• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.871-885
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• 2017

Nowadays, the construction of tunnels with a shallow depth drastically in urban areas increases. But the effect of sidewall displacement in shallow tunnel on its behavior is not well known yet. Most studies on the shallow tunnel have been limited to the stability and the failure of the tunnel and the adjacent ground in plane strain state. Therefore, the model tests were conducted in a model ground which was built with carbon rods, in order to investigate the impact of the tunnel sidewall displacement on the lateral load transfer to the adjacent ground. The lateral displacement of the tunnel sidewall and the load transfered to the adjacent ground were measured in model tests for various overburdens (0.50D, 0.75D, 1.00D, 1.25D). As results, if the cover depth of tunnel was over a constant depth (0.75D) in a shallow tunnel, the tunnel sidewall was failed with a constant shape not depending on the tunnel cover depth and also not affected by the opposite side of the wall. But, if the cover depth of tunnel was under a constant depth (0.75D), the failure of the tunnel sidewall could affect the opposite sidewall. In addition, if the displacement of tunnel sidewall with 50% of the critical displacement occurred, the tunnel failure was found to be at least 75%. However, additional studies are deemed necessary, since they may differ depending on the ground conditions.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.5
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• pp.761-778
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• 2017

The need of the underground space for the infrastructures in urban area is increasing, and especially the demand for shallow tunnels increased drastically. It is very important that the shallow tunnel in the urban area should fulfill not only its own safety conditions but also the safety condition for the adjacent structures and the surrounding sub-structure. Most of the studies on the behavior of shallow tunnels concentrated only on their behaviors due to the local deformation of the tunnel, such as tunnel crown or tunnel sidewall. However, few studies have been performed for the behavior of the shallow tunnel due to the deformation of the entire tunnel. Therefore, in this study the behavior of the surrounding ground and the stability caused by deformation of the whole tunnel were studied. For that purpose, model tests were performed for the various ground surface slopes and the cover depth of the tunnel. The model tunnel (width 300 mm, height 200 mm) could be simulationally deformed in the vertical and horizontal direction. The model ground was built by using carbon rods of three types (4 mm, 6 mm, 8 mm), in various surface slopes and cover depth of the tunnel. The subsidence of ground surface, the load on the tunnel crown and the sidewall, and the transferred load near tunnel were measured. As results, the ground surface subsided above the tunnel, and its amount decreased as the distance from the tunnel increased. The influence of a tunnel ceased in a certain distance from the tunnel. At the inclined ground surface, the wider subsidence has been occurred. The loads on the crown and the sidewall were clearly visible, but there was no effect of the surface slope at a certain depth. The load transfer on the adjacent ground was larger when the cover depth (on the horizontal surface) was lager. The higher the level (on the inclined surface), the wider and smaller it appeared. On the shallow tunnel under inclined surface, the transfer of the ambient load on the tunnel sidewall (low side) was clearly visible.

• Journal of the Korean Geotechnical Society
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• v.35 no.5
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• pp.21-30
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• 2019

While the study of the shallow tunnel has been mainly on the longitudinal load transfer and horizontal surface conditions, the study of the ground behavior of shallow tunnel under the slope is not sufficient. Therefore, in this study on the ground behavior around a tunnel due to the sidewall deformation of shallow tunnel under the slope that is excavated in longitudinal direction, a scale-down model test has been performed. The model tunnel has the dimension of 320 mm wide, 210 mm high and 55 mm long with enough material strength in aluminum and the model ground has the uniform ground conditions by 3 types of carbon rods. The model test has been performed with the variables of slopes and the cover depths by controlling the tunnel sidewall deformation, and the change of sidewall-load, load transfer, ground subsidence was monitored and analyzed. According to the increase of the slope, the maximum ground subsidence increased by 20~39% compared to the horizontal surface. The load ratio increased by maximum 20% in the tunnel crown and decreased in sidewall according to the surface slope. The load transfer shows maximum 128% of increase at the cover depth of 1.0D, while at the 1.5D cover depth it shows non-critical difference from horizontal surface. The slope has major effects on load transfer at the cover depth of 1.0D.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.108-108
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• 2004

전동차의 차체는 최대승객하중의 운행조건 하에서 시스템의 기능을 만족하도록 강성 및 강도를 갖도록 되어 있으며, 수직하중 및 수평하중을 지지하는 언더프레임(Under Frame), 측벽의 하중을 지지하는 측면구조틀(Side Frame) 지붕을 구성하는 지붕구조틀(Roof Frame), 끝막이 골조(End Frame)로 구성되어 있다.(중략)

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.55-60
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• 2010

The honeycomb composite joint structure designed for application to a tilting KTX railroad car body is subjected to bending loads of a cantilever type. Honeycomb sandwich composite panel-joint attached in the real tilting car body was fabricated and sectioned as several beam-joint specimens for the bending test. The fracture behaviors of these specimens under static loads were different from those under cyclic loads. Static bending loads caused shear deformation and fracture in the honeycomb core region, while fatigue cyclic bend loading caused delamination along the interface between the composite skin and the honeycomb core, and/or caused a fracture in the welded part jointed with the steel under-frame. These fracture behaviors could occur in other industrial honeycomb composite joints with similar sub-structures, and be used for improving design parameters of a honeycomb composite joint structure.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.36-41
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• 2008

Using the finite element analysis, this paper presents the strength safety of a side wall of an outer tank and a roof structures in a full containment LNG storage tank system. The outer tank structure in which is constructed with a prestressed concrete is forced by internal hydrostatic and hydrodynamic pressures of a leaked LNG and an external wind pressure including a typhoon one. The FEM computed results show that the ring beam between a side wall of an outer tank and a roof structure supports most of the internal and the external loads. This means that the design point of the outer tank system is a ring beam structure and the other one is a center part of the roof structure. In this FE analysis model of a full containment LNG tank system, the outer tank and the roof structures are safe for the given combined loads such as an internal leaked LNG pressure and an external typhoon pressure.

• Tunnel and Underground Space
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• v.28 no.2
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• pp.142-155
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• 2018

The ${\bigcirc}{\bigcirc}$ mine has irregularly developed stratum around the ore body. The purpose of this study is to array irregular stratum thickness systematically for effective roof bolting and to implement a supporting system corresponding to it. The number of 81 cases combined with stratum thicknesses was limited to 9 cases by robust design. For each case, the load height which can act as a roof load was determined by the characteristics of stratum and RMR. The load range due to the load height is calculated assuming block shaped and arch shape. The support load of the roof bolt was considered as the average load of the two methods. Numerical analysis results of the support design showed that the cable bolt was more effective for the roof supporting fully grouted than the anchoring type. As a result of the construction, it was possible to control the roof, but all of the roof was gradually sinking downward due to the deformation of the side wall of the mine tunnel.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.85-90
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• 2007

This paper presents the finite element analysis on the strength safety of a full containment LNG storage tank system with damping safety structures. For the FEM analysis of the inner tank, the combined loads in which are related to a hydrostatic pressure, a cryogenic temperature load, BOG pressure, LNG weight, and a sinking force at the comer of the inner tank have been applied to the inner tank structure. The FEM computed results show that the conventional inner tank is safe for the given combined loads, but the damping safety structure such as compressive springs may be more useful structures to increase the safety of the tank system. The increased stiffness and the appropriate position of the springs are very important design parameters for increasing the damping strength safety of the tank system.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.35-42
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• 2002

The roles and importance of the application of simulator in harbor and waterway design are emphasized. On this paper Different methods of simulation and their application are described. A large-scale simulation concept, group simulation, is proposed. Requirements of the simulation for accomplishing the tasks properly and effectively are suggested. Some points on modeling of ship hydrodynamics and environmental factors. which are critical especially in waterway desing simulation, are discussed and algorisms presented.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.107-115
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• 2011

In this study, the vibration analysis of the underground box structures induced train movement is studied. In order to perform these analysis, dynamic data, which was measured when subway is in service, are gained by attaching accelerometers on the structure such as lower beam, lateral wall and upper slab. Also, accelerometers are attached on the lower beams and side walls of the gravel ballast and concrete ballast sections in order to compare vibration due to ballast materials. The vibration results of upper slabs and lower beams reveal that the vibration on the upper slabs is greater than the lower beams. Also, the results of the crack gauge on the upper slab show that crack width dose not change due to vibration, These means that the effect of the vibration on the structure is very limited. In order to evaluate the vibration of the structure, acceleration unit is converted to velocity unit comparing with the existing velocity data gained from the platforms.