• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.03a
• /
• pp.501-508
• /
• 2002

The percentage of a mountainous district in our country is comparatively high but the concern for rock mass has been disregarded for a long time. Especially for rock slope, the most important factors are geometric characteristics and their shear strength parameter. In this paper, parametric studies are performed using the distinct element computer program UDEC-BB for rock slopes. Parameters adopted in this paper are joint angle, spacing, persistence, aperture and shear strength parameters (JRC, JCS, basic friction angle). To estimate slope stability, shear strength reduction method is used. The most important factors affecting rock slope stability are joint angle and spacing. The relationship between average displacement calculated by UDEC-BB and safe factor by shear strength reduction method is researched.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.5 no.2
• /
• pp.209-216
• /
• 2003

The present with in this country, rock bolt installation, shotcrete, and concrete lining in construction order has become accepted as a general tunnelling method in NATM. On the other hand Unlined tunnelling method, which was developed by many countries near Scandinavian Peninsula with hard rocks comparatively, has recently been introduced all over the world, and numerous studies about that have been being devoted to domestic tunnels. Unlined tunnelling method has been developed on the basis of the permanently unsupported openings, and general 7 requirements for them were suggested by Nick Barton. There are no case record about these conditions for Q-system in this country. Therefore, input parameters for Q-system under these conditions were applied to general road tunnel cross-section and numerical analyses for each condition were executed with UDEC-BB, Distinct Element Method.

• Tunnel and Underground Space
• /
• v.9 no.2
• /
• pp.141-148
• /
• 1999

Distinct element simulation in jointed rock masses is largely dependent upon the joint constitutive equation used. This paper describes the differences between the Barton-Bandits (BB) and the Mohr-Coulomb (MC) joint constitutive models for the stability analysis of the jointed rock slopes. The BB model, which allows the modelling of the dilation accompanying shear, predicts results very similar to the present condition of slopes. Consequently the 10 cm thick shotcrete was proposed for the reinforcement of those slopes. The MC model, however, in which the dilation angle is constant, is relatively insensitive to the behaviors of joints.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1993.10b
• /
• pp.235-247
• /
• 1993

The 62 m span Olympic lee Hockey cavern in Gjovik, Norway, is located in jointed gneiss of average RaD = 70% and has a rock cover of only 25 to 50m, thus posing challenging design p problems. The investigations prior to construction included two types of stress measurements, cross-hole seismic tomography, special coe logging, Q-system classification and numerical modelling with UDEC-BB. Predicted maximum deformations were 4 to 8 mm; surprisingly small due to the high horizontal stresses recorded. Extensometer (MPBX) installations from the surface prior to construction, precision surface levelling and MPBX installed from inside the cavern give a combined measure of maximum deformations in the range 7 to 8 mm with the 62 m span fully e excavated, and three adjacent caverns for the Postal Services also completed.