• Geomechanics and Engineering
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• v.14 no.6
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• pp.601-614
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• 2018

This study presents structural and parametric analyses on the behavior of an integrated and pile-bent abutment with mechanically stabilized earth wall (IPM) bridge. The IPM bridge is an integral abutment bridge (IAB) with partially protruded piles, which excludes earth pressure by means of a mechanically stabilized earth wall developed by the authors. The results of the analysis indicate that the IPM bridge, as any other IAB, is influenced to a large extent by temperature and time-dependent loads. When these loads are applied, the stress on a pile in the IPM bridge decreases as the displacement of the pile top increases, because the piles protrude from the ground surface and no soil reaction is generated on the protruded pile. Because the length of an IAB is restricted by the forces acting on its piles, the IPM bridge is an effective alternative to extend its length.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.72-80
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• 2006

Electric Power Steering (EPS) mechanism has become widely equipped in passenger vehicle due to the increasing environmental concerns and higher fuel efficiency. This paper describes the development of concurrent simulation technique and simulation integration technique of EPS control system with a dynamic vehicle system. A full vehicle model interacting with EPS control algorithm was concurrently simulated on a single bump road condition. The dynamic responses of vehicle chassis and steering system resulting from road surface impact were evaluated and compared with proving ground experimental data. The comparisons show reasonable agreement on tie-rod load, rack displacement, steering wheel torque and tire center acceleration. This concurrent simulation capability was employed fur EPS performance evaluation and calibration as well as for vehicle handling performance integration and synthesis.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.109-116
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• 2004

The dynamic behavior of the rectangular liquid storage structure is known to be greatly influenced by fluid-structure interaction. By mounting the liquid storage structure on the properly designed base isolators, dynamic response of the superstructure can be reduced. However, base isolators inevitably incur large displacement of the structure to the ground ·ind may give adverse effects on the sloshing height. This paper presents the analysis method for fluid-structure-isolator interaction in base-isolated rectangular liquid storage structures. In the method, the irrotational motion of invicid and incompressible ideal fluid is expressed by analytic solutions and the superstructure and isolators are properly modeled by finite element and bilinear model. Free surface sloshing motion, hydrodynamic pressure acting on the wall and structural response are obtained by the presented method.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.123-130
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• 2002

The ground-borne vibration from pile driving is causing many public discontents. However, because of the fact that the characteristics of wave propagation and attenuation are not well understood, systematic and effective vibration reduction measures can not be taken. This paper attempts to study the propagation of stress waves induced by the pile driving. To simulate the wave propagation in a semi-infinite domain, the so-called absorbing boundaries are incorporated in the finite element method and a series of numerical simulations is performed. Numerical results show that the surface displacement and velocity increase first and then decrease as the pile penetration depth becomes larges.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.845-862
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• 2009

Recently, Tunnel in soil has been designed frequently because Mountain Tunnel has been increased rapidly due to straight of horizontal curve and residents' complaints, tunnel portal has been planned at closed to surface for minimization of environmental damage. To excavate tunnel in soil, where displacement and crushing occur in tunnel face and crown because of unstable ground condition, appropriate reinforcement method needed. On this paper, through design and construction of the soil tunnel, consider application of reinforcement method, economical efficiency and stability.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.29-37
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• 2019

Synthetic Aperture Radar (SAR) observations are powerful tools to monitor surface's displacement very accurately, induced by earthquake, volcano, ground subsidence, glacier movement, etc. Especially, radar interferometry (InSAR) which utilizes phase information related to distance from sensor to target, can generate displacement map in line-of-sight direction with accuracy of a few cm or mm. Due to decorrelation effect, however, degradation of coherence in the InSAR application often prohibit from construction of differential interferogram. Offset tracking method is an alternative approach to make a two-dimensional displacement map using intensity information instead of the phase. However, there is limitation in that the offset tracking requires very intensive computation power and time. In this paper, efficiency of parallel computing has been investigated using high performance computer for estimation of glacier velocity. Two TanDEM-X SAR observations which were acquired on September 15, 2013 and September 26, 2013 over the Narsap Sermia in Southwestern Greenland were collected. Atotal of 56 of 2.4 GHz Intel Xeon processors(28 physical processors with hyperthreading) by operating with linux environment were utilized. The Gamma software was used for application of offset tracking by adjustment of the number of processors for the OpenMP parallel computing. The processing times of the offset tracking at the 256 by 256 pixels of window patch size at single and 56 cores are; 26,344 sec and 2,055 sec, respectively. It is impressive that the processing time could be reduced significantly about thirteen times (12.81) at the 56 cores usage. However, the parallel computing using all the processors prevent other background operations or functions. Except the offset tracking processing, optimum number of processors need to be evaluated for computing efficiency.

• Journal of the Korean GEO-environmental Society
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• v.17 no.4
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• pp.39-46
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• 2016

The final stability analysis of the tunnel structure is generally evaluated by performing site monitoring to determine whether or not the measured value through the convergence after the completion of excavation in the face. When the ground conditions are so poor, the reinforcement around the tunnel was applied for enhancing the stability of tunnels. For the additional tunnel crown collapse or excessive displacement have occurred under construction, correlation analysis were performed for the comparison construction and numeric analyses. In this paper, we investigated the collapse types, tunnel collapse were mostly occurs at the crown and they were analyzed because of the geological conditions in the collapse zone. And also, it was analyzed as being correlated in the crown of tunnel exists a fault fracture zone which extends to the surface part. Thus, in case of ground conditions such as fault fracture zone with a tunnel extending from the crown to the surface, the behavior is larger than the behavior predicted by numerical method.

• Journal of the Korean Geotechnical Society
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• v.24 no.1
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• pp.61-70
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• 2008

The control and prediction of surface settlement, gradient and ground displacement are the main factors in shallow tunnel design and construction in urban area. For deformation analysis of shallow tunnel due to excavation it is important to identify possible deformation mechanism of shear bands developing from tunnel shoulder to the ground surface. This paper investigaties quantitatively the deformation behavior of shallow tunneling by model tunnel test and strain softening analysis Incorporating the reduction of shear stiffness and strength parameters. The comparison of model tunnel test result and numerical simulation using strain softening analysis showed good agreement in crown settlement, normalized subsidence settlement and developing shear bands above tunnel shoulder. In this study, it is blown that the strain softening modeling is applicable to the nonlinear deformation analysis of shallow tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.2
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• pp.105-116
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• 2010

The estimation of surface settlement, ground behavior and tunnel displacement are the main factors in urban tunnel design with shallow depth and unconsolidated soil. On deformation analysis of shallow tunnel, it is important to identify possible deformation mechanism of shear bands developing from tunnel shoulder to the ground surface. This paper investigated the effects of key design parameter affecting deformation behavior by numerical analysis using nonlinear model incorporating the reduction of shear stiffness and strength parameters with the increment of the maximum shear strain after the initiation of plastic yielding. Numerical parametric studies are carried out to consider the reduction of shear stiffness and strength parameters, horizontal stress ratio, cohesion and shotcrete thickness.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.451-454
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• 2007

There is an inseparable relation between human race and engineering work. As world developed into highly industrialized society, a diversity of large structures is being built up correspondently to limited topographical circumstance. Though large structures are national establishments which provide us with convenience of life, there are some disastrous possibilities which were never predicted such as ground subsidence and degradation. It is very difficult to analyze the volume of total metamorphosis with the relative displacement measurement system which is now used and it is impossible to know whether there is structural metamorphosis within a permissible range of design or not. In this research with an object of 13-year-old earthen dam, through generating point-cloud which has 3D spatial coordinates(x, y, z) of this dam by means of 3D Laser Scanning, we can get real configuration data of slanting surface of this dam with this method of getting a number of 3D spatial coordinates(x, y, z). It gives 3D spatial model to us and we can get various information of this dam such as the distance of slanting surface of dam, dimensions and cubic volume. It can be made full use of as important source material of reinforcement and maintenance works to detect previously the bulging of the dam through this research.