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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 6, Issue 4 - Dec 1996
Volume 6, Issue 3 - Sep 1996
Volume 6, Issue 2 - Jun 1996
Volume 6, Issue 1 - Mar 1996
Selecting the target year
The Effect of the Thermal Stress on the Mechanical Behaviour and Permeability of Rocks -1.mechanical Bechviour
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 1~9
Pocheon granite specimens were thermally treated with cycles of predetermined temperatures ranging 2
. Characterization of thermally-induced microcracks were carried out using optical microscopy and their effect on the various physical & mechanical properties were studied. Generally. uniaxial compressive strength, Young's modulus, Poisson's ratio, elastic wave velocity and specific gravity were found to decrease with increasing temperature. From 30
upwards, negative lateral strains were observed, which resulted in negative Poisson's ratio. Dynamic Young's modulus and Poisson's ratio were found to be generally most sensitive indicators to thermal cracking.
Deformation Behavoirs of Arched Openings Related with Roof Curvature
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 10~18
Arched openings are generally excavated in underground construction works. Since stress distribution around openings depends on geological structure in rock mass, any shape of arched openings fully conformed with in-situ stress condition should be recommended to maintain mechanical safety of structures. Shape of arched openings is specified by both roof curvature and height-width ratio, and especially this report presents deformation behaviors related with roof curvature. Scale model tests and numerical studies of various shaped openings are conducted, where rectangular opening shows the greatest convergence. Through the anlayses of various arched opengings, as radius of roof curvature is increased, roof lowering and sidewall closure are remarkably increased, whereas floor heaving is increased little by little. By the way, it is useful that displacements of openings are roughly estimated in the stage of preliminary investigation. To find out elastic displacements of arched openings with any roof curvature, regressional formula and charts by least square method are represented. In addition elastoplastic deformation behavoirs of arched openings concerning associated adn non-associated flow rule are discussed.
Developement of back-analysis model for determining the mechanical properties of jointed rock
Cho, Tae-Chin ;
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 19~29
Back analysis model, capable of calculating the mechanical properties and the in-situ stresses of jointed rock mass, was developed based on the inverse method using a continuum theory. Constitutive equation for the behavior of jointed rock contains two unknown parameters, elastic modulus of intact rock and stiffness of joint, hence algorithm which determines both parameters simultaneously cannot be established. To avoid algebraic difficulties elastic modulus of intact rock was assumed to be known, since the representative value of which would be quite easily determined. Then, the ratio (
) of joint stiffness to elastic modulus of intact rock was assigned and back analysis for the behavior of jointed rock was carried-out. The value
was repeatedly modified until the elastic modulus from back analysis became very comparable to the predetermined value. The joint stiffness could be calculated by multipling the ratio
to the final result of elastic modulus. Accuracy and reliability of back analysis procedure was successfully testified using a sample model simulating the underground opening in the jointed rock mass. Applicability of back analysis model for the underground excavation in practice was also verified by analyzing the mechanical properties of jointed rock in which underground oil storage cavern were under construction.
Groundwaterflow analysis of discontinuous rock mass with probabilistic approach
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 30~38
A two dimensional analysis program for groundwater flow in fractured network was developed to analyze the influence of discontinuity characteristics on groundwater flow. This program involves the generation of discontinuities and also connectivity analysis. The discontinuities were generated by the probabilistic density function(P.D.F.) reflecting the characteristics of discontinuities. And the fracture network model was completed through the connectivity analysis. This program also involves the analysis of groundwater flow through the discontinuity network. The result of numerical experiment shows that the equivalent hydraulic conductivity increased and became closer to isotropic as the density and trace length increased. And hydraulic head decreased along the fracture zone because of much water-flow. The grouting increased the groundwater head around cavern. An analysis of groundwater flow through discontinuity network was performed around underground oil storage cavern which is now under construction. The probabilistic density functions(P.D.F) were obtained from the investigation of the discontinuity trace map. When the anisotropic hydraulic conductivity is used, the flow rate into the cavern was below the acceptable value to maintain the hydraulic containment. But when the isotropic hydraulic conductivity is used, the flow rate was above the acceptable value.
The Comparison of the Ground Vibration Velocity by Dynamite and Finecker Blasting
Kim, Il-Jung ;
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 39~47
The results of the regression analysis and comparative study between 120 vibration events by dynamite blasting and 68 vibration events by finecker blasting which were monitored in the test blasting are as follows: The ground vibration velocity of dynamite blasting of 0.12 kg charge weight per delay at 7.4 m above the explosive is higher than that of finecker blasting of 0.96 kg charge weight per delay. In the case of 0.12 kg charge weight per delay, the ground vibration velocity of finecker blasting is equal to 5.5% of that of dynamite blasting at the 10 m distance from explosive. The decrement of ground vibration velocity of dynamite blasting of above 0.12 kg charge weight per delay is larger than that of finecker blasting of below 0.96 kg charge weight per delay. The rate of ground vibration velocity of the finecker blasting to that of dynamite blasting decreases with the distance from explosives, but increases with the decrease of charge weight per delay. The increment of ground vibration velocity of finecker blasting is less than that of dynamite blasting with the increase of charge weight per delay at the same distance from explosives. Under the condition of the constant critical ground vibration velocity or use the same charge weight per delay, the blasting working by finecker rather than by dynamite is able to be performed at the nearer place to structures.
Study on Characteristics of Diesel Particualte Matter and it's Measurement and Evaluation
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 48~56
Presently, mobile diesel equipments contribute a lot to improve the economic feasibility of underground mining and tunneling operations. Even in Korea, a lot of diesel equipments are being applied to the undergroud workings already, but the technology of management and control of them is not sufficient yet. This study handled the production procedure, characteristics and evaluation technology on diesel particulate matte(DPM) which is known as a carcinogen. For easy measurement of DPM using laser dust monitor, conversion known as a carcinogen. For easy measurement of DPM using laser dust monitor, conversion factor(k) to gravimetric concentration has been acquired. It is appeared that the critical material among the diesel exhaust pollutants is becoming DPM instead of NOx from this year of 1996 according to the Government regulation.
Simulation Modelling of the Pollutant Concentration in Vehicle Tunnels
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 57~63
The goal of this study is to develop a simulation model of the pollutant dispersion in vehicle tunnels, which can be utilized to optimize the tunnel ventilation system. Contaminant dispersion is modelled using a FDM solution of advective diffusion equation. Taking into consideration the local vehicle emission rates by year, it is user-oriented and its logic is generalized. Therefore, differences in the ventilation scheme can be easily adapted. The results of its application to a urban tunnel show that the relative errors are 1.1~6.8% for the natural velocity, 1.3% for the traffic-induced velocity and 2.9% for the total air quantity. Simulated CO concentrations along the entire tunnel show about 13% of the relative error.
Analysis of Fluid Flow around Ventilation Ducts inside a Vehicle Tunnel
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 64~68
Analyzed in this paper is fluid flow in the region near the exhaust and blower ports of the ventilation ducts inside a vehicle tunnel. Theoretical analysis shows that prediction of the energy loss in this region is important for designing the ventilation system. A finite-difference numerical model for the two-dimensional turbulent flow field was used to obtain the flow solution as well as the energy loss. It was shown that the blower-nozzle angle (
) had an important role in establishing both the pressure gradient and the energy loss, while the effect of the distance between two ports on them was not so significant.
A Study on Thermomechanical Failure Behavior of Granites for Radioactive Waste Repository
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 69~74
High temperature confined compressive tests for thermomechanical failure criteria were carried out for Iksan and Whandeung granites. Authors suggested new polynomial type failure coefficient functions by which conventional Hoek-Brown failure criteria was extended to thermomechanical one. Obtained results are as follow; 1) Failure coefficients, m and s of Hoek and Brown's empirical failure criteria were decreased as temperature increased. 2) Theoretically calculated values by suggested equations and experimented ones by confined compressive test were well coincided.
NATM 개념의 오류에 관한 고찰
Kalman Kovari ;
Tunnel and Underground Space, volume 6, issue 1, 1996, Pages 75~87