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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 7, Issue 4 - Dec 1997
Volume 7, Issue 3 - Sep 1997
Volume 7, Issue 2 - Jun 1997
Volume 7, Issue 1 - Mar 1997
Selecting the target year
Analysis of Energy and Ground Vibration of Plasma Blasting
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 267~273
Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method in controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmnetal impacts. The fragmentation energy level is evaluated by numerical simulation using PFC-2D for various drill hole pattern and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2~3 ㎥ granite boulder or 1.5 m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that the control of the blasting operations can be performed more precisely and safely.
Non-Destructive Test for Tunnel Lining Using Ground Penetrating Radar
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 274~283
It is necessary to estimate the soundness of tunnel using non-destructive tests(NDT) for effective repairs and maintenances. But, the state of tunnel lining could not be investigated using previous non-destructive techniques, due to the various types of support and accessibility only from one side in tunnel lining. Recently, the various non-destructive techniques such as ground penetrating radar(GPR) have been researched and developed for inspection of tunnel lining. In this study, the usefulness and applicability of GPR test in tunnel lining inspection has been investigated through model tests and tunnel site application. This paper described the tunnel lining inspection for lining thickness, cavity and support using GPR test. From the results of tests, we have concluded that GPR test are very useful and effective techniques to look into the interior of lining and measure the lining thickness.
Study on the Engineering Geological Characteristics Related to the Tensile Failure of Rock
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 284~292
An Effective Pressure Law for the Transport Property of Granite
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 293~298
Permeability was not represented as a simple function of the difference between confining pressure(
) and pore pressure(
). The effective pressure(
) for measurements of the permeability is shown to be
is a coefficient of effective pressure. Local values of
were determined at intervals along the pressure path which range 25MPa to 55MPa. The values of
ranged 0.65 to 1.09 for Pocheon granite and 1.20 to 1.43 for Wonju granite. Also, the value of
calculated by the cross-plotting method was 0.90 for Pocheon granite, 1.59 for Wonju granite and 4.35 for jointed Pocheon granite.
was found to be stress-history dependent.
A Study on the Ground Movement around Tunnel Reinforced by Umbralla Arch Method
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 299~309
Soil and rock improvement and reinforcement techniques are applied to achieve safe tunnel excavation in difficult geological conditions. The Umbrella Arch Method(UAM), one of the auxiliary techniques, is used to reduce ground permeability and improve stabtility of the tunnel by inserting a series of steel pipes into ground around the crown inclined to the longitudinal axis of the tunnel. Additionally, multi-step grouting is added through the steel pipes. UAM combines the advantages of a modern forepoling system with the grouting injection method. This technique has been applied in subway, road and utility tunneling sites for the last few years in Korea. This paper presents the results of analysis of the case studies on ground movements associated with UAM used in the Seoul Subway line 5 constructon site. Improvement of tunnel stability and decrease of ground settlement expected with pipe insertion are also discussed. Finally, the method to minimize ground settlements caused by NATM tunnelling are suggested.
Vibration Regulations and Damages Evaluation Method for Human
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 310~322
New limits of comfort boundary, psychological damage boundary and exposure limit for building residents by continuous and vibration are suggested. These limits are derived from the ISO 2631 and DIN 4150 regulations. A reasonable method to evaluate damages by vibrations is also suggested using the "total over-exposure of vibration" concept.; concept.
Characteristics of in situ stress regime measured by hydraulic fracturing technique and its application on tunnel design
Choi, Sung-Oong ;
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 323~333
A rock mass is usually classified by the results of geological survey and laboratory tests on rock specimens in order to obtain the adequate properties for the numerical analysis. For these purposes a rock mass strength is estimated based on the empirical criterion proposed by Hoek and Brown and a modulus of deformation is taken with the empirical relations developed by Bieniawski, Serafim and Pereira. In addition, the
value which is the ratio of the horizontal stress to the vertical stress is one of the most important input data in the numerical analysis. Its role on a tunnel stability analysis could be verified with the numerical results taken by a finite difference code or a distinct element code. However, a deduced value used to be applied for the
value in most of tunnel designs, even though the patterns of stress tensor are variable with regions and depths. Thus in situ stresses were measured by a hydraulic fracturing technique on several tunnel sites and applied directly to the tunnel design for the enhancement of its precision. With those informations on in situ stresses, the safe design should be obtained economically on the road or subway tunnels.
Numerical Resistivity Modeling Using Alpha Center Theory: A Case History for Field Resistivity Data
Tunnel and Underground Space, volume 7, issue 4, 1997, Pages 334~340
Alpha center theory which was first proposed by Stefanescu has been proved to be effective for the detection of the location of the conductive orebody. A numerical forward modeling was conducted to verify the effectiveness of this method. Field works were carried out along the three profiles in two different areas for the purpose of finding fractured zone which might be accompanied with the presence of the groundwater. And the results were modeled by alpha center method, which was later testified by wellproven 2-dimensional finite difference inversion scheme. Field data could be successfully modeled with this alpha center algorithm, especially for the smooth-varying resistivity models. For the abrupt change of the resistivity values, the alpha center coefficients have a tendency to be negative to simulate the steep resistivity gradients. This method is quite simple and easy for the future applications. The numerical calculation can be performed very quickly with the personal computers.