• Tunnel and Underground Space
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• v.18 no.1
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• pp.20-32
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• 2008

The study shows a method called a square-inventory method, which is a better and faster method than scanline survey and window method for an analysis of slope stability. The study area is located in the Changri area, Boeun-Gun, Chungbuk, and consists of many formations of the Okcheon Supergroup. Various types of failure are observed from the phyllite including the rocks in the study area. The physical properties of meta-sedimentary rocks are that minerals of the rocks are composed of microcrystalline quartz and sericite, which are arranged parallel to bedding (or schistosity) and crenulation cleavage. Therefore, such properties affect geotechnical ones of the rock. The slope stability are analyzed by selecting 3 areas, each of which are divided into 2 or 3 slopes of $1m{\times}1m$ area that represent each of 3 investigation sites. The possibility of wedge and toppling failure is very high in all 3 areas by using square-inventory method. Although possibility of plane failure is weak in the investigation site 2, the plane failures are frequently found from the slope of site 2. The bedding (or schistosity) plane and cleavage, another types of discontinuity coexist in meta-sedimentary rocks uulike igneous rocks, and therefore are important factors to be considered together with joint structures in th ε analysis of slope stability.

• Geomechanics and Engineering
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• v.36 no.6
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• pp.631-640
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• 2024

In the traditional slope stability analysis, ignoring the spatial variability of slope soil will lead to inaccurate analysis. In this paper, the K-L series expansion method is adopted to simulate random field of soil strength parameters. Based on Random Limit Equilibrium Method (RLEM), the influence of variation coefficient and fluctuation range on reliability of soil slope supported by micro-pile is investigated. The results show that the fluctuation ranges and the variation coefficients significantly influence the failure probability of soil slope supported by micro-pile. With the increase of fluctuation range of soil strength parameters, the mean safety factor of the slope increases slightly. The failure probability of the soil slope increases with the increase of fluctuation range when the mean safety factor of the slope is greater than 1. The failure probability of the slope increases by nearly 8.5% when the fluctuation range is increased from δ_v=2 m to δ_v =8 m. With the increase of the variation coefficient of soil strength parameters, the mean safety factor of the slope decreases slightly, and the probability of failure of soil slope increases accordingly. The failure probability of the slope increases by nearly 31% when the variation coefficient increases from COV_c=0.2, COV_φ=0.05 to COV_c=0.5, COV_φ=0.2.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1369-1375
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• 2006

This study analyzes stability and the reason of slope failure about cut slope on stony mountain in Acheondong, Guri and suggests the reasonal reinforce method. Based on the results of the subsurface exploration, laboratory tests, and the numerical analysis of finite element method, the potentials of plane and wedge failure are highly estimated. The safety factor was 1.2 under dry and 1.06 wet condition. The most proper reinforce method to raise the safety factor more than 1.5 was the way to control displacement by using step retaining wall, earth anchor, wire mesh, and rock anchor.

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.23-32
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• 2015

This paper addresses the effects of extreme rainfall on the stability of cut slopes in Yen Bai city, Northern Viet Nam. In this area, natural slopes are excavated to create places for infrastructures and buildings. Cut slopes are usually made without proper site investigations; the design is mostly based on experience. In recent years, many slope failures have occurred along these cuts especially in rainy seasons, resulting in properties damaged and loss of lives. To explain the reason that slope failure often happens during rainy seasons, this research analyzed the influence of extreme rainfalls, initial ground conditions, and soil permeability on the changes of pore water pressure within the typical slope, thereafter determining the impact of these changes on the slope stability factor of safety. The extreme rainfalls were selected based on all of the rainfalls triggering landslide events that have occurred over the period from 1960 to 2009. The factor of safety (FS) was calculated using Bishop's simplified method. The results show that when the maximum infiltration capacity of the slope top soil is less than the rainfall intensity, slope failures may occur 14 hours after the rain starts. And when this happens, the rainfall duration is the deciding factor that affects the slope FS values. In short, cut slopes in Yen Bai may be stable in normal conditions after the excavation, but under the influence of tropical rain storms, their stability is always questionable.

• Tunnel and Underground Space
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• v.30 no.1
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• pp.98-107
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• 2020

In surface mining, it is very important to create a mining area for economical mining. This study examined the contribution of design factors on slope stability with different slope design and blasting conditions. The design factors were the properties of the rock, the slope angle and the bench height, and the blasting conditions were reflected at different explosive weight and distances. The safety factor of slope was calculated by shear strength reduction method through 3D modeling, and the contribution rate of rock slope was 94.8%, which is relatively higher than other design factors, slope angle 0.89%, bench height 0.58%, and blasting It is shown that it affects about 3.73%, and it can be seen that blasting at a close distance can affect the stability of the slope.

• Journal of the Korean Geotechnical Society
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• v.25 no.2
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• pp.25-35
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• 2009

Slope failures are one of the significant disasters which causes lots of human casualties and huge financial losses every year. Previous researches on the slope failure have indicated that most accidents are closely related to the pore water pressure in the slope due to rainfall during the rainy seasons or stormy weather conditions. It would be therefore appropriate to consider the effect of pore water pressure in the design of slopes. As the existing slopes are generally reinforced by plants and other slope protecting measures, their boundary conditions are highly complicated. In this paper an attempt to develop a new modeling and analysis technique of slopes is proposed by including pore water pressure and adopting the coupled finite element method. Non-reinforced and reinforced slope models are considered. Representative analysis showed that the numerical modeling considering pore water pressure is appropriate in slope stability analysis. Flow behavior in the slopes is identified for various hydraulic boundary conditions. It is also shown that the effect of pore water pressure on slope stability is significant.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.73-80
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• 2010

Conventional slope stability analysis is focused on calculating minimum factor of safety or maximum probability of failure. To minimize inherent uncertainty of soil properties and analytical model and to reflect various analytical models and its failure shape in slope stability analysis, slope stability analysis method considering simultaneous failure probability for multi failure mode was proposed. Linear programming recently introduced in system reliability analysis was used for calculation of simultaneous failure probability. System reliability analysis for various analytical models could be executed by this method. Optimum design to determine angle of a simple slope is executed for multi failure mode using linear programming. Because of complex consideration for various failure shapes and modes, it is possible to secure advanced safety by using simultaneous failure probability.

• Geomechanics and Engineering
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• v.6 no.6
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• pp.545-560
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• 2014

For slope stability analysis, an alternative to the classical limit equilibrium method (LEM) of slices is the shear strength reduction method (SRM), which can be integrated into finite element analysis or finite difference analysis. Recently, probabilistic analysis of earth slopes has been very attractive because it is capable to take the soil uncertainty into account. However, the SRM is less commonly extended to probabilistic framework compared to a variety of probabilistic LEM analysis of earth slopes. To overcome some limitations that hinder the development of probabilistic SRM stability analysis, a new procedure based on recursive algorithm FORM with sensitivity analysis in the space of original variables is proposed. It can be used to deal with correlated non-normal variables subjected to implicit limit state surface. Using the proposed approach, a probabilistic finite element analysis of the stability of an existing earth dam is carried out in this paper.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.992-1006
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• 2008

The tunnel type spillways is under construction to increasing water reservoir capacity in Dae-am dam. Cutting-slope adjacent to outlet of spillways had been originally designed to be 63 degrees and about 65m in height. Examination is carried out in preceding construction that it is caused to some problems possibility which of machine for slope cutting couldn't approach to the site, blasting for cutting slope might have negative influence on highway and roads nearby, and fine view along the Tae-hwa river would be eliminated. In order to establish stability of tunnel and more friendly natural environment that we are carry out detailed geological surface survey and analysis of slope stability. So, we are design and construct for tunnel excavation with possible method that it is keep up natural slope. The result of survey and analysis that natural slope was divided 3 zone(A, B, C zone). In A and B zone, in first removed floating rock, high tensile tension net is install that it prevent of release and falling of rock, in order to security during under working. In addition to, pre-stressed rock anchor is install purpose of security during tunnel excavation because of fault zone near vertical developed above excavation level. Zone C is relatively good condition of ground, design is only carry out random rock bolt. All zone are designed and constructed drainage hole for groundwater and surface water is easily drain. Desinged slpoe is harmony with near natural environment. Successfully, construction is completed.

• Geotechnical Engineering
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• v.3 no.4
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• pp.21-30
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• 1987

The purpose of this paper is to develop a method of slope stability analysis, using slice method The direction of interstice forces was assumed in two ways: 1) inclined interslice force parallel to the base of slice, 2) normal interslice force normal to the boundary surface of slice being used in the existing slice method. The deviation from the value of interstice force caused by assumption was removed in the Processing of analysis, and the factor of safety was obtained more accurately by deciding the location of interstice force acting on each slice. More rational validity of the method with inclined interslice force was proved by performing slope stability analyses with both methods. The factor of safety obtained by the proposed method was compared with that by the existing methods, and the influence of seismic coefficient was also analyzed.