Static and dynamic analysis on slope stability using a DFN-DEM approach on the right abutment of the Karun 4 dam     

Kefayati  Sadegh  Baghbanan  Alireza  Torkan  Masoud  Hashemolhosseini  Hamid  Dehnavi  Roohollah Narimani 《地震工程与工程振动(英文版)》2020,19(4):937-951

Uncertainty in input fracture geometric parameters during analysis of the stability of jointed rock slopes is inevitable and therefore the stochastic discrete fracture network (DFN) — distinct element method (DEM) is an efficient modeling tool. In this research, potentially unstable conditions are detected in the right abutment of the Karun 4 dam and downstream of the dam body as a case study. Two extreme states with small and relatively large block sizes are selected and a series of numerical DEM models are generated using a number of validated DFN models. Stability of the rock slope is assessed in both static and dynamic loading states. Based on the design basis earthquake (DBE) and maximum credible earthquake (MCE) expected in the dam site, histories of seismic waves are applied to analyze the stability of the slope in dynamic earthquake conditions. The results indicate that a MCE is likely to trigger sliding of rock blocks on the rock slope major joint. Furthermore, the dynamic analysis also shows a local block failure by the DBE, which can consequently lead to slope instability over the long term. According to the seismic behavior of the two models, larger blocks are prone to greater instability and are less safe against earthquakes.

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The spatial analysis of thunderstorm hazard in Iran     

Yousef Ghavidel  Parasto Baghbanan  Manuchehr Farajzadeh 《Arabian Journal of Geosciences》2017,10(5):123

In this study, monthly, quarterly, and annual frequency data of thunderstorm days of 25 long-term synoptic weather stations during the period from 1960 to 2010 were analyzed applying Ward’s Hierarchical Cluster Analysis (WHCA) Method and Kriging Geostatistical Method (KGM). The results of temporal analysis of Thunderstorm Days (TD) in Iran showed that in terms of frequency, seasonal occurrence of this phenomenon is mostly in transitional seasons of spring and autumn. The results of WHCA to find homogeneous places in terms of synchronization and timing of TD reflects the fact that there are five clusters with similar memberships, including the North West, West, the southern part, northern, central, and northeastern parts, eastern regions, and center of Iran, and in this classification, the frequency of occurrence of TD reduces in the same order the regions are mentioned. In contrast, the lowest frequency of TD is in summer and winter seasons. In this study, it was found that among various deterministic and geostatistical methods, KGM is the most suitable one for thunderstorms hazard zonation and for classifying the different regions based on thunderstorm occurrence; WHCA is more suitable than other methods. The results of spatial analysis of thunderstorms point to the fact that the core of the mentioned thunderstorms is mostly in mountainous areas, particularly, highlands of North West and West of Iran. With regard to place, in the West part of the country, especially North West (Tabriz, Oroomieh, and Zanjan stations) and West, thunderstorms have higher frequencies, while the South East, South, Central, and eastern regions are less affected by the thunderstorm hazard.  相似文献   

Effect of seismic waves on the hydro-mechanical properties of fractured rock masses     

Meysam Lak  Alireza Baghbanan  Hamid Hashemolhoseini 《地震工程与工程振动(英文版)》2017,16(3):525-536

The transmission of seismic waves in a particular region may influence the hydraulic properties of a rock mass, including permeability, which is one of the most important. To determine the effect of a seismic wave on the hydraulic behavior of a fractured rock mass, systematic numerical modeling was conducted. A number of discrete fracture network(DFN) models with a size of 20 m × 20 m were used as geometrical bases, and a discrete element method(DEM) was employed as a numerical simulation tool. Three different boundary conditions without(Type Ⅰ) and with static(Type Ⅱ) and dynamic(Type Ⅲ) loading were performed on the models, and then their permeability was calculated. The results showed that permeability in Type Ⅲ models was respectively 62.7% and 44.2% higher than in Type I and Type Ⅱ models. This study indicates that seismic waves can affect deep earth, and, according to the results, seismic waves increase the permeability and change the flow rate patterns in a fractured rock mass.  相似文献