• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.77-88
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• 2006

A series of model tests were performed to investigate the ground deformation during trench excavation for diaphragm walls. An apparatus was manufactured to observe the failure pattern of a slurry-supported trench in sandy ground. Ground deformations including settlement and lateral displacement of the surrounding ground adjacent to the trench were carefully monitored during excavation. Experimental observations indicated that the settlement of the adjacent ground increased with closing to the trench. Especially, the considerable settlement occurred at the distance which was equal to 40% of the excavation depth. And, the higher settlement was obtained when the relative density of ground was looser and the ground water table was higher. Also, the lateral wall face of excavated trench was bulged with lowering the slurry level In stages and then the upper part of trench failed finally. The envelope of ground surface settlement could be represented as a hyperbolic line and the measured settlement was smaller than those predicted by Clough and O'Rourke (1990).

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.27-39
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• 2005

목적구조물의 건설을 위한 지반굴착시 지반거동에 대하여 보다 현실적이고 개념적으로 제시하여 정보화시공시 보다 안전시공을 위하여 지분굴착에 따른 지반거동에 대한 이해를 도모하고 신속한 문제해결 기술에 활용되도록 하였다. 굴착시에 대하여서는 개착 뿐만 아니라 터널의 굴착도 포함하여 지반거동을 이해하기위한 기본개념과 아울러 지반거동에 대한 정성적인 분석기법에 대하여서도 제시하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.87-99
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• 2023

Ground excavation inevitably causes ground displacement of adjacent ground, and structures and facilities exposed to ground displacement may suffer various damages. Therefore, in order to minimize the damage and damage to adjacent structures and facilities caused by excavation, ground displacement (settlement and horizontal displacement) in the adjacent ground caused by excavation must first be predicted. There is many ground displacement information induced by general braced cut excavation, but the information is not enough for circular shaft excavation. This study aims to provide information on the estimation of ground settlement caused by circular shaft excavation through the case analysis of circular shafts and comparison with braced cut excavation. From this study, it was found that the use of the settlement criterion of braced cut excavation as the settlement management criterion for circular shaft excavation is a conservative approach in terms of safety. But when considering the economic aspect, it may result in overdesign of the wall and therefore, a more reasonable settlement criterion can be needed for circular shaft excavation.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03a
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• pp.343-365
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• 2004

대도시 인구증가와 경제성장으로 인하여 제한된 공간을 효율적으로 사용하기 위한 노력이 계속되어 왔다. 도로의 확충, 지하철 건설, 대형구조물 건설 등 산업인프라의 확충과 더불어 지반굴착이 차지하는 비중이 점점 증대되고 있다. 또한 지상공간에 대한 제한으로 지하공간 활용에 대한 관심이 증대되었고 이에 따라 최근 대심도 굴착사례가 증가되고 있는 실정이다.(중략)

• Geotechnical Engineering
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• v.1 no.2
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• pp.81-92
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• 1985

Braced excavation for a new building was carried out at a very close proximity of an existing tall building of T.hick columns are supported by indict.ideal spread footings on sand layer The excavation was planned to reach far below the footing level of the existing building. To assess the foundation performance and stability of the existing building, the behavior of 9round subjected to loss of confinement from excavation was analytically studied using finite element method. Field instrumentation was also conducted to monitor the actual ground responses during excavation. Based on these studies, various remedial measures weere taken to minimize the adverse effects to the building, and excavation was successfully completed. This paper presents the results from the analytical studies and field monitoring, and measured and measured responses at different stages of excavation.

• Journal of the Korean Geosynthetics Society
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• v.11 no.4
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• pp.45-53
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• 2012

Ground drilling is a common method to conduct site investigation, soil improvement, and pile installation. In the point of construction ground drilling requires electrical energy to drill a hole in ground in which the energy exerts into the motor located on the head of auger and generates rotational power. In this paper it is verified that the exerted electrical energy is closely related to the strength characteristics of ground. Measurement sensors, recording system, and drilling system were developed to obtain exerted motor current and drilling depth and laboratory soil box tests were carried out. The measured motor current and boring depth were applied to predict SPT N-value and the prediction results were compared to SPT N-value of laboratory tests. The test results show that the exerted electrical energy to bore ground be a good index to estimate SPT N-value.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.179-191
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• 2000

본 연구에서는 화강토 지반상의 자립식 diaphragm wall의 거동을 연구하기 위하여 벽체의 근입깊이비, 지하수위 및 굴착조건(연속 및 단계굴착)을 변화시키면서 원심모형시럼을 수행하였다. 원심모형실험시 지반굴착은 흙과 동일한 밀도로 혼합된 zine chloride 용액이 배수되도록 밸브를 조작하여 실시하였으며, 굴착에 의해 발생되는 지반의 변형괴 벽체의 변위 및 휨모멘트를 시간경과에 따라 측정하였다. 실험결과, 벽체의 근입깊이비가 증가함에 따라 벽체의 휨모멘트는 증가하는 반면, 굴착과정동안 배면측에서의 간극수압 감소속도는 감소하였다. 최종 굴착단계에서 굴착후 시간경과에 따른 침하량은 굴착과정중의 침하？에 비해 5~7% 정도를 나타내었다. 최대표면침하량과 벽체변위를 굴착깊이로 정규화한 결과 최대 침하량은 벽체 변위량의 0.8~1.2배9평균0.91배)사이에 분포하였다. 굴착깊이로 전규화한 벽체변위와 근입깊이와의 관계는 지수함수식으로 제안하였다. 파괴면은 직선적인 형태로 파괴면내의 배면측 지반은 벽체를 향하여 하향의 변위를 일으키면서 벽체의 회전에 의해 파괴되었으며, 퐈괴면의 각도는 66~72.5$^{\circ}$정도로 이론적인 파괴면의 각도보다 크게 평가되었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5C
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• pp.239-250
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• 2009

Tunnelling-induced settlements and lateral ground movements have been investigated by numerical parametric studies considering ground condition, excavation characteristics, and ground layers. Before the numerical study the existing methods of ground movement estimation have been collected and analysed to have some information of ground movements and to improve them providing a fundamental material for the numerical study. Numerical model simulation has been performed of a physical model test of tunnel excavation in which the ground movements were measured reliably and the results have been used to determine the numerical approach and the appropriate soil constitutive mode. With this procedure done, the results of numerical parametric studies have been put together to analyze and understand tunnelling-induced settlements and lateral ground movements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4C
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• pp.153-162
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• 2009

This paper investigates the effects of excavation-induced ground movements on nearby structures, considering soil-structure interactions of different soil and structural characteristics. The response of four and two-story block structures, which are subjected to excavation-induced advancing ground movements, are investigated in different soil conditions using numerical analysis. The structures for numerical analysis are modelled to have cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four and two-story block structures are investigated with advancing ground movement phases and compared with the response of structures which are subjected to excavation-induced total ground movement. The response of structures is compared among others in terms of the magnitude and shape of deformations and cracks in structures for different structure and ground conditions. The results of the comparison provide a background for better understandings for controlling and minimizing building damage on nearby structures due to excavation-induced ground movements.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06b
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• pp.85-115
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• 2003

토공작업시 굴착난이도(토층, 리핑암, 발파암)를 판정하는 기준으로는 암반의 강도, 풍화정도, 불연속면 간격과 같은 여러 가지 암반의 공학적 특성 및 지반의 탄성파 속도 등이 사용된다. 그러나 실제 토공 작업시의 굴착난이도 평가는 탄성파 탐사와 같은 암석ㆍ암반의 정량적인 판단기준에 근거하지 않고 단지 현장 기술자들의 육안관찰에 의존하여 굴착난이도를 구분하고 있는 실정이다. 본 논문은 실내시험 및 현장시험, 현장굴착난이도 평가 및 탄성파탐사 등을 실시하여 여러 암석에 대한 강도특성을 파악한 것을 근거로 현장에서 사용할 수 있는 암반굴착난이도 평가법의 Checklist를 제안하였다.