• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.5-18
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• 2009

In construction of buildings in Korea, the buildings are frequently founded on the weathered ground (weathered soil/rock, fractured rock). In this case, to make a full use of a bearing capacity of a weathered ground for economic design, the shallow mat foundation system could be used. In this study, we have researched three cases of mat foundations on the weathered ground in Korea, and analyzed and considered the design procedures and the reinforcing methods. That is, we have considered the detail design, analysis proceedings, the ground settlement evaluation proceedings, the rock face mapping evaluations after excavation and reinforcing methods of the mat foundation on the weathered ground. And large scale plate load tests on the weathered ground supporting the mat foundation were performed and also load bearing capacity and settlement of actual mat foundation, considering the scale effect, were evaluated.

• Journal of the Korean GEO-environmental Society
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• v.16 no.12
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• pp.37-43
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• 2015

Ground characteristics is important in tunnel structure utilizing the strength of underground. In the case of the fault fracture zone such as weak soil conditions exists in the tunnel section and groundwater leaching occurs at the same time, it happens to occur to excessive displacement or collapse of tunnel frequently. Fault fracture zone is an important factor that determines the direction of displacement and the collapse of the tunnel under construction. Behavior of fault fracture zone is determined depending on the size and orientation of the surface portion of the tunnel. If the groundwater occurs in the face of tunnel, groundwater causes displacement and collapse. And the collapse characteristics of tunnel is a major factor in determining that the time-dependent behavior. It is difficult to accurately predict groundwater leaching from the fault fracture zone in the numerical analysis method and analyze the interaction behavior of groundwater and fault fracture zone. Therefore numerical analysis method has limitations the analysis of ground water in the ground which the fault fracture zone and groundwater occurs at the same time. It is required to comprehensively predict the behavior of tunnel and case studies of tunnel construction. Thus, the location of fault fracture zone is an important factor that determines the direction of displacement and the collapse of the tunnel. In this study, behavior characteristics of the tunnel according to the location of the fault fracture was analyzed.

• Journal of the Korean Geotechnical Society
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• v.20 no.5
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• pp.135-143
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• 2004

In the land section of marine bridge construction site, to confirm the end bearing of large diameter drilled shaft constructed in the fault zone which was discovered unexpectedly, the hi-directional end loading tests were performed. The objectives of this study are to confirm the end bearing of the pile constructed in fault zone and the increasing effect of end bearing after grouting the base ground beneath the pile toe. After grouting the pile base ground, the settlement of pile base decreased considerably and the pile base resistance increased more than twice.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.4
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• pp.341-354
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• 2016

This article is to apply the tunnel support system selected after comparatively analyzing of RMR and tunnel instrumentation between the tunnel behavior characteristic predicted through geotechnical investigations and the numerical analysis at the design stage and the properties deformation occurred at the construction stage. This attempt results from the behavior characteristic of the tunnel excavation ground shown differently in accordance with the ground quality and reinforcement method. This, therefore, provide the data and results analysed the actual decision RMR-crown settlement & convergence and reduction of material property of ground as parameters. Also, it's shown that the tunnel designer is able to predict tunnel behavior characteristic when designing in bedrock areas excessively distributed faults and fractured zones.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.281-290
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• 2003

In order to investigate recycling possibility as a construction material of oyster-shells, the geotechnical characteristics including permeability, confined compression and shear strength of crushed oyster shell were quantitatively examined in terms of fineness modulus and relative density of crushed oyster-shell. Experimental results show that the crushed oyster-shells are lighter than sand in weight, and have similar characteristics on permeability and shear strength to sandy soils. The oyster-shell can be considered as highly crushable material but not much crushable with existing high loads. Based on the laboratory test results, it is highly fudged that the crushed oyster-shell can be a substitute of sand as SCP materials.

• Geotechnical Engineering
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• v.24 no.8
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• pp.34-41
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• 2008

• Proceedings of the Korean Geotechical Society Conference
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• 2002.11a
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• pp.188-208
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• 2002

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.3
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• pp.235-245
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• 2002

The purpose of this study is to figure out the tendency of tunnel convergence during excavation and to present a methodology for the prediction of a fault zone ahead of a tunnel face by analyzing three dimensional displacements in various ways. 3-D numerical analysis was performed to investigate changes of tunnel convergence vectors near a fault zone and to propose a flow chart for predicting fault zones. Results of the site investigation and results of trend line analysis of in-situ data were compared to verify the usefulness of a trend line analysis. It is concluded that the orientation of faults can be predicted by using stereonets and the direction of initial stresses can be predicted from the arm length of a displacement vector as a tunnel approaches fault zones. The results of the trend line analysis coincided with those of the site investigation, and a methodology for the prediction of a fault zone was proposed.

• Geotechnical Engineering
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• v.35 no.5
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• pp.25-38
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• 2019

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.403-415
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• 2014

Recently, the temperature rise in the summer due to climate change, power usage is increasing rapidly. As a result, power generation facilities have been newly completed and the need for ultra-high-voltage transmission line for power transmission of electricity to the urban area has increased. The mechanized tunnelling method using a shield TBM have an advantage that it can minimize vibrations transmitted to the ground and ground subsidence as compared with the conventional tunnelling method. Despite the popularity of shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Thus, in this study, the effect of fractured zone ahead of tunnel face on the mechanical behavior of the shield TBM cable tunnel is investigated. In addition, it is intended to compare the behavior characteristics of the fractured zone with continuous model and applying the interface elements. Tunnelling with shield TBM is simulated using 3D FEM. According to the change of the direction and magnitude of the fractured zone, Sectional forces such as axial force, shear force and bending moment are monitored and vertical displacement at the ground surface is measured. Based on the stability analysis with the results obtained from the numerical analysis, it is possible to predict fractured zone ahead of the shield TBM and ensure the stability of the tunnel structure.