• Geomechanics and Engineering
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• 제9권4호
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• pp.513-530
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• 2015

Commonly, the base stability of sheeted excavation pits against seepage failure by heave is evaluated by using two-dimensional groundwater flow models and Terzaghi's failure criterion. The objective of the present study is to investigate the effect of three-dimensional groundwater flow on the heave for sheeted excavation pits with various dimensions. For this purpose, the steady-state groundwater flow analyses are performed by using the finite element program ABAQUS 6.12. It has been shown that, in homogeneous soils depending on the ratio of half of excavation width to embedment depth b/D, the ratio of safety factor obtained from 3D analyses to that obtained from 2D analyses $FS_{(3D)}/FS_{(2D)}$ can reach up to 1.56 and 1.34 for square and circular shaped excavations, respectively. As failure body, both an infinitesimal soil column adjacent to the wall (Baumgart & Davidenkoff's criterion) and a three-dimensional failure body with the width suggested by Terzaghi for two-dimensional cases are used. It has been shown that the ratio of $FS_{(Terzaghi)}/FS_{(Davidenkoff)}$ varies between 0.75 and 0.94 depending on the ratio of b/D. Additionally, the effects of model size, the shape of excavation pit and anisotropic permeability on the heave are studied. Finally, the problem is investigated for excavation pits in stratified soils, and important points are emphasized.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.49-83
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• 2005

ESCP Project showed an urban excavation case and introduced design method for case of Soil-Structure behavior in urban excavation. In this case, a retaining structures design to analysis the behavior of retaining wall and adjacent structures in urban excavations was applied by using a Elasto-plastic beam and limit Equilibrium analysis and soil-structure interaction analysis. Reliable design of earth retaining structures and the ground adjacent to braced wall in urban excavation are often difficult due to many variable factors. The ground settlement and the damage of adjacent structures in urban excavation has been an imprtant issue. Therefore, the stability of the adjacent structures must be secured with the excavation support and research on the protection of adjacent structure is necessary.

• 한국지반공학회논문집
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• 제16권1호
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• pp.191-201
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• 2000

본 연구에서는 굴착부지가 넓고 지하수위가 높은 점성토지반에 얕은 굴착시 종래에 널리 적용되었던 강널말뚝 흙막이공 대신 줄말뚝을 이용한 흙막이공을 제안하였다. 줄말뚝을 이용한 흙막이 구조물의 거동을 관찰하기 위하여 지하굴착기간 동안 경사계 및 지하수위계를 설치하여 말뚝과 지반의 수평변위와 지하수위 변화를 조사하였다. 현장계측결과 말뚝과 지반의 변형거동은 굴착면 기울기, 말뚝두부구속조건, 말뚝설치간격, 굴착지반의 안정수 등의 요소에 영향을 받는 것으로 나타났다. 그리고 줄말뚝을 이용한 흙막이공의 시공성과 안정성뿐만 아니라 근접시공의 문제점이 없는 연약지반에서는 강널말뚝 흙막이공보다 경제적인 공법임을 확인하였다.

• 드라이브 ㆍ 컨트롤
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• 제18권2호
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• pp.20-31
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• 2021

An excavator is a construction machine that can perform various tasks such as trenching, piping, excavating, slope cutting, grading, and rock demolishing. In the 2010s, unmanned construction equipment using ICT technology was continuously developed. In this paper, the path design process was studied to implement the output data of the decision stage, and the path design algorithm was developed. For example, the output data of the decision stage were terrain data around the excavator, excavator mechanism information, excavator hydraulic information, the position and posture of the bucket at key points, the speed of the desired bucket path, and the required excavation volume. The result of the path design was the movement of the hydraulic cylinder, boom arm, bucket, and bucket edge. The core functions of the path design algorithm are the function of avoiding impact during the excavation process, the function to calculate the excavation depth that satisfies the required excavation volume, and the function that allows the bucket to pass through the main points of the excavation process while maintaining the speed of the desired path. In particular, in the process of developing the last function, the node tracking method expressed in the path design table was newly developed. The path design algorithm was verified as this path design satisfied the JCMAS H02 requirement.

• Geomechanics and Engineering
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• 제30권2호
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• pp.153-167
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• 2022

This study proposes a method to analyze the distribution of coal porosity disturbances after the excavation of ultra-large-diameter water jet boreholes using a coal wetting and softening model. The high-pressure jet is regarded as a short-term high-pressure water injection process. The water injection range is the coal softening range. The time when the reference point of the borehole wall is shocked by the high-pressure water column is equivalent to the time of high-pressure water injection of the coal wall. The influence of roadway excavation with support and borehole diameter on the ultra-large-diameter jet drilling excavation is also studied. The coal core around the borehole is used to measure the gas permeability for determining the porosity disturbance distribution of the coal in the sampling plane to verify the correctness of the simulation results. Results show that the excavation borehole is beneficial to the expansion of the roadway excavation disturbance, and the expansion distance of the roadway excavation disturbance has a quadratic relationship with the borehole diameter. Wetting and softening of the coal around the borehole wall will promote the uniform distribution of the overall porosity disturbance and reduce the amplitude of disturbance fluctuations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.895-902
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• 2010

The method in a bid to make better use of limited urban space amidst increasingly expanding urban area have been attempted in various ways. Efficient using underground space is one of the examples. The pipe roof and excavation for underground crossing implemented in this study was the part of evaluation of such attempt. However, the pipe roof method for underground crossing may cause the ground surface to be uplifted or settled down, having effect on structure above the ground. Thus in this study, a laboratory model test designed to evaluate the effect on surface during implementing pipe roof and excavation was carried out. The ground displacement during pipe roof advancing and excavation is usually occurred in a radial shape but as the study focused on trackbed, the evaluation included ground settlement only. Thus, appropriately-scaled model was selected considering domestic geological characteristics and operation characteristics of traditional and high-speed rail trains and the qualitative evaluation of displacement was carried out with a certain ground loss depending on excavation after categorizing trackbed settlement pattern depending on depth of top soil.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.88-94
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• 2003

In recent, as Republic of Korea has been interested in environmental problem increasingly and became a member of many organizations or institutions related to environmental preservation such as a Ramsar convention, fundamental and completed methods to prevent ground water's drying up and leakage in tunnel excavation are requested. In this paper, we have studied the anticipated problems by tunnel excavation under the wetland and described the effective designed method to maintain the wetland's ecosystem environment. To accomplish this purpose, firstly, we investigated the wetland's ecosystem, ground's hydraulic properties and analysed the foreign similar case for tunnel excavation near the wetland. And by numerical analysis, we analyzed the runoff and infiltration quantity of water and hydraulic behaviour properties by saturation and unsaturation concept in rock mass and wetland. Finally, we established the effective countermeasure to minimize the ecosystem's bad influence by tunnel excavation.

• 한국구조물진단유지관리공학회 논문집
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• 제12권5호
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• pp.116-124
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• 2008

본 연구에서는 원형수직구 굴착에 따른 Ring Beam의 거동을 평가하기 위하여 현장계측 자료의 분석과 평가, 굴착심도 변화에 따른 Ring Beam의 응력 특성 등의 비교분석을 구조해석에 기초하여 평가하였다. 그 결과, Ring Beam의 거동은 현장계측 및 구조해석 결과에서 유사한 경향을 나타내는 것을 알 수 있었다. 이로부터 굴착심도 변화에 따른 Ring Beam 거동은 본 연구에서 제안한 구조해석에 의해 예측할 수 있는 것을 확인하였다.

• 한국방재안전학회논문집
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• 제10권1호
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• pp.43-46
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• 2017

최근 도심지 포화로 전 세계적으로 지하공간개발이 활발히 진행되고 있으며 굴착공사는 지상 및 지하의 굴착 인접 구조물에 의한 다양한 굴착공법으로 시공이 주로 이루어지고 있다. 굴착공사 중 시공 부주의나 시공기술 미흡, 지하수 유출, 급격한 지층의 변화에 대응실패, 토류 시스템 구성품의 문제등으로 인해 각종 지반함몰 사고가 발생하고 있다. 지반함몰 방지를 위해 지반조사 분석을 통한 지반함몰 위험영향인자를 도출하고자 한다. 최근 75개소 지반조사값을 토대로 지반함몰 요인을 분석하고 조사항목으로는 지역별, 통일분류법(U.S.C.S), 공법, 굴착심도를 통해 분석을 하였다.

• 터널과지하공간
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• 제10권1호
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• pp.25-32
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• 2000

본 논문에서는 기존의 불연속 변형 해석(DDA)방법에 대한 두 가지 방향의 새로운 개선 방법들이 제시되었다. 이 개선 방법들은 암반에 연속적인 하중 재하 또는 제하, 그리고 록볼트, 숏크리트와 콘크리트 가이닝에 의한 보강으로 구성되었다. 이 방법들에 의하여 추가로 개선된 새로운 DDA프로그램에 대한 몇 가지 적용 예들이 제시되었다. 또한, 경부고속철도 공사의 일부인 운주 터널의 지하굴착에 대한 시뮬레이션을 통하여 굴착순서, 그리고 록볼트와 숏코리트에 의한 보강이 터널안정에 미치는 영향을 연구하였다. 그 결과 부적절한굴착순서는 터널의 안정성에 악영향을 미치나, 록볼트와 숏크리트에 의한 보강은 터널을 안정화 시킨다는 사실을 밝혀내었다. 그 결과 두 가지 개선방법이 추가된 DDA프로그램은 지하구조물 설계에 있어서 유용한 해석방법으로 사용될 수 있다는 사실을 보여주었다. 특히 시공단계(굴착, 보강)를 보다 사실적으로 시뮬레이션 할 수 있다.