• Journal of the Korean GEO-environmental Society
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• v.18 no.1
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• pp.5-12
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• 2017

The damage of the tunnel lining on the cold regions can be represented by cracks and leaks caused by freezing of ground water. However, domestically, the relevant construction guidelines are not provided so far. Thus, in this research, the mechanical behavior and thermal conductivity of designated tunnel area are measured using instrumentation system installed in the lining concrete inside tunnels in order to analysis their behavior with regard to temperature variations. Previous research mainly focused on the effect of temperature on the tunnel lining based on the air and initial ground temperature at urban regions. Thus, this study analyzes effects of air temperature and initial ground temperature of designated tunnel area at the cold regions. The temperature of the groundwater at the backfill of the tunnel lining are analyzed to evaluate the heating element. Numerical analyses are performed to evaluate the heating element with regard to the various initial ground temperatures.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.1
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• pp.1-18
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• 2007

This study is about an arrangement method of trapezoidal pre-cast segment lining that can be applied in shield tunnel construction. Trapezoidal segment lining is formed by assembling tapered pre-cast concrete segments taking advantage of the tapered shape of pre-cast segments upon delivery on site. By calculating tapering of the segments manufactured in single type and rotating the segments when putting them together, a variety of tunnel alignments can be arranged in the most efficient way. Once the design criteria and tunnel alignment (straight or curved) is analyzed, the sequence of assembling trapezoidal segments in compliance with tunnel alignment will be computed. On site an operator can utilize the softwareto automatically determine sequential arrangement of trapezoidal segments. When the actual arrangement of segmental lining is different from the computed output, the operator can input the actually measured values to coincide the computerized calculation with the real status of assembly. Then the adjustment will be the basis of subsequent arrangement of segments, thus the continuity of work can be guaranteed.

• Tunnel and Underground Space
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• v.15 no.5 s.58
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• pp.359-368
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• 2005

In case the overburden of a tunnel is too low to adopt NATM, cut and cover method generally can be chosen as alternative. However, in tunneling some area with very low or no overburden between two mountains, the cut and cover method requires additional construction of a couple of tunnel portals and the maintenance of portal slopes until backfilling is completed. As a solution for this problem, increasing the tunnel overburden by raising the ground level can be effective. This paper presents the case study for tunneling at C240 site in Taiwan High Speed Railway(THSR) in which soil-cement filling method was used for pre-banking before tunnel excavation. Cement content of filling material was $2\~4\%$ and thickness of filling a round was $130\~250\;mm$. The stability evaluation for the soil-cement slope and concrete lining of low cover tunnel was conducted by numerical analysis.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.95-102
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• 2020

Population concentration in urban areas has led traffic management a central issue. To mitigate traffic congestions, the government has planned to construct large-cross-section tunnels deep underground. This study focuses on estimating the damage caused to frame structures owing to tunnel excavation. When constructing a tunnel network deep underground, it is necessary to divide the main tunnel and connect the divergence tunnel to the ground surface. Ground settlement is caused by excavation of the adjacent divergence tunnel. Therefore, predicting ground settlement using diverse variables is necessary before performing damage estimation. We used the volume loss and cover-tunnel diameter ratio as the variables in this study. Applying the ground settlement values to the settlement induction device, we measured the extent of damage to frame structures due to displacement at specific points. The vertical and horizontal displacements that occur at these points were measured using preattached LVDT (Linear variable differential transformer), and the lateral strain and angular distortion were calculated using these displacements. The lateral strain and angular distortion are key parameters for structural damage estimation. A damage assessment chart comprises the "Negligible", "Very Slight Damage", "Slight Damage", "Moderate to Severe Damage", and "Severe to Very Severe Damage" categories was developed. This table was applied to steel frame and concrete frame structures for comparison.

• Computers and Concrete
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• v.31 no.5
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• pp.405-417
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• 2023

The submerged floating tunnel (SFT) is tethered by mooring lines anchored to the seabed, therefore, the structural integrity of the anchor should be sensitively managed. Despite their importance, reaction forces cannot be simply measured by attaching sensors or load cells because of the structural and environmental characteristics of the submerged structure. Therefore, we propose an effective method for estimating the reaction forces at the seabed anchor of a submerged floating tunnel using a structural pattern model. First, a structural pattern model is established to use the correlation between tunnel motion and anchor reactions via a deep learning algorithm. Once the pattern model is established, it is directly used to estimate the reaction forces by inputting the tunnel motion data, which can be directly measured inside the tunnel. Because the sequential characteristics of responses in the time domain should be considered, the long short-term memory (LSTM) algorithm is mainly used to recognize structural behavioral patterns. Using hydrodynamics-based simulations, big data on the structural behavior of the SFT under various waves were generated, and the prepared datasets were used to validate the proposed method. The simulation-based validation results clearly show that the proposed method can precisely estimate time-series reactions using only acceleration data. In addition to real-time structural health monitoring, the proposed method can be useful for forensics when an unexpected accident or failure is related to the seabed anchors of the SFT.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.624-629
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• 2008

When TBM excavates a tunnel, existing concrete lining segments are used as supporting structures for driving force. Axial stress on the lining segments are apt to be large in case of direct driving force. However, it drastically decline as it is farther and father from TBM and later, it tends to converge after a certain point. Such tendencies show similar results of finite element analysis. At the initial intervals, the values of finite element analysis are larger, while at the later intervals, the actual stress values are larger. It concludes that such tendencies are attributable to that the concrete lining segments have partially burst and cracked in the axial direction at the initial intervals. And differences of stresses at the later intervals are created by the changed plasticity of ground and the friction on the external sides of the lining segments.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.115-120
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• 2005

Impact seismic wave method is a method for non-destructive testing of concrete structure using of stress wave which is propagate and reflected from internal flaws within concrete structure and external surface. In this study, we performed frequency domain method using impact seismic wave test for safety diagnosis of civil engineering structure. And reflection method which is used for one-dimensional target such as tunnel lining and transmission method are compared with each other.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.225-231
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• 1996

The dense graded asphalt concrete materials have been used for construction of pavement for a long time. The performance of asphalt concrete pavement, however, is influenced by various factors including high temperature and heavy axle loads which cause plastic deformation. The plastic deformation is one of the main functional disadvantages of flexble pavement. In this study, the semi-rigid pavement is considered to solve the problem. A set of experimental evaluation on semi-rigid pavement material has been coducted in laboratory to obtain it's physical properties and serviceabilities. The results of tests, including compressive strength, flexural strength, ravelling and wheel tracking, show that the semi-rigid pavement has a good mechanical properties and serviceabilities. Consequently, the semi-rigid pavement may be suitable to bridge deck, tunnel, slow lane and parking area pavements.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.75-82
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• 2000

A huge offshore structures such as immersed tunnel, ice-resisting wall are continuously subjected to large force from water pressure, wave action and impact loads. Composite steel-concrete structure of sandwich system has profitable advantages for a huge offshore structures. This composite structures should exhibit a high degree of strength and ductility, because of concrete confining effect and the property of steel plate. Therefore, it endures large deformation and absorbs a great deal of energy until failure. In this study, nonlinear analysis for composite steel-concrete structure of sandwich system was carried out, and certify the effects of various parameters, elastic·plastic behavior characteristic, load-carrying and failure mechanism.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.829-832
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• 2004

FREP(Fiber Reinforced Epoxy Panel), the products of our company, was widely made full use of a field of the reinforced concrete. In particular, the FREP used for repair and reinforcement of the subway and tunnel is required flame retardative property. In this study, flame retardative FREP using flame retardant of non-halogen system was fabricated by impregnation method. Flame retardative grade was the third grade. Tensile strength, flexural strength, and compressive strength was 1,384, 1,298, and $1,450kg/cm^2$, respectively.