• Geomechanics and Engineering
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• v.13 no.2
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• pp.237-254
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• 2017

Estimation of slope stability is a very important task in geotechnical engineering. However, its estimation using conventional and soft computing methods has several drawbacks. Use of conventional limit equilibrium methods for the evaluation of slope stability is very tedious and time consuming, while the use of soft computing approaches like Artificial Neural Networks and Fuzzy Logic are black box approaches. Multiple Regression (MR) analysis provides an alternative to conventional and soft computing methods, for the evaluation of slope stability. MR models provide a simplified equation, which can be used to calculate critical factor of safety of slopes without adopting any iterative procedure, thereby reducing the time and complexity involved in the evaluation of slope stability. In the present study, a multiple regression model has been developed and tested its accuracy in the estimation of slope stability using real field data. Here, two separate multiple regression models have been developed for dry and wet slopes. Further, the accuracy of these developed models have been compared and validated with respect to conventional limit equilibrium methods in terms of Mean Square Error (MSE) & Coefficient of determination ($R^2$). As the developed MR models here are not based on any region specific data and covers wide range of parametric variations, they can be directly applied to any real slopes.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1365-1371
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• 2008

Based on the data obtained from field investigation and soil testing to slope hazards occurrence section and non-occurrence section in gneiss area, a prediction technique was developed by the use of a decision tree model. The slope hazards data of Seoul and Kyonggi Province were 104 sections in gneiss area. The number of data applied in developing prediction model was 61 sections except a vacant value. The statistical analyses using the decision tree model were applied to the entrophy index. As the results of analyses, a slope angle, a degree of saturation and an elevation were selected as the classification standard. The prediction model of decision tree using entrophy index is most likely accurate. The classification standard of the selected prediction model is composed of the slope angle, the degree of saturation and the elevation from the first choice stage. The classification standard values of the slope angle, the degree of saturation and elevation are $17.9^{\circ}$, 52.1% and 320m, respectively.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.25-31
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• 2004

Rail road slope can be fatted because of existence of unexpected soft subsoil. Purpose of this study is verifying the cause of rail road slope failure and determination of soil strength for remedy. Drilling some boreholes, cone penetration test and field vane test were executed in order to find out the cause of slope failure. In addition, laboratory test was conducted in order to determine soil strength of soft soil sampled as undisturbed state. As a result of both the in-situ and the laboratory tests, the cause of slope failure is thought to be propagation of failure zone by progressive rupture of overconsolidated clay Soft soil strength was determined through back analysis of the failed slope.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11b
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• pp.155-180
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• 2000

The pattern of domestic slope construction has been steadily changed from the simpled and small-scale to the large-scale and complicated one, frequently near the existing structures, as the density of population and the traffic increases. In some cases, the slopes become steeper and larger due to the road improvement and construction. For the rock slope, the existence of discontinuity cannot be disregarded and acts as an important factor on the slope stability. Most of the existing methods for stabilizing the slope were focused on reducing the slope angle. Under the specific geographic condition, it is necessary to concentrate more efforts on the research and development of supporting system for the slope stability. As a supporting system, it is often very advantageous to use the FRP pipe grouting method that is similar to the existing soil nailing method or the rock bolting method but uses the high strength FRP pipe as a principal reinforcement in place of steel bar. Through the FRP pipe, the grout material can be injected into the rock mass to improve its shear strength to the required value. .In this study, the characteristics of FRP are investigated by the laboratory tests and the field tests. And, the practical aspects of FRP method are reviewed and analyzed.

• Tunnel and Underground Space
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• v.16 no.6 s.65
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• pp.451-466
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• 2006

Analysis of slope behavior concerning the structural characteristics of field rock mass can be processed by virtue of borehole information of joint orientation and position acquired from DOM drilled core. Anticipated sliding potential of pre-failed rock slope is analyzed and the regional slope instability is investigated by inspecting the hazardous joints and blocks the traces of which is projected on the cut-face. Cross section has been set at the center of rock slope and the traces of both joints and tetrahedral blocks, which potentially can induce the slope failure, are drawn to investigate the failure modes and the triggering mechanism. Automated monitoring system has been established to measure the slope movement and especially, inclinometer has been installed inside DOM borehole to analyze the slope movement by considering the internal rock structure. Algorithms for predicting the slope failure time have been reviewed and the significance of heavy rainfall on the slope behavior has been investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.229-240
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• 2006

Most of rock slopes contain a lot of discontinuities which have a specific direction and various characteristics. In general, the collapses of the rock slopes occur when the sliding dip of the discontinuity is higher than the internal friction angle and also smaller than the free-air plane of the slope. If a general slope theory is only considered in the case of field exploration of the slopes, there is a possibility that dangerous slopes might be estimated as stable slopes. We mention problems that can easily fail to notice something in field exploration and propose the alternatives to solve the problems through the case studies.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.303-315
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• 2001

This study is a research result of investigating causes of landslides occurred at Uijongbu in Kyonggi Province, Korea. For works of this research, informations and data about landslides occurred at the site, geological and topographical informations were collected to analyze causes of landslides, and mapping landslides was performed by using results of field investigation. Data about rainfall during occurrence of landslides around Uijongbu was also used to find the effect of intense rainfall on occurrence of landslides. Based on informations obtained from field investigation and collected data, the scale and the pattern of landslides were analyzed and influencing factors on landslide such as intensity and duration of rainfall, topography, geologic condition, geotechnical engineering properties of ground, forestry were investigated statistically to find causes of landslides. On the other hands, for geotechnical engineering respects, slope stability analysis was performed for the typical sites chosen from the sites where the landslides occurred, using informations obtained from detailed topographical survey with total stations, field reconnaissance and results from laboratory tests.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.189-199
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• 2006

This paper presents a field study of the stability of slope collapsed during road construction and proposes a reasonable countermeasure if the current slope is unstable. As a result of slope investigation, it was found that the slope includes five tension cracks and the sliding surface is started from the tension crack and propagated the surface soil layer through weathered rock layer. The slope stability analyses are conducted in case of dry and rainfall seasons. The results indicate that the slope is unstable status. A reinforcement method of slope failure should be selected according to the scale of failure. That is, the scale of slope failure, which is classified small, middle and large size determines the reinforcement method of slope. Since the slope interested in this study is large size failure slope, the reinforcement method to control slope failure is selected stabilizing piles, and seed spray and drainage of surface waterare also selected to remain the factor of safety. The SLOPILE (Ver. 3.0) program is applied in order to do stability analysis of slope reinforced by piles. As the result of analysis, the slope reinforced by a row of piles shows the stable state. It is clearly confirmed that the stabilizing of piles can improve the stability of slope.

• Tunnel and Underground Space
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• v.19 no.1
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• pp.31-42
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• 2009

One set of hardware system of guide point method (GP method), modified from the multistage convergent photographing technique, was developed to interpret the geometrical characteristics of Joints photogrammetrically on rock slope. Before the field application of the hardware system, the level of errors and constraints that ran be acceptable in the field measurement has been severely investigated in the laboratory and the optimum photographing scheme was analyzed. The range of the most suitable convergence angle between two cameras was $25^{\circ}{\sim}150^{\circ}$ and the photographing distance was about 5.5 m when using a 2 M pixel digital camera. An extended analyzing technique, which was newly developed in this study, was applied to the field measurement to magnify the benefits of GP method. This technique can be applied when survey for the wide range of rock surface is necessary. The global coordinates of ground control points for the neighbor photographing area ran be introduced without any preparation from the previous photographed area using this technique. It could reduce phographing time in the field.

• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.49-55
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• 2016

Field measurement units and a system were constructed and installed in a waste-dump slope at the Imgi mine to investigate and analyze the variations in the unsaturated characteristics of the soil. The field instrumentation system was composed of a data acquisition system (DAS), a solar system, and measuring sensors. The rainfall, matric suction, and volumetric water contents were continuously measured from the units in the instrumented site. The variations in matric suction and volumetric water content were primarily affected by the rainfall intensity. At the surface of the slope, the largest increase and decrease in the changes in matric suction and volumetric water content were observed during the wetting and drying processes, respectively. Also, the matric suction and volumetric water content were 5-35 kPa and 0.12-0.24, respectively. However, the ground water level was not suddenly increased just after rainfall but gradually increased after 2 or 3 days later.