연약지반 표층처리에 대한 기술현황 및 가열개량공법개발

임은상,한희수,박민철,신백철 한국지반환경공학회 2012 지반환경 Vol.13 No.3

K-water연구원 댐안전연구소 소개

임은상 한국지반환경공학회 2010 지반환경 Vol.11 No.1

A Study on Particle Crushing of Rock-fill Dam Materials

임은상,김태훈 한국지반공학회 2009 international journal of geo-engineering Vol.1 No.1

Earth and rock fill dam is our typical dam because of their inherent flexibility and adaptability to various foundation conditions. In order to secure structural safety, rock-fill materials are used angular particles obtained by blasting parent rock or rounded particles collected from river beds. Concrete-faces rock-fill dams (CFRD) and Concrete-faces gravel-fill dams (CFGD) have become popular in the last 20 years as a result of their good performance and low cost compared with the rock-fill dam. These Dams are also constructed by rubbles or gravels. A key factor in the design of the dams is the deformations induced during construction and upon reservoir filling. These can be predicted using the adequately defined stress-strain and strength properties. However, the stress-strain properties of rockfill are difficult to determine because the properties are affected by some factors such as particle grading, size and shape of particles, stress conditions, and particle crushing. In this study, testing of the behavior of the rock-fill materials are essential prerequisites to the realistic analysis and design of the CFGD. Earth and rock fill dam is our typical dam because of their inherent flexibility and adaptability to various foundation conditions. In order to secure structural safety, rock-fill materials are used angular particles obtained by blasting parent rock or rounded particles collected from river beds. Concrete-faces rock-fill dams (CFRD) and Concrete-faces gravel-fill dams (CFGD) have become popular in the last 20 years as a result of their good performance and low cost compared with the rock-fill dam. These Dams are also constructed by rubbles or gravels. A key factor in the design of the dams is the deformations induced during construction and upon reservoir filling. These can be predicted using the adequately defined stress-strain and strength properties. However, the stress-strain properties of rockfill are difficult to determine because the properties are affected by some factors such as particle grading, size and shape of particles, stress conditions, and particle crushing. In this study, testing of the behavior of the rock-fill materials are essential prerequisites to the realistic analysis and design of the CFGD.

이상치가 포함된 현장계측자료의 분석에 대한 고찰

임은상 대한지질공학회 2015 대한지질공학회 학술발표회논문집 Vol.2015 No.1

압전 특성을 이용한 구조물 부재의 응력측정

임은상,김태훈 한국구조물진단유지관리공학회 2007 한국구조물진단유지관리공학회 논문집 Vol.11 No.2

본 연구에서는 압전 특성과 표면전위계를 이용한 응력측정 방법을 제안하였다. 다시 말하면 이 응력측정방법은 압전소자에서 발생한 전위를 표면전위계로 측정하게 하는 방법으로서, 이 표면전위는 구조물 부재의 변형률에 비례한다는 특성을 이용하여, 구조물 부재의 각 위치에서의 발생하는 응력을 변형률로부터 계산할 수 있게 된다. 또한, 구조물 부재의 응력분포를 보다 간편하게 구하기 위해서 비접촉 측정법을 이용한 응력분포 측정 Tape를 제작하였다. 특히, 이 Tape는 균열이나 홈과 같이 이상응력 발생 가능한 위치에서의 σx, σy, τxy의 응력을 측정 뿐만 아니라 국부 응력해석에 활용되었고 그 적용성을 검토하기 위해서 홈이 있는 실험편에 대해서 반복하중 시험결과와 FEM 해석의 결과와 비교 분석하였다. A stress measurement method of structural member using piezoelectric property and electrostatic voltmeter is presented. The electric potentials of the surface of the piezoelectric element, which are proportional to the strain ε on the structural member, are measured by an electrostatic voltmeter during load cycling. The stress σ is calculated by this strain ε. Moreover, a stress distribution measurement tape which can be used for the stress distribution measurement along a specified line on the surface of structural member is developed, and the surface potential was measured by an electric static voltmeter of non-contact type. The applicability of the stress distribution measurement tape is examined through experiments using a notched specimen under cyclic loading. The measured distributions of x, y and xy are compared with those calculated by FEM analysis.

3차원 스캐너를 활용한 댐 안전관리 적용사례

임은상,김재홍,Im, Eun-Sang,Kim, Jae-Hong 한국지반공학회 2009 지반 : 한국지반공학회지 Vol.25 No.10

수자원연구원 지반구조연구소

임은상 한국토목섬유학회 2008 한국토목섬유학회지 Vol.7 No.1

구두발표 : 라인소스 전기장탐사 기술 개발 및 댐에 대한 적용성 연구

임은상,김완영,김재홍,김세진 대한지질공학회 2014 대한지질공학회 학술발표회논문집 Vol.2014 No.-

지중 구조물에 작용하는 측방토압에 대한 성토 재하 속도의 영향

임은상,이강일 한국지반공학회 2004 한국지반공학회논문집 Vol.20 No.7

When an embankment is constructed on soft clay ground, the lateral displacement generally called as lateral flow is generated in the foundation ground. It strongly affects stabilities of structures, such as foundation piles and underground pipes, in and on the foundation ground. The lateral earth pressure induced by the lateral flow is influenced by the magnitude and construction speed of embankment, the geometric conditions and geotechnical characteristics of the embankment, and the foundation ground, and so on. Accurate methods for estimating the lateral earth pressure have not ever been established because the lateral flow of a foundation ground shows very complicated behavior, which is caused by the interaction of shear deformation and volumetric deformation. In this paper, a series of model tests were carried out in order to clarify effects of construction speed of an embankment on the lateral earth pressure in a foundation ground were design. It was found that the magnitude and the distribution of the lateral earth pressure and its change with time are dependent on the construction speed of the embankment. It was found that a mechanism for the lateral earth pressure was generated by excess pore water pressure due to negative dilatancy induced by shear deformation under the different conditions of construction speeds of embankments.

Lateral Earth Pressure Caused by Action on Earth Retaining Wall in Clay Foundation Ground with Consideration of Construction Speed

임은상,이강일,Im Eun-Sang,Lee Kang-Il Korean Geotechnical Society 2004 한국지반공학회논문집 Vol.20 No.7

연약점토지반에 성토 등의 상재하중을 재하하게 되면 측방유동이라고 하는 측방변위가 발생하게 된다. 이 측방유동은 파일기초의 변형, 교대의 이동, 지중매설관의 파괴 등 성토에 인접한 지중구조물에 피해를 가하게 된다. 그렇지만, 측방유동은 체적변형과 전단변형도 동시에 발생할 뿐만 아니라 이 측방유동에 영향을 미치는 인자가 많기 때문에 측방유동에 의해서 발생하는 측방토압의 발생 메커니즘이 아직 명확히 밝혀지지 않았다. 그리고 최근 근접시공 등 기존구조물에 근접해서 공사가 진행되는 경우가 많아 이러한 근접구조물에 어떠한 피해를 가할 것인가 또는 대책공법을 설계하기 위한 설계하중으로서 측방토압을 구해야 하는 필요성이 커지고 있는 것 또한 현실이다. 그러므로 본 연구에서는 성토에 의해서 연약지반에 발생하는 측방토압에 미치는 재하속도의 영향을 조사하기 위해서 실내모형실험을 실시하였다. 그 결과, 측방토압이 삼각형 분포를 이룬다는 것과 재하속도가 빠를수록 측방토압의 최대치가 커지고 부등침하가 커진다는 것을 알 수 있었다. 그리고 이러한 재하속도의 영향은 부의 dilatancy에 의한 과잉간극수압의 발생에 기인한다는 것을 알았다. When an embankment is constructed on soft clay ground, the lateral displacement generally called as lateral flow is generated in the foundation ground. It strongly affects stabilities of structures, such as foundation piles and underground pipes, in and on the foundation ground. The lateral earth pressure induced by the lateral flow is influenced by the magnitude and construction speed of embankment, the geometric conditions and geotechnical characteristics of the embankment, and the foundation ground, and so on. Accurate methods for estimating the lateral earth pressure have not ever been established because the lateral flow of a foundation ground shows very complicated behavior, which is caused by the interaction of shear deformation and volumetric deformation. In this paper, a series of model tests were carried out in order to clarify effects of construction speed of an embankment on the lateral earth pressure in a foundation ground were design. It was found that the magnitude and the distribution of the lateral earth pressure and its change with time are dependent on the construction speed of the embankment. It was found that a mechanism for the lateral earth pressure was generated by excess pore water pressure due to negative dilatancy induced by shear deformation under the different conditions of construction speeds of embankments.