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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Tunnel and Underground Space
Journal Basic Information
Journal DOI :
Korean Society for Rock Mechanics
Editor in Chief :
Volume & Issues
Volume 16, Issue 6 - Dec 2006
Volume 16, Issue 5 - Oct 2006
Volume 16, Issue 4 - Aug 2006
Volume 16, Issue 3 - Jun 2006
Volume 16, Issue 2 - Apr 2006
Volume 16, Issue 1 - Feb 2006
Selecting the target year
A Case Study on Evaluation of Engineering properties for Block-in-matrix Rocks
Lee Sung-Ki ; Hwang Nak-Yeon ; Kim Sung-In ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 102~108
Weathering Sensitivity Characterization for Rock Slope, Considering Time Dependent Strength Changes
Lee Jeong-Sang ; Bae Seong-Ho ; Yu Yeong-Il ; Oh Joung-Bae ; Lee Du-Hwa ; Park Joon-Young ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 109~134
Rocks undergo weathering processes influenced by changing in pressure-temperature condition, atmosphere, underground water, and rainfall. The weathering processes change physical and chemical characteristics of the rocks. Once the rocks are weathered, the characteristics of them are changed and, because of the changing, several disadvantages such as rock slope failures and underground water spouts are can occur. Before we cut a large rock slope, therefore, we must analyze current weathering conditions of rocks and predict weathering processes in the future. Through the results of such analyses, we can judge reinforcement works. In order to comply with such requests, chemical weathering sensitivity analysis which was analyzed from chemical weathering velocities and other characteristics of rocks has been applied in several prior construction works in Korea. But, It is defective to use directly in engineering fields because it was developed for soils(not rocks), it has too mny factors must be considered and the relationships between the factors are not clear, and it is hard to explain the weathering processes in engineering time range. Besides above, because it has been used for isotropic rocks, this method is hard to apply to anisotropic rocks such as sedimentary rocks. Acceding to studies from morphologists (e.g. Oguchi et al., 1994; Sunamura, 1996; Norwick and Dexter, 2002), time dependent strength reduction influenced by weathering shows a negative exponential function form. Appling this relation, one can synthesize the factors which influence the weathering processes to the strength reduction, and get meaningful estimates in engineering viewpoint. We suggest this weathering sensitivity characterization method as a technique that can explain time dependent weathering sensitivity characteristics through strength changes and can directly applied the rock slope design.
Estimation of Rock Mass rating(RMR) and Assessment of its Uncertainty using Conditional Simulations
Hong Chang-Woo ; Jeon Seok-Won ; Koo Chung-Mo ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 135~145
In this study, conditional simulation was conducted to estimate rock mass rating(RMR) in unsurveyed regions. Sequential Gaussian simulation(SGS) and sequential indicator simulation(SIS) were applied for estimating RMR from the bore hole logging data. The uncertainty of SGS and SIS was verified by sample cross validation. A subset composed of 5 bore hole logging data among the original 30 bore hole logging data was set aside as test data. The remainder was training data. The quality of SGS and SIS estimation on the testing data reflects how well it would perform in an unsupervised setting. SGS and SIS were useful stochastic methods to estimate the spatial distribution of rock mass classes correctly and assess the uncertainty of estimation quantitatively. The result of conditional simulation can offer useful information of rock mass classes such as RMR in unsurveyed regions.
A Case Study about the Slope Collapse and Reinforcement Method on the Infinite Slope
You Byung-Ok ; Hong Jung-Pyo ; Jun Jong-Hern ; Lee Tae-Sun ; Min Kyoung-Nam ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 146~155
The target slope of this study, formed during the construction of highway, is the very high infinite slope where sliding began along the discontinuity. Although an attempt was made to stabilize the upper part of the slope by installing the rock anchors, large scale failure was occurred at the lower part if the reinforced area. Afterwards, subsequent failures were observed two times. To investigate the cause of the failure, residual shear strength was measured by performing the direct shear test of rock specimen of the site. The anchor design was based on the pull-out test. Considering the slope surface where the undulation was severe and the variation of strength was very large, buttressing was used to obtain the required anchoring capacity.
A Case Study of Air Deck Blasting Method
Lee Shin ; Kim Sang-Wook ; Kang Dea-Woo ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 156~165
Already, vari-stem, gas-bag, power deck, air ball etc. are used by various blasting methods to take the advantage of air decking technology in abroad. Air tube product has been used continuously in domestic and air ball product was made recently. In the case study, we analyzed about the application and the effect or air deck blasting method in domestic blasting area. As results or this case study, it was shown that blasting vibration was decreased about
and quantities or explosives was decreased about
. Also, in the case of using air deck blasting method, fragmentation was shown to be smaller than common blasting method.
Dynamic Frictional Behavior of Artificial Rough Rock Joints under Dynamic Loading
Jeon Seok-Won ; Park Byung-Ki ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 166~178
Recently, the frequency of occurring dynamic events such as earthquakes, explosives blasting and other types of vibration has been increasing. Besides, the chances of exposure for rock discontinuities to free faces get higher as the scale of rock mass structures become larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, artificially fractured rock joint specimens were prepared in order to examine the dynamic frictional behavior of rough rock joint. Roughness of each specimen was characterized by measuring surface topography using a laser profilometer and a series of shaking table tests was carried out. For mated joints, the static friction angle back-calculated ken the yield acceleration was
lower than the tilt angle on average. The averaged dynamic friction angle for unmated joints was
lower than the tilt angle. Displacement patterns of sliding block were classified into 4 types and proved to be related to the first order asperity of rock joint. The tilt angle and the static friction angle for mated joints seem to be correlated to micro average inclination angle which represents the second order asperity. The tilt angle and the dynamic friction angle for unmated Joints, however, have no correlation with roughness parameters. Friction angles obtained by shaking table test were lower than those by direct shear test.
Study of Blast Ground Vibration & Noise Measurements In-situ and Effect Analysis for Numerical Analysis, Rational Blasting Design at an Eel Farm
Lee Song ; Kim Sung-Ku ; Rhee Yong-Ho ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 179~188
The vibration or/and noise generated by blast operations might cause not only structural damage to properties but mentally also to humans and animals. For that reason, maximum permitted vibration and noise levels are set by sensitivities of structures and they are used for the management of blast vibration. It is known that the fish lived in water are more sensitive to vibration than land animals, and thus the adverse impact of the blasting on fish farms should be very concerned. This study investigated the vibration and noise levels at a large eel farm located some 840 meters of the blasting site through the large real-scale experiments of blastings, prior to conducting the actual blasting. As a result, it was found that the noise met the requirement to be within maximum permitted level, while the ground vibration exceeded the permitted vibration. Accordingly, the impact of the excess vibration was investigated by an existing empirical method and verified by a new three dimensional numerical analysis. In this study, such an inspection process was briefly described, and a method was suggested for the examination of possible adverse effects from blasting on vibration-sensitive structures like the eel farm. The study also introduced a design method that controls the blast effects - ground vibration and noise.
Validity of the Attenuation Equation of MOCT Guide Line for Surface Rock Blasting
Choi Mi-Jin ; Yang Hyung-Sik ;
Tunnel and Underground Space, volume 16, issue 2, 2006, Pages 189~193
Guide line for rock blasting design of the MOCT(Ministry of Construction and Transportation) adopts attenuation equation of du Pont company for blasting vibration. In this paper the validity of the equation is studied by comparing with several equations of Dowding, Devine and author's induced from the domestic vibration data. The equation is inadequately used and predicted values are proved to be underestimated and causes vibration problems.