排序方式： 共有64条查询结果，搜索用时 15 毫秒
61.
In recent years, there has been a rapid growth in the two industrial port cities of Iran, the port of Mahshahr and the port of Imam Khomeini. In spite of their importance for the economy, the two cities require monitoring and assessment from an environmental and human health perspective. In this study, environmental quality and heavy metals pollution of soils influenced by human activities were investigated. A total of 30 soil samples were collected and subjected to detail physicochemical characterization. The results showed high levels of heavy metals in the urban soils of port of Mahshahr (POM) and elevated respective levels in surface soils of the port of Imam Khomeini (PIK) with Ni being significantly higher than those in POM. The integrated pollution index (IPI) values of metals ranged from 1.22 to 1.87 in POM and 1.52 to 3.31in PIK, 50% of soil samples in PIK were classified as highly polluted, and all of the soil samples in PM were classified as moderately polluted. These results are in accordance with Enrichment Factor (EF) values, which showed the role of anthropogenic activities in the soil heavy metal enrichment. Moreover, the highest potential ecological risk index (RI) was found in the sites of petrochemical industries in PIK indicating serious metal contamination. Statistical analysis showed that heavy metals were mainly controlled by human activities. The results showed more dense industrial activity in PIK is responsible for higher pollution. This study establishes a benchmark against which future monitoring and remediation programs can be based on. Because of proximity to the Persian Gulf, continued the release of contaminants into the region, could have adverse biological health effects. 相似文献
62.
Seyed Esmaeil Mousavi 《Geotechnical and Geological Engineering》2018,36(1):77-87
Silica fume is identified as a pozzolan and supplementary cementitious material that can utilize to improve the mechanical properties of stabilized soil with cement. Silica fume wherein mixes with cemented soil in a proper dosage, it is susceptible to induce pozzolanic effect in cemented soil due to its fineness and high content of SiO2 and Al2O3. The pozzolanic effect is vital to ensure ongoing strength of stabilized soil with cement. Up to now, stabilization of clay with cement and silica fume is not completely explored. This paper investigates: (i) the capability of utilizing the silica fume as a supplementary material for cement to maximize the filler and pozzolanic effects of compacted and stabilized soil (ii) the mechanical properties of compacted and stabilized clay with various proportions of cement and silica fume. For this purpose, a total of 120 untreated and stabilized soil admixtures were prepared by replacing ordinary Portland cement with silica fume. The influence of partial replacement of cement with silica fume on the bearing capacity, shear and compressive strength of compacted and stabilized soil was investigated. To achieve such aims, the stabilized soil specimens were examined in laboratory under direct shear, unconfined compression and California bearing ratio tests. Based on the findings of this paper the 28-day UCS of the stabilized soil with 2% partial substitution of cement with silica fume is almost 3.5-fold greater than that of the untreated. It was found that the optimum mix design for the stabilized soil is 6% cement and 2% silica fume. In conclusion, a notable discovery is that the partial substitution of cement with 2% silica fume in the optimum mix design significantly refined the pore spaces as a result of pozzolanic activity and filler effect of silica fume. 相似文献
63.
A comprehensive seismic risk assessment has been performed for the existing route of the 3rd Azerbaijan natural gas buried pipeline in Iran. The major active seismic sources along the pipeline were identified and the geometrical parameters as well as the seismicity rates were determined. The seismic hazard assessment of the ground vibrations along the pipeline was performed in the framework of the Probabilistic Seismic Hazard Analysis using the CRISIS 2007 software. All of the components of the gas pipeline along the route were identified and the corresponding fragility functions are established through the methodology described in the HAZUS guideline (HAZUS MH MR4 Technical manual 2007 Department of homeland security emergency. Preparedness and Response Directorate, FEMA). A detailed cost analyses was taken into consideration based on the expert opinions in the National Iranian Gas Company, in order to provide more practical loss model for the pipeline route. Also, a simple method is suggested in order to account for the vent gas in the total loss estimation. The spatial analysis of the hazard function layer in combination with the loss model layer, in Geographical Information System (GIS) platform, reveal the financial consequences of different earthquake scenarios. 相似文献
64.
Slake durability of rocks is a vital engineering geological property of rock materials that has an important role in the promotion of slope stability, evaluation of rock materials, as well as the estimation of stone degradability. This parameter is related to such factors as mineralogy, physical characteristics of rocks, and the environmental conditions. A major part of south and southwestern Iran embraces the Aghajari Formation whose sandstones are used to form the foundations for some structures in Khouzestan province where they are being extensively used as aggregate(s). In this paper, tests of mineralogical examinations, physical properties, and slake durability of sandstones from Ahwaz and Haftkel anticlines were administered in order to assess the durability and degradability of these rocks. The rock durability of each type was evaluated to be up to 15 cycles in acidic and alkaline watery environments and salt aqueous solutions. The results showed that durability of sandstones under study is related to their petrographical and physical characteristics. The durability index of the sandstone samples was decreased by pH reduction and by increasing the concentration of aqueous solutions. The durability index of Ahwaz samples, too, was decreased in basic solutions while this index increased for Haftkel sandstones with the increase in the pH of solutions. Also, the obtained results illustrated that durability index decreased with the increase in the number of cycles. Based on the results, all sandstones show that the durability in sodium sulfate solution is much lower than that for the sodium chloride. Moreover, the slake durability index of the sandstones is decreased with an increase in the concentration of aqueous solutions. As a final statement, the Ahwaz sandstones show lower resistance to weathering processes than Haftkel sandstones; therefore, the use of rocks as building stones is not recommended here. 相似文献