• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1782-1788
• /
• 2007

This study analyzed ground settlement and ground stress depending on tunnel excavation and the ground reinforcing grouting methods for double line road tunnel through deep weathered zone. Diameter of double line road tunnel was approximately 12m and umbrella arch method and side wall reinforcing grouting were applied. The ring-cut split excavation method and CD-cut excavation method for excavation method were applied. Analysis of failure rate and vertical stress ratio show that the tunnel for which the height of the cover(H) was higher than four times the diameter, it can be considered a deep tunnel. Comparisons of various excavation and ground reinforcement methods were showed that CD-cut method results in lower surface and crown settlement, and lower failure rate than where using Ring-cut split method. In addition the side wall reinforcing grouting resulted in reduction of tunnel displacement and settlement.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.8
• /
• pp.87-95
• /
• 2007

This study analyzed ground settlement and ground stress depending on tunnel excavation and the ground reinforcing grouting methods for double line road tunnel through deep weathered zone. Diameter of double line road tunnel was approximately 12m and umbrella arch method and side wall reinforcing grouting were applied. The ring-cut split excavation method and CD-cut excavation method for excavation method were applied. Analyses of failure rate and vertical stress ratio show that the tunnel for which the height of the cover (H) was higher than four times the diameter, can be considered a deep tunnel. Comparisons of various excavation and ground reinforcement methods showed that CD-cut method results in lower surface and crown settlement, and lower failure rate than that obtained by Ring-cut split method. In addition, the side wall reinforcing grouting resulted in reduction of tunnel displacement and settlement.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.5
• /
• pp.197-203
• /
• 2012

This paper studies network recovery method using logical multiple ring architecture embedded in WDM optical Internet environment. The multiple ring-based recovery method provides fast and simple network restoration operation, and performs local recovery that is detouring the failed link. The multiple ring architecture can provide higher resource efficiency by sharing the backup routes and reducing the number of spare wavelengths. This paper calculates the required spare capacity ratio using Cut-Sets in the given network topology and performs simulation for comparative analysis.

• Geotechnical Engineering
• /
• v.14 no.5
• /
• pp.5-16
• /
• 1998

2-D numerical methods have been applied to analyze the stability of tunnels because of computation efficiency, though the ground around the tunnel under construction shows 3-D reformational behaviour due to the transverse and longitudinal arching effects. Load distribution factors are introduced to the 2-D analysis for the consideration of the effects of the tunnel advance in three dimensions. The load distribution factors influence significantly the ground deformation and the load of primary supports like shotcrete and rockbolts. According to the previous studies for 3-D numerical studies. it was shown that load distribution factors were heavily dependent on the ground deformational properties, tunnel size and the advance length of a tunnel. However, as the quantitative methods evaluating the factors have not been presented yet, constant values have been assigned to the factors for 2-D analysis even if the conditions for tunnel design are different. Accordingly, this paper presents the method to evaluate quantitatively the load distribution factors through the regression analysis of 3-D analysis data on 72 design cases. Also, new modification to the load distribution factors are suggested for the ring-cut excavation method because the conventional 2-D analysis is not able to consider the support effects of the core left on the tunnel face.

• Journal of architectural history
• /
• v.12 no.3
• /
• pp.53-63
• /
• 2003

Tree-ring chronologies can be used to date historical buildings by matching them with the chronologies of living trees or previously dated samples. Tree-ring dating gives a calendar year to each tree ring and produces the felling dates of logs or woods which had been used for buildings. In Korea, several chronologies of Japanese red pine(Pinus densiflora Sieb. et Zucc., 'sonamu' in Korean), a major species for the wooden building materials, have been developed and used for dating historical buildings. In this study, Tongmyungjeon Hall of Changkyung Palace in Seoul was dated by tree rings. The present Tongmyungjeon Hall was known to be reconstructed in A.D. 1834 after burned-out in A.D. 1790. We sampled total of 122 wood samples which were replaced during the repair process in 2002-2003. Felling dates of the samples were determined by the dendrochronological crossdating method. Crossdating method employs graphic comparison of the master patterns (ring-width chronologies of known dates) with those of the sample chronologies of unknown dates. Tree-ring dates confirmed that the reconstruction of 1834 utilized second-handed timbers as well as fresh-cut ones. The felling dates of wooden floor frames were mostly A.D. 1913, indicating the 'Ondol' floors were changed to the wooden floors around 1914 when the Japanese rulers brutally destroyed the royal Korean Palaces and transformed palace buildings to their offices or exhibition halls after occupying Korea in 1910. This study proved that tree-ring dating was a useful and accurate method to identify the critical dates for the history of Korean traditional buildings.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.20 no.1
• /
• pp.183-195
• /
• 2018

Recently, the need for research on vertical shaft excavation is increasing with the increase of the demands for the underground and utility tunnels. As a part of the R&D project of the Ministry of Land, Infrastructure and Transport, CUT (center for utility tunnel) has developed "Ring cut method". "Ring cut method" is a method to improve the stability of the ground against the basal heave by excavator wall pre-penetration during vertical shaft excavation. In this study, the basal heave was simulated by centrifugal model test. The basal heave, ground subsidence, and ground deformation of surrounding ground were analyzed by soil plug effect from wall pre-penetration. It was found that the soil plug could control the basal heaving and ground subsidence, and verified that the 'Ring cut method' could be a good countermeasure for the ground stability against the basal heave.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.14 no.6
• /
• pp.262-266
• /
• 2004

Rutile single crystals were grown by the skull melting method. Ti metal ring was used for initial RF induction heating. The grown crystals were cut into wafer of 5.5 mm diameter and 1mm thickness. The wafers were annealed in air at $1300^{\circ}C$ up to 15 hours and their transmittance spectra $(\lambda= 200~25000 nm)$ were obtained.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.5 no.3
• /
• pp.225-231
• /
• 2001

When building tunnels beneath riverbeds where very large quantities of groundwater inflow exist, added to high water head the soil supporting conditions are very poor because the soil consists of sand and silt, etc. It is necessary to have grouting and mini pipe roof installed in the region for ground reinforcement to decrease permeability. According to this result of horizontal boring and laboratory soil testing, ground reinforcement was achieved by L.W grouting for range of 3.0 times the tunnel radius, to increase stability of the tunnel we used the ling-cut method, 0.8m for one step excavation, shotcrete with 25cm thick, steel lib with H-$125{\times}125$. and a temporary shotcrete invert 20cm thick was installed to prevent deformation of the tunnel.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.613-617
• /
• 2001

The test items like as endurance, air leakage and oil endurance test is requested for reliability evaluation about O-ring which is a kind of core machinery accessories of semi-conduct manufacturing equipment. For verification of these, we design and manufactured a test system for endurance, air leakage and oil endurance of O-ring for semi-conduct manufacturing equipment, and also performed the test for two kinds of O-ring, as it were Viton and Kalretz. The characteristics of this test equipment consist in realization of the test conditions of semi-conduct manufacturing equipment and satisfying the test method. The test conditions are cut gas, vacuum grade, temperature and revolution numbers in the endurance test system, vacuum grade and temperature in the air leakage test system, temperature and time in the oil endurance test system. The separating test results for wearing which is an oil endurance test item, the wearing index of domestic produced Viton O-ring is higher than foreign product by 2%, wearing rate of Kalretz O-ring better than Viton O-ring by 17%, and particles existed in various place. The test result of air leakage which is measured through the RGA sensor used Helium, the vacuum grade was $10^-3$Torr. And the test result of oil endurance, the volume change rate was 7~15%. Hereafter, we intend to analysis the reliability test evaluation and to utilize for domestic manufacturing companies by establishing data base and developing reliability softwares.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.941-946
• /
• 2008

D&B method in tunnel construction requires accurate and rapid measurement of the ground movement, which of essential for feedback analysis. Recently, survey technique adapting IT is getting more and more emphasized in the field of construction and tunnel survey also follow the same trend. Case study and adaptability of IT technique for tunnel survey will be discussed in this study. The application of laserscannig method in the field of tunnel construction was reported in several advanced country including Austria and Japan. Survey for the crown and shoulder movements by IT survey method was conducted and the results were compared to those do the conventional method. The pipe-roof, grouting, ring-cut are installed in the this site to prevent expected large ground settlement. The result show that laserscanner system is prefered rather than conventional method in that better understanding for the displacement condition and origin condition was liable by the lasersacnnig method. IT survey solution makes if possible to execute more economic and safe construction.