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

• Journal of Korean Society for Quality Management
• /
• v.23 no.2
• /
• pp.68-79
• /
• 1995

Good estimation of the slopes of the mixture response function may be important as well as estimation of mean mixture response. It is possible to evaluate and compare several mixture designs with respect to the slope. A graphical method is proposed that allows us to evaluate a given design's support for the fitted model in terms of slope variance. We can plot variances of slopes along Cox direction according to existence of restriction of simplex region when comparing several different mixture designs.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.9
• /
• pp.38-45
• /
• 1996

The optical triangulation method has been used as a non-contact measuring method of three dimensional object whape. But this measuring method has narrow measuring range, non-linearity on steep slope surface and shadow effect. In this study, we discussed a new optical measurement method to overcome these kinds of demerits. The advantage of this new method is that it is possible to measure precisely the object shape having the steep slope surface without shadow effect. As exper- imental results, maximum displacement error was 200 .mu. m over the whole measuring when the incident angle on the object surface was within 60 degree.

• Geomechanics and Engineering
• /
• v.5 no.2
• /
• pp.143-164
• /
• 2013

Calculation of seismic displacements in reinforced slopes plays a crucial role in appropriate design of these structures however current analytical methods result indifferent values for permanent displacements of the slope. In this paper, based on limit equilibrium and using the horizontal slices method, a new formulation has been proposed for estimating the seismic displacements of a reinforced slope under earthquake records. In this method, failure wedge is divided into a number of horizontal slices. Assuming linear variations for tensile forces of reinforcements along the height of the slope, the coefficient of yield acceleration has been estimated. The simplicity of calculations and taking into account the frequency content of input triggers are among the advantages of the present formulation. Comparison of the results shows that the yield acceleration calculated by the suggested method is very close to the values resulted from other techniques. On the other hand, while there is a significant difference between permanent displacements, the values obtained from the suggested method place somehow between those calculated by the other techniques.

• Journal of the Society of Disaster Information
• /
• v.3 no.2
• /
• pp.147-169
• /
• 2007

This study investigates the reinforcing effects of the Multi-bar Spring nails with respect to the conventional Soil-nails in artificial slopes. Based on wide experience related to design and construction, soil nails have been widely applied to reinforce slope in the world. Multi-bar spring nails are one of the improved soil nailing methods. These method maximizes bending, shearing, pull-out resistance for those multi-nails, not unit nail, that are inserted in the borehole using special spacer at regular intervals. In addition, because cutting plane is confined effect resulting from a pressured plate at the end of the nails with compression spring equipment, slope stability is secured using MS-nailing method. Analyzing bending, pull-out, shearing condition of MS-nail, it was examined throughly elastic region, load transfer capacity, reinforcing effect on cutting plate of MS-nails. In addition, Pilot and laboratory tests, numerical analysis were carried out to verify the superiority of MS-nailing method. In case, MS nailing method is applied to reinforce artificial slope, it was analyzed that bending, pull-out, shearing resistance was increased more than existing nailing method was applied. In this study, it was shown that surface failure was more or less prevented using MS-nailing method, confining effect on cutting plane using spring stuck to flexible equipment.

• Journal of the Semiconductor & Display Technology
• /
• v.11 no.4
• /
• pp.43-48
• /
• 2012

The screen printing method is much used in the flat panel display field including the LCD, PDP, FED, organic EL, and etc. for forming the high precision micro-pattern. Also A number of studies of screen printing method has been conducted as the method for the cost down through the improvement of productivity. Because of being the dot printing method of the cylindrical shape not being the line printing method like the existing PDP barrier rib and phosphor, the pillar arrays using the screen printing method is deposited in the hemispherical type not being cylindrical shape in the existing printing process conditions. In this paper, the parameters were set on the screen printing device in order to deposit the cross-sectional shape with the cone or trapezoid shape of the pillar in depositing the pillars used the screen printing device for vacuum glazing. The cross-sectional shape slope of the pillar according to the parameters was measured. And analysis the effect of the screen printing process conditions on the cross-sectional shape slope of pillars based upon the result of being measured. The processing conditions were drawn to minimize the cross-sectional shape slope of pillar.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1997.09a
• /
• pp.137-146
• /
• 1997

• Journal of Korea Water Resources Association
• /
• v.41 no.5
• /
• pp.503-515
• /
• 2008

In this study we calculate discharge by slope-area method using continuously observed water level data and analyse the results. This study is performed in the Dalcheon river reach of 960 m length including riffles and a pool, which is located downstream of the Goesan Dam. Three values of roughness coefficient are applied to discharge calculation, which are established using bed material size analysis. Another roughness coefficient value obtained from the river improvement plan is also used. Calculated discharges by slope-area method are compared with dam discharges. Relative difference from dam discharges appears to be largely affected by roughness values and a value of 0.042 or more seems most suitable for the entire study reach. Smaller roughness value is suitable to the reach which has gentler water surface slope than mean channel slope of the entire study reach, while a larger value to steeper reach. In case roughness value is set considering overall slope of the channel, it is desirable to select the entire calculation reach including both gentler and steeper sub-reaches. Since relative difference becomes nearly constant at over 500 cms, in case that verification of applied roughness is conducted with other directly measured discharge, accuracy of measurement by slope-area method for larger discharge may be improved.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.722-726
• /
• 2010

Inventory survey is process collecting data about cut slope. It's different from inspection. It contains not only basic information about cut slope, especially location, GPS positioning, height, length, weathering, joint direction, water conditions but also level of danger and damage. Collected data are being used get at status about cut slope along national roads. And It helps judging about priority of detailed investigation. According to results of analysis, we found better method about maintenance of cut slope. Later on, if inventory research is finished, we will understand characteristics of collapse slopes.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.135-142
• /
• 2000

A framework alternative to that of classical slope stability analysis is developed, wherein the soil mass is treated as a continuum and in situ soil stresses and strengths are computed accurately using inelastic finite element methods with general constitutive models. Within this framework, two alternative methods of stability analysis are presented. In the first, the strength characteristics of the soil mass are held constant, and the gravitational loading on the slope system is increased until failure is initiated by well-defined mechanisms. In the second approach, the gravity loading on the slope system is held constant, while the strength parameters of the slope mass are gradually decreased until well-defined failure mechanisms developed. Details on the applying both of the proposed methods, and comparisons of their characteristics on a number of solved example problems are presented.