Assessing the Impacts of Landfills on Environment using Geotechnical Factors, ‎Case study: Landfill of Quchan

Increased waste production due to population growth and improper landfilling is one of the most significant problems in urban communities. Environmental impact assessment is one of the tools that has been introduced to predict and reduce the destructive and harmful effects of construction projects. Therefore, in the present study, the impacts of unprincipled exploitation of Quchan’s landfill on the environment (EIA) was assessed using existing reports and satellite images, field studies, and considering the influential factors of environmental geotechnics in Iranian matrix. Analyzing the Iranian matrix shows that the number of effects and consequences of the negative algebraic mean is equal to 3 and 5, respectively. However, the negative effect and consequence less than -3.1 in the column and row are related to leveling and ground preparation, bed rupture and wall stability, respectively. More investigation on geotechnical parameters indicated that the factor of safety (FS) of gravel walls needs improvement. It was shown that in Quchan’s landfill, in case of excavation with a slope of less than 35 degrees and excavation height of about 4 meters, the existing trenches will not slip. Therefore, the necessary modification and improvement is necessary for the wall retaining and appropriate results and solutions have been provided to improve the conditions

Strength properties of soft clay treated with mixture of nano-SiO2 and recycled polyester fiber

This paper investigates the effect of recycled polyester fiber, produced from polyethylene (PET) bottles, in combination with nano-SiO2 as a new stabilizer to improve the mechanical properties of soils. We intend to study the effect of adding nano-SiO2 and recycled polyester fiber on soil engineering properties, especially the shear strength and unconfined compressive strength (UCS), using clayey soil with low liquid limit. Three different combinations of fiber-soil ratios ranging between 0.1% and 0.5% as well as three different combinations of nano-soil ratios ranging between 0.5% and 1% are used. The shear strength and UCS of treated specimens are obtained from direct shear test and unconfined compression test, respectively. Results of this study show that the addition of recycled polyester fiber and nano-SiO2 increases the strength of soil specimens. Both the shear strength and UCS are improved by increasing the contents of recycled polyester fiber and nano-SiO2 in the soil mixture. The increase in the nano-SiO2 content leads to a reduction in failure strain, but the increase in the content of recycled polyester fiber leads to an increase in failure strain. The increase in the contents of recycled polyester fiber and nano-SiO2 leads to an increase in elastic modulus of soils. Based on the test results, the addition of recycled polyester fiber improves the mechanical properties of soils stabilized with nano-SiO2 as well as the recycled polyester fiber has a positive effect on soil behaviors

Shaking Table Test on Mitigation of Liquefaction-Induced Tunnel Uplift by Helical Pile

The tunnels located in the shallow depths of loose saturated sand are significantly prone to liquefaction-induced uplift. Research works are, therefore, in progress to propose efficient techniques for mitigating uplift. In this study, 1 g physical modeling was used to assess the performance of helical piles for decreasing liquefaction-induced uplift. The effects of pile length, number of pile helixes, and the pile spacing in plan view were investigated. The uplift mechanism of the tunnel and helical pile system was also analyzed. The results demonstrate that the penetration of the helical piles into the dense layer underlying the superficial liquefiable sand has decreased tunnel uplift significantly. However, excessive close pile spacing along the tunnel resulted in shear surface interference, and the efficiency of the excessive number of helical piles decreased significantly. The detailed view of the uplift mechanism showed that utilization of the piles extended the transition phase of uplift during shaking. Helical piles can efficiently restrict the possibility of rapid uplift of the tunnel and shorten the duration of the primary uplift phase.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin

Effects of electrokinetic phenomena on the load-bearing capacity of different steel and concrete piles : a small-scale experimental study

To date, the electrokinetic (EK) method has only been used to increase the bearing capacity of steel piles. This study analysed the impact of EK on the bearing capacity of reinforced cement concrete piles (RCCP), reinforced lime-cement concrete piles (RLCCP), and steel piles located in kaolin clay. The performance of four different cathodes was also evaluated, and the iron electrode was found to be the most effective cathode for use in the EK process. Unlike RLCCP, the bearing capacity of 7 day cured RCCP with 5 day EK decreased due to corrosion in the pile body. However, the addition of lime to RCCP significantly increased the pile bearing capacity by 57.8% with 8 day EK and prevented damage and corrosion in the pile body. It is concluded that EK can effectively increase the bearing capacity of both metallic and even concrete piles