jeg.khu.ac.ir Journal of Engineering Geology - Journal articles for year 2014, Volume 8, Number 1 Yektaweb Collection - https://yektaweb.com en 2014/7/10 http://ndea10.khu.ac.ir/jeg/browse.php?a_id=1616&sid=1&slc_lang=en http://ndea10.khu.ac.ir/jeg/browse.php?a_id=1615&sid=1&slc_lang=en http://ndea10.khu.ac.ir/jeg/browse.php?a_id=403&sid=1&slc_lang=en In the recent years there was a great improvement in the development of underground structures. Due to the increase in the costs of constructions and the importance of the safety in transportation, attention has been focused on the hazards of earthquakes. In this paper, the effect of earthquakes and the importance of seismic analysis are described. The analysis method is presented briefly, and then the simplified analysis of Hashash et al. (2001) is used. Two metro station structures under two different seismic hazardlevels were analyzed. Pushover analysis method is also used which is a simple and static non-linear method in seismic analysis and design of structures.  In this non-linear analysis, the target displacement is computed by the simplified frame analysis model. The finding of this study showed that the structure behavior was remained elastically to a large extent of displacement using this method. Hence, the design of the structures based on the performance level or reduction of the moment extracted from the Hashash et al. (2001) method is recommended. P Homami http://ndea10.khu.ac.ir/jeg/browse.php?a_id=417&sid=1&slc_lang=en Comprehensive laboratory tests were performed to assess fatigue behavior of Alvand monzogranite rock subjected to uniaxial cyclic loading. A series of static loading tests was done to obtain the required data for the fatigue tests. Three maximum load levels (85, 90, 95% uniaxial compressive strength (&sigmac)) at amplitudes 70% were used with 1Hz cyclic loading frequency. The results indicated that maximum stress level significantly influenced fatigue behavior of this rock. It was found that fatigue life decreases in a power function with increasing maximum stress level. Accumulative fatigue damage process shows three stages of behavior including crack initiation phase, uniform velocity phase and acceleration phase. Fatigue damage process were analyzed according to axial and lateral maximum and minimum strain, tangent and second modulus, toughness and hysteresis energy in both loading and unloading conditions. Among these parameters, lateral strain, axial strain and second modulus show the best three-stage fatigue damage behavior. Also, it should be noted that most of the cracks generated in parallel to loading direction and lateral strain are affected by more than axial strain.   Gh Khanlari