Sharif Digital Repository

A fully coupled numerical analysis using Biot's theory with u-p formulation considering variable permeability during liquefaction is used in this study to simulate liquefaction induced lateral spreading phenomenon. A centrifuge test performed on liquefiable soil at Rensselaer Polytechnic Institute is simulated using the developed model. The numerical results are in good agreement with experimental observations. A number of numerical simulations under different geometric, site-specific, and ground acceleration parameters have been carried out in the course of this study. Based on the statistical analysis conducted on the results of 31 different models, a new relation is proposed for... 

It is generally accepted that a hydraulically induced fracture in the reservoir is approximately a plane fracture perpendicular to the direction of the in situ minor principal stress. However, field observations, in some cases, do not support the above traditional assumption. This is especially true when hydraulic fracturing technique is applied to the uncemented porous materials such as oil sands. In this article, the pattern of hydraulically induced fractures in oil sands and other geomaterials is discussed. Field observations and experimental investigation results are combined with the outcomes of the numerical simulations of hydro-fracturing in oil sands conducted by the authors to... 

The main objective of this paper is to provide comparative quantitative examinations on the capabilities of two-dimensional horizontal and pseudo-three-dimensional (3D) modelling approaches for simulating spatial and temporal variability of the flow and salinity in Lake Urmia, Iran. The water quality in the lake has been an environmentally important subject partly because this shallow hypersaline aquatic ecosystem is considered to be one of the largest natural habitats of a unique multicellular organism, Artemia urmiana. This brine shrimp is the major food source for many of the protected and rare shorebirds that visit the lake. A.urmiana can grow and survive in certain ranges of salinity,... 

A new and general procedure for history matching that uses streamline simulation and a gradual deformation technique has been proposed. Streamline trajectories define the major flow paths and help the algorithm to modify the reservoir model only in the regions that cause the mismatch between simulation results and field observations. The use of a gradual deformation technique enables the algorithm to remain constrained to reservoir geostatistics. It also reduces the number of independent variables in the optimization problem. In our algorithm, effective conductivities are defined along each streamline. The effective streamline conductivities are then adjusted using the values of measured and... 

Many oil reservoirs encounter asphaltene precipitation as a major problem during natural production. In spite of numerous experimental studies, the effect of temperature on asphaltene precipitation during pressure depletion at reservoir conditions is still obscure in the literature. To study their asphaltene precipitation behavior at different temperatures, two Iranian light and heavy live oil samples were selected. First, different screening criteria were applied to evaluate asphaltene instability of the selected reservoirs using pressure, volume, and temperature data. Then, a high pressure, high temperature filtration (HPHT) setup was designed to investigate the asphaltene precipitation... 

The Al-Askari shrine, located in Samarra, Iraq, is a remarkable example of a building with ancient Islamic architecture and construction that was heavily damaged by massive bombings. The bombings were carried out by two separate terrorist attacks in 2006 and 2007. This paper summarizes the important undertakings in the identification of shrine buildings in terms of structural and architectural background and characteristics, damage classification and monitoring, site conditions and material properties. Moreover, the shortcomings of a series of previously performed partial restorations are elaborated upon. The results and findings of this study can be utilized as database in other numerical... 

Gonbad-e Qabus, with a height of 52.8 m that makes it the tallest pure-brick tower in the world, located in the northern part of Iran, represents one of the most magnificent structures of the early Islamic centuries. This structure is still standing among the chaos of urban life and construction, catching the eyes of beholders even from far distances. This paper summarizes the historical and architectural background of this monumental structure and the important restorations carried out mainly in the past century. Various types of existing and potential structural and architectural damages are classified and elaborated in detail, and for each problem, a series of proposed solutions are...