사석마운드 다짐에 의한 중력식 안벽 내진성능 개선 연구

사석마운드 다짐에 의한 중력식 안벽 내진성능 개선 연구. 2004. 12.. 연구기관 : 한국해양연구원. 해 양 수 산 부 M IN IS T R Y O F M A R IT IM E A F F A IR S & F IS H E R IE S.

제. 출. 문. 해양수산부장관 귀하. 본 보고서를 “사석마운드 다짐에 의한 중력식 안벽 내진성능 개선 연구” 과제의 최종보고서로 제출합니다.. 2004. 12.. 주관연구기관명. :. 한 국 해 양 연 구 원. 주관연구책임자. :. 장. 연. :. 박우선, 권오순, 한상훈,. 구. 원. 인. 성. 김동현, 정원무, 안희도, 이광수, 김경아, 박은경, 이보람, 안순영, 고은선 위탁연구기관명. :. 서. 위탁연구책임자. :. 김. 울. 대 명. 학. 교 모.

요 약 문. I. 제 목. 사석마운드 다짐에 의한 중력식 안벽 내진성능 개선 연구. II. 연구개발의 목적 및 필요성. 중력식 안벽이나 방파제 구조물에서 사석마운드나 뒷채움 지반의 다짐정도가 중력식 구 조물의 정적인 거동 및 동적인 거동에 큰 영향을 미친다는 것은 어느 정도 알려진 사실이 다.. 하지만, 국내의 중력식 케이슨 안벽이나 케이슨 방파제의 경우 사석마운드를 다져서. 시공하도록 되어 있지 않아 향후 정적인 성능 개선 이외에도 동적 내진성능 향상을 위해 이에 대한 개선의 필요성이 제기되고 있다. 본 사업의 목적은 대형 실내실험 결과를 기초 로 하여 상사법칙을 적용한 중력식 안벽에 대한 대형 진동대 모형실험 및 수치모형실험을 통하여 사석마운드의 다짐정도가 중력식 안벽의 내진성능에 미치는 영향을 정성적․정량 적으로 분석함으로써 향후 중력식 안벽의 내진설계 및 시공에 활용하고자 하는 것이다.. III. 연구개발의 내용 및 범위 본 사업의 연구내용은 크게 3가지로 구분할 수 있다.. 첫 번째는 대형 직접전단시험과. 공진주 실험 등의 실내실험을 통해 사석마운드 및 뒷채움 재료로 각각 활용되는 사석과 모래의 다양한 공학적 특징, 즉 전단특성과 변형특성을 상대밀도에 따라 비교 분석하는 것 이고, 두 번째는 중력식 방파제 구조물과 안벽 구조물을 대상으로 대형 진동대실험을 통해 상대밀도에 따른 내진성능을 서로 비교하는 것이다. 그리고, 세 번째는 실제 규모의 구조 물에 대한 수치모형실험을 수행하여 진동대실험에서 구현하지 못한 다양한 영향변수 연구 뿐만 아니라 실제 거동예측을 확인하고자 하는 것이다.. - i -.

IV. 연구개발결과 대형 진동대 실험에서 활용한 사석(최대 직경 25mm)을 비롯하여 다양한 입경에 대한 대형 직접전단시험 수행하여 정적인 강도특성에 미치는 상대밀도의 영향을 확인하였고, 수 치모형실험 활용을 목적으로 뒷채움 모래에 대한 공진주 시험을 통해 동적특성(전단탄성 계수 및 감쇠비)을 파악하였다.. 그리고, 고베항의 1/14.5 크기의 대형 진동대실험을 실제. 설계지진특성을 고려한 인공지진을 사용하여 수행한 결과, 방파제 모형과 안벽 모형 모두 상대밀도가 커짐에 따라, 즉 사석마운드의 다짐정도가 증가함에 따라 내진성능이 뛰어나다 는 사실을 확인하였다.. 이러한 경향은 진동대 실험 단면에 대한 수치모형실험을 통해 확. 인하였고, 이에 근거한 수치모형실험을 통해 실제 규모에 대한 다양한 변수연구를 수행하 였다.. V. 연구개발결과의 활용계획 연구를 통해 얻어지는 결과는 향후 항만 및 어항 시설물의 설계 및 시공 기준에 활용되 어 사석마운드를 활용하는 항만구조물에 대한 설계시 안정성과 경제성 제고에 기여할 수 있을 것으로 기대되고, 또한 사석이 사용되는 다양한 토목구조물(경사 사석식 가물막이, 댐 등)의 내진성능을 향상시키는 데에도 직접적으로 활용될 수 있을 것으로 판단된다. 그 리고, 중력식 구조물의 시공시 사석마운드를 다지기 위한 기술이 도입되고, 실제 시공사례 가 증가하면서 보다 효율적인 다짐기법이 국내 자체 기술로 개발되는 계기가 될 것으로 기대된다.. VI. 연구개발목표 달성도 및 대외기여도 본 연구의 주된 목표인 사석마운드의 다짐에 의한 중력식 안벽 구조물의 내진성능 검토 는 실내실험과 대형 진동대실험, 그리고 수치모형실험을 통해 모두 당초 계획한 바대로 100% 달성하였다.. 도출된 연구 결과는 향후 항만 및 어항의 설계기준에 활용될 수 있을. 것으로 기대되고, 이로 인해 보다 경제적이고도 안전적인 중력식 구조물 설계 및 시공에 기여할 수 있을 것으로 판단된다.. - ii -.

SUMMARY 1. Title Improvement of seismic performance of gravity type quay wall due to compaction of the rubble mound. 2. Objectives and Necessities For a gravity type quay wall or breakwater, it has been known that the compaction of rubble mound or backfill is highly correlated to the static behaviour of the structure. However, the necessity of the compaction is being emphasized for improvement of seismic performance of the caisson type structure as well as static efficiency.. The object of this. research is to evaluate the effect of the relative density of the rubble mound on the seismic performance of the gravity type structure by using shaking table test and numerical simulations, which adopt the similitude law based on large scale of laboratory test results.. 3. Contents and Scope The three main works were focused to this research. At first, the strength and deformation characteristics were investigated regarding to the particle size and relative density and particle distribution etc. by using large scale direct shear test and resonant column test as well as index properties tests. Secondly, the seismic performance was compared each other with relative density for gravity type breakwater and quay wall structure. Finally, the parametric studies considering various conditions, which couldn't be conducted at shaking table tests, were carried out using numerical simulations.. - iii -.

4. Results and Discussions The effect of relative density on the strength characteristics was investigated from large scale of direct shear tests with gravels (maximum particle diameter 25mm) utilized in shaking table tests. The resonant column tests were also conducted at the laboratory for the purpose of obtaining dynamic characteristics such as shear modulus and damping ratio, which are needed at numerical simulations. From the results of shaking table tests, which were conducted by adopting an artificial earthquake with actual design earthquake characteristics, with a scale of 1/14.5 of Kobe port in Japan, it was verified that the seismic performance of the gravity type structures increase as the relative density and degree of compaction increase.. 5. Practical Application of the Results The results in this research are expected to contribute to the economical and safe design of gravity type structures with rubble mound by applying to the design and construction specification of harbor and fishery port facilities. Furthermore, the researches could be directly applied to various structures including mound type cofferdam, and to the development of the or own compaction technology of rubble mound.. 6. Achievements and Contribution The objectives of this project in this year, i.e., the investigation of the seismic performance of gravity type quay wall structure due to compaction of rubble mound, were completely achieved as scheduled by performing the laboratory tests, large scale shaking table test and numerical simulations.. The results of this research could be utilized at the design and. construction specification of harbor and fishery port facilities, therefore, contribute to the safe and economical design and construction of port and harbor structures.. - iv -.

목. 차. 제 1 장 서론 ·········································································································································1 제 1 절 연구의 배경 ························································································································1 제 2 절 연구의 목적 ························································································································2 제 3 절 연구수행내용 ······················································································································2 제 4 절 연구의 기대효과 및 활용방안 ·························································································3 1. 기대효과 ····································································································································3 2. 활용방안 ······································································································································3. 제 2 장 기존문헌연구 ·························································································································5 제 1 절 사석 재료의 전단특성 ·······································································································5 1. 개요 ··············································································································································5 2. 국내의 연구 상황 ······················································································································6 제 2 절 사석마운드 다짐공법 ········································································································8 1. 개요 ··············································································································································8 2. 국내 적용 사례 ··························································································································9 3. 국외 적용 사례 ························································································································10. 제 3 장 실내시험 ·······························································································································11 제 1 절 시료의 강도정수 산정을 위한 대형직접전단시험 ·····················································11 1. 시험 개요 ··································································································································11 2. 시험 장치의 구성 ····················································································································12 3. 시험 방법 ··································································································································13 가. 시료의 종류 및 시험조건 ··································································································13 나. 시험 절차 ······························································································································15 4. 해석방법 ····································································································································15 가. 시료의 내부 마찰각 ············································································································15. - v -.

나. 탄성계수 ································································································································16 5. 시험결과 및 고찰 ····················································································································16 가. 전단응력-변형률 곡선 ·······································································································16 나. 내부마찰각 ····························································································································20 다. 할선탄성계수 (G50) ·············································································································27 제 2 절 동적 물성치 평가를 위한 공진주 시험 ·······································································28 1. 시험 개요 ··································································································································28 2. 시험 장치의 구성 ····················································································································29 가. 구속 시스템(Confinement System) ················································································29 나. 드라이브 시스템(Drive System) ·····················································································30 다. 높이 변화 측정 시스템(Height Change Monitoring System) ·································30 라. 움직임 계측 시스템(Motion Monitoring System) ······················································30 마. 시험 장치의 가동 ················································································································31 3. 시험 방법 ··································································································································32 가. 시료의 기본 물성 및 성형 ································································································32 나. 시험 절차 ······························································································································32 다. 시험의 조건 ··························································································································33 4. 해석방법 ····································································································································35 가. 전단탄성계수 ························································································································35 나. 전단변형률 ····························································································································36 다. 감쇠비 ····································································································································38 라. 비선형 응력-변형율 모델 ·································································································40 5. 시험결과 및 고찰 ····················································································································42 가. 전단탄성계수(Shear modulus, G) ···················································································42 나. 정규화 전단탄성계수(Normalized shear modulus, G/Gmax) ···································44 다. 감쇠비(damping ratio, D) ·································································································46 라. 비선형 응력-변형률 모델 ·································································································48 마. 통계적 결과와의 비교 ········································································································53 바. 상대밀도에 따른 동적 물성치의 변화 ············································································57 제 3 절 요약 및 결론 ····················································································································59 1. 대형직접전단시험 ····················································································································59. - vi -.