• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.551-558
• /
• 2000

When cut slope is excavated, corestone in cut slope exists 20∼30%. In case of soil and soft rock mixing, people lay out gradient of 1 : 0.5, because of soft rock slope. In a case, slope that exists corestone between soil happens to large landslide. So, As a study performs geological survey, Analysis of slope stability reinforcement measures, etc, A study presents example meaures and analysis on slope stability of corestone.

• Journal of Korean Society of Steel Construction
• /
• v.21 no.6
• /
• pp.563-574
• /
• 2009

This paper briefly describes the fundamental strategies--path-tracing, pin-pointing, and path-switching--in the computational elastic bifurcation theory of geometrically non-linear single-load-parameter conservative elastic spatial structures. The stability points in the non-linear elasticity may be classified into limit points and bifurcation points. For the limit points, the path tracing scheme that successively computes the regular equilibrium points on the equilibrium path, and the pinpointing scheme that precisely locates the singular equilibrium points were sufficient for the computational stability analysis. For the bifurcation points, however, a specific procedure for path-switching was also necessary to detect the branching paths to be traced in the post-buckling region. After the introduction, a general theory of elastic stability based on the energy concept was given. Then path tracing, an indirect method of detecting multiple bifurcation points, and path switching strategies were described. Next, some numerical examples of bifurcation analysis were carried out for a trussed stardome, and a pin-supported plane circular arch was described. Finally, concluding remarks were given.

• Journal of the Korean Geotechnical Society
• /
• v.19 no.4
• /
• pp.65-74
• /
• 2003

This paper presents the results of a comparative study between FEM and LEM on slope stability analysis. For validation, factors of safety were compared between FEM and LEM. The results from the two methods were in good agreement. This suggests that the FEM with the shear strength reduction method can be effectively used on slope stability analyses. A series of analyses were then performed using the FEM for various constitutive laws, slope angles, flow rules, and the finite element discretizations. Among the findings, the finite element method in conjunction with the shear strength reduction method can provide reasonable results in terms of safety. Also revealed is that the results of FEM can be significantly affected by the way in which the type of constitutive law and flow nile we selected.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.434-443
• /
• 2009

Slope stability analysis is an essential part of rock slope design. For highly fractured rock, the limit equilibrium method (LEM) based slope stability analysis with a circular failure surface is often carried out assuming the rock mass behaves more or less as a continuum. This paper examines first, the applicability of the finite-element method (FEM) based shear strength reduction (SSR) technique for highly fractured rock slope, and second the use of Mohr-Coulomb (MC) failure criterion in conjunction with generalized Hoek-Brown (HB) failure criterion. The numerical results on a number of cases are compared in terms of the factor of safety (FS). The results indicated that the FEM-based SSR technique yields almost the same FSs from LEM, and that the MC and HB failure criteria yield almost identical FSs when the strength parameters for MC failure criterion are obtained based on the modified HB failure criterion if and only if value of the Hoek-Brown constant $m_i$ is smaller than 10 and slope angle is smaller than 1:1, otherwise MC failure criteria over-estimate the factor of safety.

• Tunnel and Underground Space
• /
• v.7 no.2
• /
• pp.150-157
• /
• 1997

Various analytical, empirical and theoretical methods for slope stability assessment were applied on slopes to develop aggregate quarry optimally. Among them are block theory, stereographic analysis, RMR, SMR, limit equilibrium method and maximum likelihood. Test site was estimated that slopes were apt to fail although rock quality was good. Modified direction and dip angle was suggested for stability. To reduce the overbreak and to improve the stability, the vertical blasting was recommended for new subground level.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1997.03a
• /
• pp.97-102
• /
• 1997

• Structural Engineering and Mechanics
• /
• v.20 no.3
• /
• pp.313-334
• /
• 2005

The paper presents a new approach for the analysis of slope stability that is based on the numerical solution of a differential equation, which describes the thrust force distribution within the potential sliding mass. It is based on the evaluation of the thrust force value at the endpoint of the slip line. A coupled approximation of the slip and thrust lines is applied. The model is based on subdivision of the sliding mass into slices that are normal to the slip line and the equilibrium differential equation is obtained as the slice width approaches zero. Opposed to common iterative limit equilibrium procedures the present method is straightforward and gives an estimate of slope stability at the value of the safety factor prescribed in advance by standard requirements. Considering the location of the thrust line within the soil mass above the trial slip line eliminates the possible development of a tensile thrust force in the stable and critical states of the slope. The location of the upper boundary point of the thrust line is determined by the equilibrium of the upper triangular slice. The method can be applied to any smooth shape of a slip line, i.e., to a slip line without break points. An approximation of the slip and thrust lines by quadratic parabolas is used in the numerical examples for a series of slopes.

• Economic and Environmental Geology
• /
• v.34 no.6
• /
• pp.601-615
• /
• 2001

The study area. Boeun-eup Boeun-kun, belongs to Ogchon metamorphic belt which is highly metamorphosed and consisted of complex geologic formations. Even though the geological structures and formations are complex and metamorphosed, the geological investigation and consideration are not enough and consequently the plane failure is occurred in the rock slope which was under construction on 1 : 0.5 gradient. This area is assessed as unstable and additional failure is possible by the discontinuity with same direction of failure surface. Therefore, the authors evaluate the slope stability using various analysis methods such as SMR, stereographic projection method, and the limit equilibrium analysis. In order to analyze stress redistribution and nonlinear displacement behavior caused by stress release, the authors conduct numerical analysis with UDEC and then the behavior of rock mass is analyzed after reinforcements are applied.

• Geomechanics and Engineering
• /
• v.24 no.5
• /
• pp.491-503
• /
• 2021

Shallow tunnels are vulnerable to earthquakes, and shallow ground is usually inhomogeneous. Based on the limit equilibrium method and variational principle, a solution for the seismic collapse mechanism of shallow tunnel in inhomogeneous ground is presented. And the finite difference method is employed to compare with the analytical solution. It shows that the analytical results are conservative when the horizontal and vertical stresses equal the static earth pressure and zero at vault section, respectively. The safety factor of shallow tunnel changes greatly during an earthquake. Hence, the cyclic loading characteristics should be considered to evaluate tunnel stability. And the curve sliding surface agrees with the numerical simulation and previous studies. To save time and ensure accuracy, the curve sliding surface with 2 undetermined constants is a good choice to analyze shallow tunnel stability. Parameter analysis demonstrates that the horizontal semiaxis, acceleration, ground cohesion and homogeneity affect tunnel stability greatly, and the horizontal semiaxis, vertical semiaxis, tunnel depth and ground homogeneity have obvious influence on tunnel sliding surface. It concludes that the most applicable approaches to enhance tunnel stability are reducing the horizontal semiaxis, strengthening cohesion and setting the tunnel into good ground.

• The Journal of Engineering Geology
• /
• v.24 no.4
• /
• pp.511-523
• /
• 2014

Limit equilibrium analysis and finite difference analysis were used to evaluate slope stability in the in Gohan, Korea, which is affected by large-scale tensile cracks and uplift. There is a thick colluvial layer in the study area and predicting ground behavior is problematic because the presence of clay makes it difficult to determine the strength parameters of the soil. Consequently, a numerical model able to reflect the collapse properties of the site was required that applied the modified boundary layer model and calculated the strength parameters using back analysis. The numerical simulation results that consider the strength parameter one does with the present situation the establishment of the pile is completed, and the simulation is able to asses ground stability in complex terrain in a reliable manner. Also the somewhat it judges with the fact that it will be able to provide the fundamental data which secures the stability of the segment where it is unstable.