• 한국농공학회논문집
• /
• 제61권1호
• /
• pp.131-144
• /
• 2019

The purpose of study was to determine the hygrophyte index of each plant(HIP) considering the moisture environment condition (MEC) of the native plants on the downstream slope of the fill dam and evaluate its applicability which to develop a method to search for leaks and saturated zones of the fill dam for status evaluation of precision safety diagnosis. The HIP was weighted average and consisted of 19 ranks. The weighted average was calculated according to the following three procedures: First, the linear assumption was made according to the actual habitat environmental conditions, the second one was weighted to 10% of the optimal habitat condition, and finally the average value of the distribution range values. The Hygrophyte index of vegetation at each plot (HIV) was obtained from the Sinheung reservoir (Yesan-gun, Chungcheongnam-do) using the results of vegetation survey of the Sinheung reservoir with precision safety diagnosis and suggested the use of the hygrophyte index of the cultivated vegetation. The average HIP range of plant species that emerged in 50 survey sites on the downstream slope of the Sinheung reservoir is 2.99 to 3.56. The coefficient of variation showed a large difference depending on the appearance of the leakage indicator plant(LIP) species. The range of HIV is 2.80 to 4.26, the mean value is 3.37, standard deviation is 0.37 and the coefficient of variation is 9.7%. As a result, the value of the coefficient of variation showed a large difference depending on the appearance of the plant species.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.1025-1028
• /
• 2009

Earth and rock fill dam is our typical dam because of their inherent flexibility and adaptability to various fundation conditions. In order to secure structural safety, rockfill materials are used angular particles obtained by blasting parent rock or rounded particles collected from river beds. Concrete-faces rockfill dams(CFRD) and Concrete-faces gravelfill dams(CFGD) have become popular in the last 20 years as s result of their good performance and low cost compared with the rockfill dam. These Dams are also constructed by the materials. 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 stress-strain and strength properties can be adequately define. However the stress-strain properties of rockfill are difficult to determine because the properties are affected by such factors as particle grading, size and shape of particles, stress conditions, and particle crushing. In our study, testing of the behavior of the rockfill materials are essential prerequisites to the realistic analysis and design of the CFGD. This paper deals with laboratory testing of particle crushing among the study.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 춘계 학술발표회
• /
• pp.278-287
• /
• 2009

This thesis studied effect of zoning on seepage flow in concrete faced gravel-fill dam (CFGD) designed to have selected main rockfill or gravel-fill zone, Zone 3Bs with higher permeability to enhance the safety against accidental water infiltration into the dam. For this purpose, centrifuge model tests with two cases, with and without Zone 3Bs, were performed in order to investigate the necessity and the function of Zone 3Bs. Model dams were made by soil samples with modified coefficients of permeability and concrete faced slab was simulated with aluminum alloy. Water infiltration was simulated by rising water table over cracks on the facing. Behaviors of model dams were measured by LVDTs, strain gages, pore water pressures and cameras. Form the results of centrifuge tests, it was found out that the Zone 3Bs acts as a protection of main gravel-fill zone by inducing flow paths for infiltrated water into it as well as by draining off the infiltrated water out of the dam in a short time.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
• /
• pp.3-14
• /
• 1999

The Hyogoken-Nambu Earthquake of January 17, 1995 inflicted severe damage in the Hanshin and Awaji areas such as has never been seen in Japan in recent years. The safety inspections of the dams conducted in the area by site offices and dam experts immediately after the earthquake showed that there was no damage affecting the safety of the dams although slight damage was observed in several dams. The investigation also revealed that the peak accelerations at dam sites were much smaller than those at soil sites. The Ministry of construction organized the Committee on Evaluattion of Earthquake Resistance of Dams after the earthquake. The Committee confirmed through dynamic analysis that the dams designed in accordance with the present design criteria in Japan are safe under the magnitude of shaking that occurred close the source fault of the Hyogoken-Nambu Earthquake.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.1037-1040
• /
• 2009

Using much most electricity electric resistivity survey by nondestructiveness inquiry enforcement design of country base equipment business and facilities preservation administration dimension electric resistivity survey sends and cause much effects in survey believability by electricity medium of survey personality survey contiguity that grasp base special quality by potential difference flowing current artificially in base. Is item that enforce in most in-suite although when make electric resistivity survey until present, electricity medium or effect research by electricity origination was gone much. There is shortcoming that must be difficult to know correct underground utilities establishment state in-suite in this research and do comparison examination running parallel drilling investigation to heighten believability of electric resistivity survey. Did to dam that censure data that regulate grading from construction and is censure construction which can know correctly interior base situation comparatively to electricity medium of interior and electricity eruption won of contiguity and base condition (base rock).

• 산업기술연구
• /
• 제28권B호
• /
• pp.39-45
• /
• 2008

Temperature variation according to space and time on the inner parts of engineering constructions(e.g.: dam, slope) can be a basic information for diagnosing their safety problem. In general, as constructions become superannuated, structural deformation(e.g.: cracks, defects) could be occurred by various factors. Seepage or leakage of water through these cracks or defects in old dams will directly cause temperature anomaly. Groundwater level also can be easily observed by abrupt change of temperature on the level. This study shows that the position of seepage or leakage in dam body can be detected by multi-channel temperature monitoring using thermal line sensor. For this, diverse temperature monitoring experiments for a leakage physical model were performed in the laboratory. In field application of an old earth fill dam, temperature variations for water depth and for inner parts of boreholes located at downstream slope were measured. Temperature monitoring results for a long time at the bottom of downstream slope of the dam showed the possibility that temperature monitoring can provide the synthetic information about flowing path and quantity of seepage of leakage in dam body.

• 국제학술발표논문집
• /
• The 6th International Conference on Construction Engineering and Project Management
• /
• pp.604-605
• /
• 2015

To secure quality of dam construction needs appropriate construction duration. Tight construction schedule may have negative influence on infrastructure quality, work safety and maintenance cost. It is necessary to reflect proper construction duration in the planning phase. There have been standards for estimating construction duration of building and industrial complex development but dam construction have not. In order to estimate construction duration of CFRD, feasible study reports and design reports were analyzed to acquire available information. After that, considering on construction duration methods such as comparison with similar cases, approximate estimating formula, approximate quantity assumption were adapted to Critical Path items. Hence, this study present framework for construction duration estimating of CFRD in the planning phase. This framework can be applied other types of dam along the same line.

• 한국지진공학회논문집
• /
• 제18권4호
• /
• pp.161-170
• /
• 2014

Newmark-type deformation analysis has rarely been done in Korea due to the popularity of simple pseudo-static limit equilibrium analysis and detailed time-history FE/FD dynamic analysis. However, the Korean seismic dam design code updated in 2011 prescribes Newmark-type deformation analysis as a major dynamic analysis method for the seismic evaluation of fill dams. In addition, a design PGA for dynamic analysis is significantly increased in the code. This paper aims to study the seismic evaluation of four existing large fill dams through advanced FEM/Newmark-type deformation analyses for the artificial earthquake time histories with the design PGA of 0.22g. Dynamic soil properties obtained from in-situ geo-physical surveys are applied as input parameters. For the FEM/Newmark analyses, sensitivity analyses are performed to study the effects of input PGA and $G_{max}$ of shell zone on the Newmark deformation. As a result, in terms of deformation, four fill dams are proved to be reasonably safe under the PGA of 0.22g with yield coefficients of 0.136 to 0.187, which are highly resistant for extreme events. Sensitivity analysis as a function of PGA shows that $PGA_{30cm}$ (a limiting PGA to cause the 30 cm of Newmark permanent displacement on the critical slip surface) is a good indicator for seismic safety check. CFRD shows a higher seismic resistance than ECRD. Another sensitivity analysis shows that $G_{max}$ per depth does not significantly affect the site response characteristics, however lower $G_{max}$ profile causes larger Newmark deformation. Through this study, it is proved that the amplification of ground motion within the sliding mass and the location of critical slip surface are the dominant factors governing permanent displacements.

• 지질공학
• /
• 제15권1호
• /
• pp.77-86
• /
• 2005

CFRD(Concrete fared Rockfill Dam)는 기존의 중심코어형 락필댐과 대별되는 우수한 구조적, 재료적 특성으로 현재 가장 널리 활용되는 댐 형식이다. 본 고에서는 그동안 이루어져온 기술의 축적을 바탕으로 CFRD의 설계와 시공에 있어 최근에 부각된 최신 기술들을 정리하여 향후 활용에 도움을 줄 수 있도록 하였다. 특별히 본 고에서는 최근 경험을 바탕으로 실무에서 적용되고 있는 연약한 암을 이용한 댐체 축조 사례, 대단히 큰 입경의 락필 재 대신 도입된 sand-gravel fill 댐에 대한 경험, plinth와face slab를 연결하기 위해 새롭게 채택된 연결 슬래브공법, 기존 댐의 증고사례, 역침투 현상, 댐 하류의 환경친화죤, 차수벽 슬래브의 두께와 철근비의 변화 추이, 충적층 기초의 처리, 최근 적용되기 시작한 curb element 공법등에 대한 간략한 기술적 동향을 고찰하여 관련 기술자들의 이해를 돕고자 하였다.

• 지구물리
• /
• 제6권3호
• /
• pp.165-177
• /
• 2003

필댐의 안정성 해석에 있어서 누수와 내부침식은 매우 중요한 평가의 한 부분이다 연구대상 지역의 필댐은 내부침식으로 추정되는 댐 상부의 공동발생 및 과대 누수량으로 문제가 발생하여, CGS(compaction grouting system)으로 보강공사를 수행하였으며, 본 보강방법은 주입재료 및 주입압력이 중요한 변수로 작용을 한다. 본 연구에서는 CGS 보강이 필댐의 안정성에 미치는 영향을 CGS보강 전후에 지구물리탐사를 수행하여 해석하였다. 본 조사에 적용된 방법에는 전기비저항탐사, 탄성파 굴절법탐사, GPR탐사, HFMT탐사 등이 적용되었다. 조사결과 CGS 보강으로 댐의 전제척인 거동에 많은 영향을 준 것으로 나타났으며, 주입압력이 과대하여 댐 중심코아에 많은 변위가 발생된 것을 확인할 수 있었다.