• Geomechanics and Engineering
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• v.14 no.4
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• pp.345-354
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• 2018

Currently, layered geogrid method (LGM) is the commonly practiced technique for reinforcement of slopes. In this paper the geogrid-box method (GBM) is introduced as a new approach for reinforcement of rock-soil slopes. To achieve the objectives of this study, a laboratory setup was designed and the slopes without reinforcements and reinforced with LGM and GBM were tested under the loading of a circular footing. The effect of vertical spacing between geogrid layers and box thickness on normalized bearing capacity and failure mechanism of slopes was investigated. A series of 3D finite element analysis were also performed using ABAQUS software to supplement the results of the model tests. The results indicated that the load-settlement behavior and the ultimate bearing capacity of footing can be significantly improved by the inclusion of reinforcing geogrid in the soil. It was found that for the slopes reinforced with GBM, the displacement contours are widely distributed in the rock-soil mass underneath the footing in greater width and depth than that in the reinforced slope with LGM, which in turn results in higher bearing capacity. It was also established that by reducing the thickness of geogrid-boxes, the distribution and depth of displacement contours increases and a longer failure surface is developed, which suggests the enhanced bearing capacity of the slope. Based on the studied designs, the ultimate bearing capacity of the GBM-reinforced slope was found to be 11.16% higher than that of the slope reinforced with LGM. The results also indicated that, reinforcement of rock-soil slopes using GBM causes an improvement in the ultimate bearing capacity as high as 24.8 times more than that of the unreinforced slope.

• Textile Coloration and Finishing
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• v.30 no.4
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• pp.245-255
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• 2018

In this study, cotton fabrics were coated with $TiO_2$ nanoparticles using 3-mercaptopropyltrimethoxysilane(3-MPTMS), which is highly reactive to cotton fabrics, as a medium, and the characteristics, antimicrobial properties, and photodegradation properties of the fibers were measured. The manufacturing process is as follows. (1) 3-MPTMS was added to isopropanol, and $TiO_2$ colloid was added to the mixture to prepare a solution. (2) Cellulose fibers were immersed in the prepared $3-MPTMS/TiO_2$ solution, stirred for 90 minutes at $45^{\circ}C$ in a constant temperature water bath, and dried thereafter. In order to identify the morphology of the cellulose fibers coated with $TiO_2$ nanoparticles, the surface was observed with a scanning electron microscope(SEM), and SEM-EDS was measured to identify the adhesion of $TiO_2$ nanoparticles. The SEM images showed $TiO_2$ nanoparticle and 3-MPTMS coated layers on the fibers and it was identified that $TiO_2$ nanoparticles were attached to the cellulose fibers. The antimicrobial activity of $3-MPTMS/TiO_2$-treated cotton fabrics was measured using a bacterial reduction method. $3-MPTMS/TiO_2$ cellulose fibers which was irradiated by ultra violet light, showed antimicrobial activity against Escherichia coli(ATCC 43895) and Staphylococcus aureus(ATCCBAA-1707) unlike unirradiated fibers. The cellulose fibers were stained with methylene blue and the photodegradation performance of the stained fabrics was analyzed. The stained fabrics showed high degradation performance with photolytic reactions of $TiO_2$ nanoparticles.