• Journal of the Korean Geotechnical Society
• /
• v.21 no.7
• /
• pp.91-105
• /
• 2005

In this study, the deformation behavior of Daegok dam during the construction was analyzed based on the measurement data and a comparative analysis with foreign CFRD measurements was performed. From measuring settlements of Daegok dam with depth, overall behavior was evaluated to be consistent with measured data of other CFRD dams. In addition, construction modulus, void ratio and shape factor were also evaluated to be major factors in predicting the settlement behavior during construction of CFRD-typed dam from measured data of 38 CFRD-typed dams, and the maximum internal settlement is proportional to the void ratio. From the relationship between the maximum internal settlement and the height of a dam, 26 dams were assessed to have its relative modulus ranging between 0.001 and 0.01. In case of general CFRD, the average modulus of maximum internal settlement to the height of a dam is estimated to be 0.005. In case of a low void ratio, the construction modulus was high with its shape factor below 4. On the other hand, in case of a high void ratio, the relative settlement rate was high with its shape factor more than 4.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.8 no.2
• /
• pp.129-138
• /
• 2008

In case of judging the stability of dike or dam structures which need hydraulic interception, the first thing to do is to examine whether a piping phenomenon occurred or not. Generally, dike or dam structures are constructed while layer compacting is executed, so permeability is likely to be anisotropic- different from each other in hydraulic conductivity in the horizontal direction [$k_x$] and hydraulic conductivity in the vertical direction[$k_y$]. This study looked into exit hydraulic gradient and Seepage velocity by conducting an Seepage analysis subsequent to various hydraulic conductivity ratios[k-ratio = ky / kx] and examined the influence on piping by comparing & examining critical Seepage Velocity based on critical hydraulic gradient in theoretical equation and critical Seepage Velocity in empirical equation. As the research result, it was found that hydraulic conductivity ratio operates as a very important factor in case the stability against piping occurrence is considered with the concept of critical hydraulic gradient, but relatively the hydraulic conductivity ratio is very low in its importance in relation to the concept of critical Seepage Velocity.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.1
• /
• pp.9-18
• /
• 2023

The purpose of this paper is to review the appropriateness of the application method for the value of the damping ratio suggested in the current design standards and evaluation guidelines when evaluating the seismic performance of concrete dams and to suggest improvements. As a result of the study, for the magnitude of the damping ratio in the dynamic elastic analysis, it is necessary to refer to the case of a similar dam in which the magnitude of the earthquake load is similar and the reproducibility of the damping ratio has been verified. Considering this, it is necessary to apply a low damping ratio and consider adding hysteresis damping in case of nonlinear behavior. In addition, since the concrete dam body located on the rock has insignificant radiation attenuation effect, it is not reasonable to increase the damping ratio of the concrete dam body to reflect the radiation damping. Therefore, in order to evaluate the realistic seismic performance of concrete dams, it is necessary to revise the damping ratio-related contents contained in the current dam design standards and evaluation guidelines.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.4
• /
• pp.73-83
• /
• 2006

Seepage analysis through unsaturated zone based on the theory of unsaturated flow is commonly performed to evaluate dam safety. However, the concepts of unsaturated soil behavior have not been transferred into the hands of practicing geotechnical engineers since the problems involving unsaturated soils often have the appearances of being extremely complex. There is variability and uncertainty associated with the unsaturated hydraulic properties that in turn will lead to variability in predicting unsaturated soil behavior such as seepage rate and the pore water pressure distribution. In this paper, measurements of the soil-water characteristic curve and saturated hydraulic conductivity for the core material of dam were conducted. Then, finite element stochastic analysis was used to capture the effect of unsaturated hydraulic properties on the seepage behavior of dam. It is observed that the amount of seepage increases, as the values of unsaturated soil parameters a and n increase. The values of m and p showed opposite trend.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3C
• /
• pp.209-218
• /
• 2006

In this study, stress and deformation of CFRD during its construction and impounding were analyzed and compared with its monitoring results. Moreover, deformation characteristics of CFRD after impounding were evaluated based on the settlement monitoring records of total 23 domestic and foreign CFRDs during construction and impounding. The investigation on the behavior of CFRD indicated that the influence of impounding on its stability was minimal although slight increases in vertical and horizontal stresses and strains were observed. Also, one method was proposed to predict a crest settlement from multi-layer settlements by applying the best fit method. It is expected that the results of this study would provide practical information for the design, construction, and management of CFRD.

• The Journal of Engineering Geology
• /
• v.16 no.1 s.47
• /
• pp.97-107
• /
• 2006

Or this study, prevailing design and construction methods of dam under various unfavorable conditions are summarized. for example, foundation treatment with large scale alluvium site or weathered rock mass, dam constructing techniques with unfavorable topographic conditions are studied for the better understanding of relating engineers. Also, zoning by using weak rocks and sand-gravel fill techniques are summed up.

• 한국지구과학회:학술대회논문집
• /
• 2005.09a
• /
• pp.103-111
• /
• 2005

최근의 급속한 기술 발달을 통해 고전적인 측량 기법을 극복한 3차원 레이저 스캐너를 댐 관리기법의 연구에 적용하였다. 다목적댐과 같은 대규모 댐의 경우, 댐체 변형 특성 파악 및 주변 사면 안정성 연구 등과 관련하여 많은 측량이 필요하지만, 주로 제한된 점 (point)자료를 획득하여 분석하는 데 그쳤다. 본 연구에서는 이를 극복하기 위하여 3차원 레이저 스캐너 장비를 도입하여 조사하고자 하는 대상체에 대해 3차원 디지털 좌표를 다량으로 획득하여 이를 분석 처리함으로써 보다 효율적으로 댐 관리가 이루어지도록 하였다. 본 연구에서는 보강 사면에 대한 변형 특성을 파악하기 위해, 7개월 간격으로 3차원 스캐닝을 통해 좌표 값을 획득하여 이의 분석을 통해 향후 거동에 대해 예측하였다. 분석을 위해 두 시기의 스캐닝 자료를 병합(registration)하여 상대차이를 분석하고, 틀어진 각을 측정하였다. 또한 도면이 존재하지 않는 지자체의 댐에 대한 신속 측량을 3차원 레이저 스캐너로 대체하기 위한 방안에 대해 제시하고, 준공예정인 댐에 대한 스캐닝을 수행하여 설계 도면과의 비교 검토 결과를 분석하였으며, 향후 다양한 이용 방안에 대한 검토와 토론을 제안하고자 한다.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.10a
• /
• pp.23-34
• /
• 2006

In a oo dam at oo city of Gyeongbuk, severe damages have been occurred on lower part of dam due to heavy rainfall for several years. This caused significant impediment for maintaining its original function. This is considered as an excellent case for overall improvement of stability of dam system through successful investigation and construction work. This paper present comprehensive specifications that are generalized and used for securing stability of dams by quoting this example.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.634-639
• /
• 2008

일부 콘크리트댐들의 경우 이상홍수 발생시 상 하류부 수위차가 크지 않은 상태로 월류가 발생하는 특징이 있으며, 치수능력 증대사업을 수행하여 안전성을 확보하기에는 지리적, 경제적인 문제로 어려움이 많아 현실적인 대책 수립이 어려우므로 월류가 발생한 상태에서도 안전성이 확보될 수 있는가에 대한 검토가 필요하다. 한국시설안전공단(2007)에서는 기존 댐의 수문학적 안전성 평가를 필댐과 콘크리트댐으로 구분 적용할 필요성과, 콘크리트댐의 경우 상태에 따라 일부 월류를 허용할 수 있는 방안에 대한 연구를 수행하였으며, 본 연구는 콘크리트 댐의 구조적 안전성 검토의 평가방법으로 수행하게 되었다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2005.03a
• /
• pp.26-33
• /
• 2005

In this paper, a computational model for nonlinear crack damage analysis of concrete gravity dam-foundation boundary region subjected to earthquake loading is suggested. An enhanced model based on the Lee-Fenves plastic-damage model is used as the inelastic material model for a concrete dam structure and rock foundation. The suggested model is implemented numerically and used for computational earthquake simulation of Koyna dam, which was severly damaged from the strong earthquake in 1967. From the numerical result it is demonstrated that the suggested computational model can realistically represent crack initiation and propagation in the dam-foundation boundary region.