JOURNAL OF GEOTECHNICAL GEOLOGY (APPLIED GEOLOGY)
Year:2012 | Volume:8 | Issue:1|Papers Count:7

The Sistan River, located in southeast of the Sistan Plain in Iran and Afghanistan border, is a branch of the Helmand River and after passing a distance of around 72 km, reaches lake Hamoon in the Helmand. On this meandering river, numerous hydraulic structures have been made which whose major usage is in agriculture. Due to its gentle slope, construction of longitudinal and latitudinal structures, human interventions, and natural harsh, the morphology of the Sistan River has undergone many changes during the recent 50 years. The meanders of the river have longitudinal and latitudinal movements and these movements have made changes in the river path, bank erosion, land degradation, etc. In this research, the role of influencing factors in morphological changes of the Sistan River has been studied in a geomorphologic engineering scheme. In these evaluations, different intervals of the river have been checked based on geometrical parameters and it showed that the Sistan River has a stable status in all of the studied intervals. Then, sampling was done on river edge, over and under hydraulic structure sediments and the status of the erodibility of the edges and its reason have been investigated using sedimentology and geotechnical tests. In addition to the effects of the structures, human interventions and natural harsh, our investigations show that sediments of the edges of the Sistan River do not have enough elasticity and flow ability. Instead, they show non-plastic, low adhesion and shear strength behavior and appearance of tensile fractures against the flow, land damage, and threatening of surrounding villages by the flow of the water. Due to the importance of the Sistan River as the main source of drinkable and agricultural water in the Sistan region, based on the results of the geomorphologic engineering, major strategies in conducting engineering projects and organizing the river are necessary to be considered. Incorporation of geomorphologic engineering and river engineering studies will lead to protection of the river edges stability and lands around the river. In addition, it could be possible to utilize these lands efficiently with the minimum social stress and problems.

The most important goals of mechanization are decreasing the Production cost and increasing the quality and efficiency of coal Production. The most important factors that affect the potential of mechanization are seam inclination and thickness, seam uniformity, seam floor and roof conditions. These factors should be considered in coal mine mechanization analysis. In this study, it is important to develop a new index with respect to the mentioned factors. The coal seam mechanization can be classified into five classes such as very high, high, medium, low and very low using this new index. Finally, as a case study the coal seam mechanization of Alborz Sharghi plant was evaluated by using this new index.

One of the important parameters to describe and examine the production of the reservoir is the permeability. Permeability is conventionally estimated by using core and well logging data. Core operations are expensive. So, the possibility of performing them in all wells of a field does not exist. In recent years, the method of hydraulic flow units and Intelligent Systems such as neural networks to estimate the reservoir parameters has been very significant progress. This study has been done on the Dariyan Carbonate Formation which is reservoir in the Reshadat oil field. First, the flow zone index (FZI) has been determined by using the method of artificial neural networks and core data in existing wells and FZI has been generalized and calculated for wells without core. Finally, permeability has been estimated by the hydraulic flow units using artificial neural networks in the wells without core. The correlation coefficient between core permeability and permeability results calculated by combining the two approaches of hydraulic flow units and neural networks is R2=0.87 and by using artificial neural networks is R2=0.82 which shows the accuracy of the hydraulic units for improving the estimation of permeability.

The necessity of underground storage for natural gas has increased because of progressive request for suitable and low-pollution fuel as supersede of oil, increasing use of natural gas, better economy and safety than pipe lines and tanker trucks. This matter concern worldwide energy and economic markets such as Iran industry. In this study, it has been tried to assess and introduce several suitable sites for underground gas storage in central Iran (Semnan and Kuh-e-Gugerd) with regard to geology and structural geologic setting of Tertiary salt domes.In this area, salt domes have a core of massive and pure gypsum belonging to the Eocene-Oligocene. These domes were deposited in marine environment and covered by newer salts belonging to the Miocene (evaporates sections of the Upper Red Formation) that were deposited in playa and lake environments. Based on geological setting, satellite images, topographic sections and other data, salt domes in central Iran can be considered as suitable choices for underground gas storage. Complementary investigations such as exploration drilling operations and 2D and 3D geophysical studies are necessary for confirmation of these primary results.

The Aghajari Formation, known also as Upper Fars, extends throughout the Folded Zagros and its thickness in the type section is about 2966 m. To determine the sedimentary environment of this formation according to the lithofacies and architectural elements, a section, with a thickness of 2266 m, was measured in SW of Sarvestan in Fars Province. In this section, 17 lithofacies and 6 architectural elements were identified. The lithofacies were divided into two groups: a major group and a minor group. The major group consists of coarse-grained (Gh, Gp, Gt, Gcm, Gmg), medium-grained (Sh, Sp, St, Sl, Sm, Sr, Ss) and fine-grained (Fm, Fl, Fsm) lithofacies and the minor group consists of evaporate and mixed carbonate-terrigenous lithofacies. The identified architectural elements are CH, GB, SB, LA, SG and FF. According to the evidences due to lithofacies analyses and architectural elements and their incorporation, The Aghajari Formation in the studied section was divided into three parts. The sedimentary environments of the above-mentioned deposits, from top to the bottom, are gravelly meandering river, sandy-gravelly meandering river and ephemeral sandy meandering river. The most important sedimentary structures are horizontal bedding, cross bedding, load-cast, imbrications, graded bedding, turbulence traces, scour and fill and ball and pillow structures. Using some of these structures, the palaeo current direction in the studied area is measured as NW-SE during sedimentation. These data can be used in the interpretation of the basin and reconstruction of the palaeo geography in the local and regional scale.

Chamasiab watershed is located in the northeastern Khuzestan province. The sandstone unit of the Aghajari Formation has caused to be the formation of the sandstone aquifer in the area which discharges to the surface via Chamasiab spring. This study discusses the importance of fractures in the discharge of Chamasiab spring and recognizing of the area groundwater system as well. For this purpose, in the different parts of the area, the joints and fractures system has been measured. Also, the fracture density map has been prepared by using GIS and remote sensing (RS) techniques. The results show that fractures in the thick layers of sand stone have a major role in the sandstones permeability, and it has also been considered as the most important factor of Chamasiab spring discharge in the studied area. Spring discharge changes from 20L/Sec to 60 L/Sec in wet and dry seasons respectively. This reflects the permeability of sandstone in the area, and also shows that the spring response with respect to rainfall is high in the studied area.

The desert city of Kerman is based on a sand drift sheet with 10 meters thickness. Behind of these sand sheets, impermeable clay soils and silt are placed. Increasing the population of Kerman city and using attraction well for repulsing sewage is caused the rising of ground water level during 20 recent years. In the central district the level of ground water is raised to 1 or 3 meters. This conditions has environmental problems, beside it caused the saturation of sand drift sheets. This sand drift with the low number of SPT (Standard Penetration Test) and in saturation condition, have high liquefaction potential. Analyses shows that factor of safety (F.S.) of liquefaction result in the central district of the town in the seismic loading condition is less than 1 and as a result it has liquefaction potential. So with the high seismic potential of Kerman city, it's possible that occurring a strong earthquake, liquefaction damages many buildings and ancient structures in Kerman city.