Showing 11 results for Nera
Volume 1, Issue 2 (11-2003)
Abstract
(Paper pages 157-178) Because of transportation of the sedimentary materials from the surface of continents,the continental environments have a significance importance among the other river environments .The quantitative study of these environments is done on the basis of their driange basins. This study is also done on the basis of the same aspect, with a special attention to the influences of the sub-basin on the accumulation of the heavy minerals. The proposed basin is the NW part of Dez basin that is located between two different geological zones, called Sanandaj–sirjan and Zagros crush zone.These geological zones are seperated by Boroudjerd- Dorood plane.The strahler grading order was used for ranking. Due to our knowledge, third – order sub- basins were selected as concentred places of heavy minerals for further studies. The main basin of the proposed area was a six –order type, that is a relatively high degree. Four drinage anomalys were seen in this area, that one of them was affected by the lithology characters of area and other were affected by the faults. The results show that faults have significant rules on the formation of third- order sub- basin. The proposed area has a suitable maturation, due to the high rank of it and existence numerous of the low- order sub- basins of the higher altitudes,so that number of the high – order sub-basins is 25 % relative to low-order sub – basins.Further studies showed that, the main heavy minerals are andalusite and kyanite in the third- order sub – basins that belong to sanandaj- sirjan zone .Finally, it was revealed that the six – order basin was a consequent type.
Volume 1, Issue 3 (3-2004)
Abstract
(Paper pages 255-270) The groundwater protection is important in order to have a good management of water resources. The Ghazvin plain situated in west of Tehran, Iran has a critical situation in which the groundwater level declines and aquifer pollution has been observed in recent years. In this research, for evaluating the groundwater vulnerability, DRASTIC index has been used for this plain. Then, a Geographic Information System (GIS), ILWIS has been used to create a groundwater vulnerability map. The results of this study estimated DRASTIC value to be in the range of 35-108 using general DRASTIC value, almost 11% of the study area was recognized to have low feasibility, 43% moderate and 37% high and 10% very high feasibility for pollution. The DRASTIC results show a good adaptation between increasing the nitrate rate and the DRASTIC index
Volume 4, Issue 2 (5-2011)
Abstract
The main objective of this research is to provide information about the effects of mineralogical characteristics of aggregates on concrete properties. Crushed aggregates were selected with different petrographics from different resources. Aggregates such as, Marble, Dolomite, Tuff, Granite, Genasis, Basalt, Andesite, Lumashele, Sand Stone and Diorite which have different chemical, physical and mechanical properties were used in this study. The results of the study showed that physical and mechanical properties of minerals control properties of concrete and undesirable properties of concrete influenced with which of mineral. Also, the results indicated that aggregates with flaky and elongated minerals subjected to weathering have a great effect on undesirable properties of concretes. The highest uniaxial compressive strength (33 MPa) at 28 curing days was measured in the specimens prepared with dolomite aggregates while the lowest strength (13 MPa) was measured in the specimen prepared with lumashele aggregates at the same age.
, Ar Taleb Beydokhti, A Asiabanha,
Volume 6, Issue 1 (11-2012)
Abstract
Slake durability of rocks is an important engineering parameter for evaluating deterioration of rocks in chemical and physical agents that are related to mechanical properties of rock. The main purpose of this study is to assess the influence of the number of drying and wetting cycles under variable pH conditions and controls of mineralogical composition on durability. For this purpose, five different types of tuff were selected from different parts in north Qazvin city. The samples were subjected to multiple-cycle slake durability testing with different pH values solution. Also the slake durability tests in saturated condition on samples, petrographical analyses and basic physical - mechanical test were performed. In addition, to assess the influence of mineralogical composition on durability, the mineral contents of the original material and the material passing from the drum of the slake durability apparatus after fifteen cycles were also determined by XRD analyses. It was concluded that the slake durability of tuff is independent of the pH in acidic solution circumstances. Mineralogical composition, fabric and weathering rate are considered to have a greater influence on the slake durability of tuff. A strong relationship between the point load strength and the fifteenth-cycle slake durability index is found in the rock types studied.
Gr Lashkaripour, Iman Aghamolaee, M Ghafoori,
Volume 7, Issue 2 (3-2014)
Abstract
Marl rocks are from weak rocks which cause some problems due to high swelling and efflorescence capability, low resistance and durability in construction of engineering structures. Creation of these problems is due to inadequate recognition of engineering geology properties of these rocks. Hence, in this research for determination of the physical and mechanical parameters of marl rocks of Safa dam site, Aterberg limits, density, porosity and moisture percent, uniaxial compressive strength (UCS), direct shear, swelling and three axial compressive strength tests and X-ray diffraction (XRD) and X-ray fluorescence (XRF) analyses were performed on available samples from excavated bores. Results of experiments indicate that the type and contents of minerals and percentage of calcium carbonate in marl rocks, especially clay minerals are effective factors on engineering geology properties of these rocks
Arash Hashemnejad, M Ghafoori, Gh Lashkaripour, S Sadeghazali,
Volume 8, Issue 2 (11-2014)
Abstract
One of the tests that is used for the characterization of soil abrasivity, is LCPC test. LCPC test device is designed for measuring the wear particles as small as pebbles (4-6.3 mm). In this study, some of the most important abrasive minerals were collected from different parts of Iran for analyzing the effect of the geological parameters on the ability of abrasive minerals. Firstly, amount of index minerals abrasivity is measured according to three standards of AFNOR P18-553, AFNOR P18-579 and AFNOR P18-560 that are the preparation of samples for testing, procedure of laboratory tests and analysis of grain size with laboratory sieves. The effect of geological parameters affecting the wear rate of the sample, including five parameters of shape, size, angularity and saturation rate of the environment, has been studied. The effectiveness of these parameters on the abrasivity of samples are studied according to NF ISO 5725 relating to usage of statistics, the accuracy of test method, the repeatability and the ability to reproduce a standard way of testing within laboratory (based on classification index X 06-041). Finally, after ensuring significant effect of these parameters on the abrasivity of minerals by help of SPSS, abrasivity rates for types of minerals that have the hardness below 7 in the Mohs hardness scale, have been predicted.
Mh Ghobadi, M Kapelehe ,
Volume 10, Issue 4 (5-2017)
Abstract
Durability is a significant parameter in engineering geology and it shows the extent of the degradability of rocks as the result of mechanical and chemical breakdowns. This phenomenon is closely linked to the composition, porosity and texture of rocks. To understand the relationship between the chemical composition of rocks and their durability the mineralogical properties of the rocks along with durability tests under both acidic and alkaline pH environments were determined. Five samples of limestone and three samples of marl were analyzed. The results revealed that rocks containing high levels of CaCo3 were affected in the acidic conditions while rocks containing high levels of SiO2 were not affected by variance in the pH of the environment. These second groups of rocks were more dependent on the texture of their constituent minerals.
Hamed Rajabzade, Hamid Mehrnahad,
Volume 12, Issue 1 (8-2018)
Abstract
Introduction
The effect of surface geology on seismic movement is known and acceptable and this effects can consider important factor in movement resulting from earthquake. studying intensity and dispersal of recent decade earthquake destruction indicated importance of construction effects and surface geology conditions more than ever. From view point of engineering, earthquake importance is in light of effects that these earthquakes is created in construct such as dams, powerhouses, bridges, residential areas and industrial installations that in most cases, this constructs are building not only on rack mass surface but on earth surface, e.g . alluvial layers placed on bed stone. The effect of soil layers on earthquake waves is result of complex processes that this effect can exist as dynamic support under stability soil conditions that is called as intensification from it.
Material and methods
There are multiple methods in order to determining effect of construct and affecting in on earth potent movement features, that among them are covered less-cost numeral methods and more site output and beacuse of reason are using from these methods in order to analyzing respond to earthquake vibrations. In this paper try to using data resulting from drining 5 boreholes on Tabas city construction are studying the effect of and also comparing numeral methods of analyzing building such as equivalent linear and non-linear analysis for earthquake return periods of 75, 475, 2475 using NERA and EERA softwares.
Results
Taken together reinforcement rate and also maximum velocity in earth surface can explain that Dehshak region and Tabas center areas include more intensification conditions. On the other hand, south zone of Sarasyab sector and then Imamzade area include higher solidity and least intensification. Based on done studies are suggested to guided urban development programm more toward Hossein – ebne - Mousakazem Emamzadeh in order to exert from more suitable buildings. Also, regarding to EERA high-leval evalution and non-linear soil bahavior for earthquake with 2475 high return period is used from NERA software for analyzing construction effect to obtain maxium more realistic surface velocity .
./files/site1/files/121/Rajabzadehi_Abstract(1).pdf
, , , ,
Volume 15, Issue 3 (12-2021)
Abstract
In this study, due to the landslide in schist rocks, in the wall of Mouteh gold mines, including of the eastern wall of ChahKhatoon mine, it is important to identify the effective factors. Therefore, due to the diversity of schists in Chah Khatoon and Sanjadeh gold mines (two active mines in Mouteh Complex), to survey the mineralogy of schist rocks in Moteh gold mine has been done by identifying important factors in changes in rock strength. Cosequently, 10 schist samples from walls of these mines were considered for mineralogical, XRD studies. In the next step, these schists were subjected to uniaxial compressive strength (UCS) and Brazilian tests to estimate the mechanical properties and quality of rock mass in different zones of mineral walls. The results showed that the UCS and Brazilian index in these schists are directly and inversely related to the SiO2 and Al2O3 contents of the rocks, respectively, as well as the secondary structures.Some factors such as the presence of secondary structures, continuous surface area, particle size, and mineralogical composition play an important role in the failure modes of these rocks. UCS and Brazilian strength of schists vary from 10 MPa to 72 MPa and 1.9 to 10.2 MPa, respectively. The lowest UCS occurs in strongly weathered rocks with low silica content. However, the type of clay minerals is effective in the stability of the mineral wall. Considering the presence of montmorillonite clay mineral in the eastern wall of Chahkhatoun mine, the rock resistance is moderate despite the high percentage of silica. UCS values of wet and dry rock samples containing muscovite and montmorillonite clay minerals were more different from those of other rocks. In this regard, the rocks with Illite clay minerals are more resistant than Smectite and montmorillonite minerals. In general, the resistance of schists depends on various factors such as mineralogy, which is of great importance because of its involvement in the formation of secondary structures.
./files/site1/files/%D8%AC%D8%B9%D9%81%D8%B1%DB%8C_%D9%82%D8%B1%DB%8C%D9%87.pdf
Eng. Zahra Soleimani, Dr. Ebrahim Rahimi, Dr. Houshang Khairy,
Volume 18, Issue 1 (5-2024)
Abstract
This article deals with the strength evaluation of concrete obtained by adding different percentages of three types of nanominerals, including nanocalcite, nanobarite and nanofluorite. To measure the velocity of ultrasonic waves and compressive strength of concrete, 15×15×15 cm cube samples were prepared with 7-, 28- and 90-days curing. 10 types of mix designs with 0.39 water-cement ratio, including the control sample (without additives) and the samples with 0.5, 0.75 and 1% nanominerals were subjected to the mentioned tests. The results showed that the addition of nanocalcite, nanofluorite, and nanobarite with values of 0.75%, 1%, and 0.75%, respectively, have the highest compressive strength compared to the control sample. Although these do not have pozzolanic properties, they play a positive role in increasing the concrete strength by filling concrete voids and due to their high specific gravity, increasing concrete density.
Dr Sepideh Shakour, Dr Manouchehr Chitsazan, Dr Seyed Yahya Mirzaee,
Volume 18, Issue 2 (9-2024)
Abstract
One of the appropriate ways to prevent groundwater pollution is to identify vulnerable aquifer areas. The Dezful-Andimeshk Plain has two landfills that do not comply with the necessary standards for waste disposal and a river that recharges the aquifer, which can be potential pollutants for the aquifer. Therefore, evaluating the pollution potential of this aquifer is considered a necessity. To achieve this goal, for the first time in this area, the assessment of the aquifer pollution potential was carried out based on the intrinsic vulnerability (DRASTIC) and specific vulnerability (DLR), and finally, the potential contamination (PC) in the region was evaluated.. Based on the results, the value of the inherent vulnerability index ranges from 106 to 162 and has two vulnerability classes: moderate and high. The high vulnerability is related to the western margin of the plain and near the outlet of the plain, as well as in the middle of the plain with a northeast-southwest trend. The low vulnerability is associated with the northern and southern parts of the region. The specific vulnerability index ranges from 25 to 75, which, based on expert opinion, is classified into two classes: low and medium vulnerability. The highest intrinsic vulnerability is in the middle of the plain and around the Dez River. According to the results, the aquifer's PC ranges from 130 to 207 due to specific and intrinsic vulnerabilities. It is classified into three classes: medium, high, and very high, mainly affected by the river, land use, soil, and hydraulic conductivity.