• Nuclear Engineering and Technology
• /
• v.53 no.5
• /
• pp.1686-1704
• /
• 2021

This study addresses the numerical simulation of the shield building of an AP1000 nuclear power plant (NPP) subjected to a large commercial aircraft impact. First, a simplified finite element model (F.E. model) of the large commercial Boeing 737 MAX 8 aircraft is established. The F.E. model of the AP1000 shield building is constructed, which is a reasonably simplified reinforced concrete structure. The effectiveness of both F.E. models is verified by the classical Riera method and the impact test of a 1/7.5 scaled GE-J79 engine model. Then, based on the verified F.E. models, the entire impact process of the aircraft on the shield building is simulated by the missile-target interaction method (coupled method) and by the ANSYS/LS-DYNA software, which is at different initial impact velocities and impact heights. Finally, the laws and characteristics of the aircraft impact force, residual velocity, kinetic energy, concrete damage, axial reinforcement stress, and perforated size are analyzed in detail. The results show that all of them increase with the addition to the initial impact velocity. The first four are not very sensitive to the impact height. The engine impact mainly contributes to the peak impact force, and the peak impact force is six times higher than that in the first stage. With increasing initial impact velocity, the maximum aircraft impact force rises linearly. The range of the tension and pressure of the reinforcement axial stress changes with the impact height. The perforated size increases with increasing impact height. The radial perforation area is almost insensitive to the initial impact velocity and impact height. The research of this study can provide help for engineers in designing AP1000 shield buildings.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.10a
• /
• pp.591-600
• /
• 2005

There are many cross tunnelling methods such as NTR, TRCM, Messer Shield, Front Jacking, and Pipe Roof Method. The advantages of adopting RPS(roof panel shield) method in crossing tunnel construction with comparing other existing cross tunnelling method are needed a little space and easy to change the direction of cutting shoe during the construction of pipe roof. The numerical analysis of RPS was performed for the application in the crossing tunnel under railroad. The earth pressure distribution and settlement were predicted when the RPS method was applied during the excavation for crossing railroad tunnel construction.

• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.436-439
• /
• 2007

This paper describes the optimization of PGS(Patterned Ground Shield) of 5.5 turns rectangular spiral inductor using Taguchi's method. PGS is decrease method of parasite component by silicon substrate among dielectric loss reduction method. By using the taguchi's method, each parameter is fixed upon that PGS high poison(A), slot spacing(B), strip width(C) and overlap turn number(D) of PGS design parameter. Then we verified that percentage contribution and design sensitivity analysis of each parameter and level by signal to noise ratio of larger-the-better type. We consider percentage contribution and design sensitivity of each parameter and level, and then verify that model of optimization for PGS is lower inductance decreasing ratio and higher Q-factor increasing ratio by EM simulation.

• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1635-1637
• /
• 1998

This paper describes on the basic study for the insulation design of vacuum interrupter using Finite Element Method. For the basic study of insulation design, first, the maximum electric field was calculated on each curvature radius of arc shield and electrode. Second, the maximum electric field was also calculated on applied voltage and end shield with or not. Thus, the maximum electric field calculated have an effect on curvature radius and voltage polarity.

• Nuclear Engineering and Technology
• /
• v.50 no.1
• /
• pp.170-181
• /
• 2018

Because of the design and construction requirements, the nuclear structures need to maintain the structural integrity under both design state and extreme earthquake shaking. The base-isolation technology can significantly reduce the damages of structures under extreme earthquake events, and effectively protect the safeties of structures and internal equipment. This study proposes a base-isolation design for the AP1000 nuclear shield building on considering the performance requirements of the seismic isolation systems and devices of shield building. The seismic responses of isolated and nonisolated shield buildings subjected to design basis earthquake (DBE) shaking and beyond-design basis earthquake (BDBE) shaking are analyzed, and three different strategies for controlling the displacements subjected to BDBE shaking are performed. By comparing with nonisolated shield buildings, the floor acceleration spectra of isolated shield buildings, relative displacement, and base shear force are significantly reduced in high-frequency region. The results demonstrate that the base-isolation technology is an effective approach to maintain the structural integrity which subjected to both DBE and BDBE shaking. A displacement control design for isolation layers subjected to BDBE shaking, which adopts fluid dampers for controlling the horizontal displacement of isolation layer is developed. The effectiveness of this simple method is verified through numerical analysis.

• Journal of the Society of Disaster Information
• /
• v.20 no.1
• /
• pp.1-12
• /
• 2024

Purpose: The objective of this study was to improve the tunnel maintenance and monitoring technology by establishing the maintenance, management, and monitoring standards for shield and TBM tunnels, which had been applied more in recent years. Method: This study comprehensively analyzed and compared the data and model simulations of Seoul Subway Lines 7 and 9 and Bundang Line, shield and TBM tunnels in South Korea, tunnels in France and Japan, and Channel Tunnel in the UK. Result: This study set maintenance and monitoring standards when there was no design estimate based on numerical analyses such as section design and section analysis regarding the maintenance and monitoring section of shield and TBM tunnels. Conclusion: It is necessary to determine safety by comprehensively considering not only each monitoring item but also the changing trend and correlation of all items and compensation of the tunnel.

• Tunnel and Underground Space
• /
• v.25 no.5
• /
• pp.397-407
• /
• 2015

Estimation of shield TBM tunnelling-induced volume loss is of great importance for ground settlement control. This study proposed a simple method for evaluation of volume loss during TBM tunnlling, which is able to take into account of shield machine configurations and main driving data in calculation. The method was applied to analyze the tunnelling cases with earth pressure balanced and slurry pressure balanced shiled TBM, and mostly, reasonable agreements with monitoring results were found. Additional discussions were made for some disagreements.

• 한국터널공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.225-232
• /
• 2005

The construction of parallel tunnel by using the shield TBM method was increased recently. Accordingly the application and the propriety of the parallel shield TBM tunnels were studied through domestic and foreign construction cases herein. Also the behavior of tunnel structure and ground was evaluated by a numerical analysis with various ground conditions and the distance between the parallel tunnels. As a result, it was concluded that a deep investigation as well as a ground reinforcement was required with a ratio(L/D) of the distance between the parallel tunnels(L) to tunnel outer diameter(D) less than 0.5 because the Interference phenomenon was expected to occur. And the appropriateness of the application method of parallel shield TBM tunnel was validated through the 2-dimensional numerical analysis simulated the process of excavation after the ground reinforcement in the starting area of the OOO construction site with the ratio(L/D) of 0.35.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.25-32
• /
• 2001

Doosan Construction & Engineering Co., Ltd is building a railway tunnel beneath the Soo-Young River connecting MinLak Station and Centum City Station, a section 230, subway line 2, Pusan City, Korea. When completed the tunnel will have a finished inner diameter of 6.5m(21.311) throughout its total length of 840m(420m = 0.52 miles, Two Single Track Tunnel : 420m＋420m). The ground profile of the face toward shield machine is composed of multi layers, silty clay, clayey gravel, soft rock etc. This research paper is to predict ground deformation and variation of stresses around tunnel using Hyperbolic model, and to reflect the works on the next shield tunneling project. And this research paper is analyzed data of measuring instrument (such as settlement gauge, inclinometer, Multiple extensometer, etc.) which is installed along tunnel line for safety of tunnel. For calculations, the finite difference Method is applied. Backfill grouting material is supposed to have instantly strength of 10kg/$\textrm{cm}^2$ above, although its strength is available after 24 hours passed.

• Structural Engineering and Mechanics
• /
• v.11 no.6
• /
• pp.651-662
• /
• 2001

In order to investigate the seismic behavior and seismic design methods in the transverse direction of a shield tunnel, a series of model shaking table tests and a two-dimensional finite element dynamic analysis on the tests are carried out. Two kinds of static analytical methods based on ground-tunnel composite finite element model and beam-spring element model are proposed, and the validity of the static analyses is verified by model shaking table tests. The investigation concerns the dynamic response behavior of a tunnel and the ground, the interaction between the tunnel and ground, and an evaluation of different seismic design methods. Results of the investigation indicate that the shield tunnel follows the surrounding ground in displacement and dynamic characteristics in the transverse direction; also, the static analytical methods proposed by the authors can be used directly as the seismic design methods in the transverse direction of a shield tunnel.