Predicting the Isotropic Volumetric Compression Response of Hydrating Cemented Paste Backfill (CPB)     

Jafari  Mohammadamin  Grabinsky  Murray 《Geotechnical and Geological Engineering》2022,40(9):4821-4836

Geotechnical and Geological Engineering - Deep and high-stress mining results in stress transfers onto the previously placed backfill, and mines have recorded several MPa induced backfill stresses....  相似文献   

Influence of Load Path and Effective Stress on One-Dimensional Deformation of Cemented Paste Backfill (CPB) During Deposition and Curing     

Shahsavari  Mohammad  Jafari  Mohammadamin  Grabinsky  Murray 《Geotechnical and Geological Engineering》2022,40(4):2319-2338

Geotechnical and Geological Engineering - Pore water pressure and effective stress development within cemented paste backfill (as one of the most popular local and regional underground mining...  相似文献   

Study on the Erodibility and Mechanical Resistance of Mulches Prepared from Micro Silica–Cement Mixtures     

Naghizade Asl  Fateme  Asgari  Hamid Reza  Emami  Hojat  Jafari  Mohammad 《Geotechnical and Geological Engineering》2021,39(5):3347-3360

Geotechnical and Geological Engineering - Mulching is fastest strategy to control sand dune movement in arid and semiarid areas. In the present study the effect of micro silica- cement mixture was...  相似文献   

Reduction of environmental pollution through optimization of energy use in cement industries   总被引：1，自引：1，他引：0  

A. R. Karbassi Ph.D.  H. R. Jafari Ph.D.  A. R. Yavari Ph.D.  H. Hoveidi  H. Sid Kalal Ph.D. 《International Journal of Environmental Science and Technology》2010,7(1):127-134

Industrial development has lead to higher energy consumption, emission of greenhouse gases, as well as air pollutants. Cement factories play an important role in over all greenhouse emissions. This study aims to investigate the role of Iranian cement industries and their contribution of greenhouse gases contribution. The measured emission factors for oil and fuel gas shows that carbon dioxide contribution from fuel oil based cement industries is almost 2.7 times higher than gas based cement factories. The strength, weakness, opportunity and threat technique analysis showed that the best strategy to combat greenhouse gases from Iranian cement factory is to implement energy efficiency measures. Further, strategic position and action evaluation matrix analysis indicates that Iranian cement industries fall within invasive category. Therefore, exploitation of opportunities must carefully be used. One of these opportunities is the utilization of financial assistance provided by clean development mechanism. The results show that replacement of ball mills with vertical roller mill can reduce the electricity consumption from 44.6 to 28 kWh/ton. As a result of such substitution about 720 million kWh/y of electricity would be saved (almost a power plant of 125 MW capacities). Though implementation of new mills may not be economic for the cement industries’ owner, but the overall gain for the government of Iran will be about US$ 304 million. If the duration of such efficiency measure is considered as about 12 y, then the overall CO₂ reduction/phase-out would be around 4.3 million tons.  相似文献   

Burdigalian–Serravalian calcareous nannoplanktons from Qom Formation, North-Center Iran     

Fatemeh Hadavi  Marziyeh Notghi Moghaddam  Hoda Mousazadeh 《Arabian Journal of Geosciences》2010,3(2):133-139

The aim of this study is to determine calcareous nannofossil species found in Kamar-Kuh area and demonstrate this use for biostratigraphic studies. The Qom Formation is widely distributed in Kamar-Kuh section and has nine members(a–f). In this study, 12 samples were taken and prepared with smear slide. Some of the determined species are listed below, and some of them are photographed by light and scanning microscope. According to obtained nannofossils, 16 species, nine genera, and six families were determined. Obtained nannofossils indicated age of Burdigalian–Serravalian (middle Miocene) for this section.  相似文献   

The source of fluoride toxicity in Muteh area,Isfahan, Iran   总被引：1，自引：0，他引：1  

Behnam Keshavarzi  Farid Moore  Ali Esmaeili  Fatemeh Rastmanesh 《Environmental Earth Sciences》2010,61(4):777-786

Endemic dental fluorosis has been observed in most inhabitants of three villages of Muteh area, located in northwest of Isfahan province, with mottled enamel related to high levels of fluoride in drinking water (1.8–2.2 ppm). Forty-seven groundwater samples from six villages were collected and fluoride concentrations along with physico-chemical parameters were analyzed. Fluoride concentration in this area varies from 0.2 to 9.2 mg/l with highest fluoride level at Muteh gold mine (Chahkhatun mine). Fluoride concentration positively correlates with pH and HCO₃ ⁻ indicating that alkaline pH provides a suitable condition for leaching of fluoride from surrounding rocks. The district is mainly covered by three lithological units, namely, metamorphic and granite rocks, alluvial sediments, and carbonate rocks. Factor analysis shows that parameters can be classified into four components: electrical conductivity (EC), total dissolved solids (TDS), Cl⁻, Na⁺ and K⁺, pH and F⁻, SO₄ ²⁻and Mg²⁺, HCO₃ ⁻ and Ca₂ ⁺. The groundwaters from the three geological units were compared using Mann–Whitney U test. The order of median fluoride concentration is: metamorphic and granite rocks > alluvial sediments > carbonate rocks. Hence, the fluoride content is most probably related to fluoride-bearing minerals such as amphibole and mica group minerals in metamorphic and granitic rocks. The concentration of fluoride in drinking water wells located near the metamorphic complex in Muteh area is above 2 ppm.  相似文献   

Zinc extraction from Iranian low-grade complex zinc–lead ore by two native microorganisms: Acidithiobacillus ferrooxidans and Sulfobacillus   总被引：2，自引：0，他引：2  

S.M. Mousavi  S. Yaghmaei  M. Vossoughi  A. Jafari  R. Roostaazad 《International Journal of Mineral Processing》2006,80(2-4):238-243

A mesophilic iron oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated (33 °C) from a typical, chalcopyrite concentrate of the Sarcheshmeh copper mine in the region of Kerman located in the south of Iran. In addition, a thermophilic iron oxidizing bacterium, Sulfobacillus, has been isolated (60 °C) from the sphalerite concentrate of Kooshk lead and zinc mine near the city of Yazd in the center point of Iran. Variation of pH, ferrous and ferric concentration on time and effects of some factors such as temperature, cell growth, initial ferrous concentration and pH on bioleaching of low-grade complex zinc–lead ore were investigated. The results obtained from bioleaching experiments indicate that the efficiency of zinc extraction is dependent on all of the mentioned variables; especially the temperature and initial Fe(II) concentration have more effect than other factors for these microorganisms. In addition, results show that the maximum zinc recovery was achieved using a thermophilic culture. Zinc dissolution reached 58% with Sulfobacillus while it was 51% with A. ferrooxidans at pH = 1.5, initial Fe(II) concentration = 7 and 9 g/L for A. ferrooxidans and Sulfobacillus, respectively, after 30 days.  相似文献   

Experimental Study of Mechanical Behaviour of Rock Joints Under Cyclic Loading   总被引：3，自引：5，他引：3  

M. K. Jafari  F. Pellet  M. Boulon  K. Amini Hosseini 《Rock Mechanics and Rock Engineering》2004,37(1):3-23

Summary Evaluation of the effects of small repetitive earthquakes on the strength parameters of rock joints in active seismic zones is of interest of the designers of underground constructions. In order to evaluate these effects, it is necessary to study the behaviour of rock joints under dynamic and cyclic loadings. This paper presents the results of a systematic study on the behaviour of artificial rock joints subjected to cyclic shearing. More than 30 identical replicas have been tested using triaxial compression devices under different conditions of monotonic and cyclic loading. At the first stage a few samples have been tested in monotonic loading modes under various confining pressures and rate of displacement. In the second series of tests, small cyclic loads were applied on the samples for increasing number of cycles, frequency levels and stress amplitudes. These were then followed by monotonic loading again. The variations of maximum and residual shear strengths for each test have been studied. The results show increase of shear strength as a result of the increase in confining pressure and they display decrease of shear strength due to the increase of rate of loading, number of cycles, frequency levels and stress amplitudes.  相似文献   

Post-Cyclic Undrained Behavior of Compacted Composite Clay Subjected to Various Cyclic Loading Paths     

H. R. Tavakoli  A. Shafiee  M. K. Jafari 《Geotechnical and Geological Engineering》2011,29(6):1085-1097

Using a sequential procedure of undrained cyclic and post cyclic tests, the strength and stiffness degradation characteristics of compacted composite clays are studied immediately after various cyclic loading paths by triaxial and hollow cylinder tests. The effects of cyclic loading paths, sand contents, cyclic loading amplitude and confining pressure on the post-cyclic mechanical behavior of the composite clays are evaluated. The results point out different peculiarities which can be of interest in assessing the mechanical behavior of the composite clays under post seismic shaking. The results show that effect of cyclic loading on post cyclic pore water pressure build-up is significant when pore water pressure build-up is considerably lower than the associated value in monotonic loading. The effect of sand content and cyclic loading path on degradation of stiffness is more remarkable than shear strength. Test results also reveal that the effect of sand content on the post cyclic pore water pressure build-up is minor. However, when the aggregate content increases the shear strength increases.  相似文献   

Relationship between soil erosion, slope, parent material, and distance to road (Case study: Latian Watershed, Iran)     

Shirin Mohammadkhan  Hasan Ahmadi  Mohammad Jafari 《Arabian Journal of Geosciences》2011,4(1-2):331-338

Soil erosion is the dominating factor of damaging roads in Iran. Roads are a critical component of civilization. Developing and maintaining the economic activity that is vital for the quality of modern life would be difficult without roads. Accelerated erosion and increased sediment yields resulting from changes in land use are critical environmental problems, and one of the important changes is road construction. Construction and condition of roadways are associated with direct and indirect impacts on soil erosion. This paper presents the relationship between soil erosion and some characteristics such as distance to roadway, slope, and parent material in Latian Watershed, Tehran Province, Iran. Soil erosion map was interpreted using aerial photos and GIS technology. Buffer zones, subdivided into 12 strips, each 0.2 km wide, which were located alongside roadway. The distribution patterns of various types of erosion were also identified by GIS by overlaying road buffer strips and soil erosion map. The results show that soil erosion landform such as land slide, badland, bank erosion, channel erosion, etc. found in buffer zones along both sides of roads.  相似文献