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.

Life cycle carbon dioxide emissions for fill dams

Noh, Sookack,Son, Younghwan,Park, Jaesung Elsevier 2018 Journal of cleaner production Vol.201 No.-

<P><B>Abstract</B></P> <P>The construction industry including infrastructure construction, affects the environment due to the use of a considerable amount of resources and energy. The management of the environmental effect of dams for agricultural reservoirs is especially important in South Korea because of their large scale and nationwide distribution. The objective of this study is to propose an assessment method for evaluating life cycle carbon dioxide emissions associated with fill dams and to characterize carbon dioxide emissions to use in effectively addressing the environmental concerns for infrastructures. A total of four dams were selected for the research, and the material production, use of equipment and transportation were considered as the causes of carbon dioxide emissions at the dams. The effective life cycle of a fill dam was assumed to be 100 years. The results of the research indicated that the total amount of carbon dioxide emissions were different for each dam according to their characteristics, and the results showed that the dam size is the primary cause. In addition, the carbon dioxide emissions increased as the period of use increased, and a rapid increase was indicated in 40–50 years interval of the dams’ use periods because the repair activities were concentrated in those years. Materials were the biggest contributor in the amount of total carbon dioxide emissions at all four sites and the ratio of carbon dioxide emissions caused by materials was higher than any other factors in most processes. There was little difference in the proportion of carbon dioxide emissions for each process in the total carbon dioxide emissions for the four sites. Most carbon dioxide was emitted during repair activities at the two largest dams. Activities associated with the construction process was the major source of carbon dioxide emissions at the two other dams. This difference in process carbon dioxide emissions was the result of the difference in the construction scale for the embankment elevation. The assessment method that has been proposed in this study reflects the characteristics of fill dams, and the result of estimating carbon dioxide emissions indicates that we are able to reduce carbon dioxide emissions in the life cycle of fill dams by selecting the construction materials and the repair methods with a low carbon dioxide emissions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We evaluated and characterized life cycle CO<SUB>2</SUB> emissions for fill dams. </LI> <LI> Material consumption was the major cause of CO<SUB>2</SUB> emissions in life cycle of fill dams. </LI> <LI> Most CO<SUB>2</SUB> were emitted during a construction and a maintenance stage in fill dams. </LI> <LI> Life cycle CO<SUB>2</SUB> emissions for fill dams were influenced by their scale, mainly. </LI> </UL> </P>

콤팩션 그라우팅에 의한 흙댐의 누수복원 공사효과 분석

천병식,정하익,이용재 한국지반공학회 2006 한국지반공학회논문집 Vol.22 No.11

The sinkhole and leakage in dam core were detected at one of earth fill dams in Korea. The damage areas in the core of the dam were repaired by compaction grouting method. This study is to evaluate compaction grouting activity by in-situ and laboratory experiments before, during and after the remedial work. The intensive site investigation and geophysical survey were conducted during and after the compaction grouting work. The compaction grouting work was carried out for the damaged dam core between June 16 and August 24, 2000. The leakage reduction generally occurred in the core of the dam after the remedial work. The use of compaction grouting was considered the proper countermeasures for repairing the damaged dam. It shows that the loose or voided zones have been properly filled and the leakage has been reduced by about 96% of that before the treatment of the remedial work performed at dam core by compaction grouting.

국내 FILL DAM에 대한 BREACH 모형의 적용성 검토

송주일,원진영,임창수,윤세의 한국방재학회 2012 한국방재학회논문집 Vol.12 No.1

This study examined how the two models such as DAMBRK and BREACH that can calculate the breach outflow depending on time steps affect the simulation result. Furthermore, as a result of the examination, a resonable methodology was suggested to build up the emergency action plan (EAP). The DAMBRK and the BREACH models were used to calculate the breach outflow from the Mantaro dam, and the outflow hydrograph estimated by BREACH model was similar to the measured one. Dam crest wide was an important factor for peak flow time. In cases of An-dong dam and upper and lower Mu-ju pumped-storage dam,when the dam crest wide was not considered, the peak flow occurred early, and discharge decreased, so that flooded area decreased. To obtain the breach outflow hydrograph similar to BREACH model simulate, the DAMBRK model could be corrected by adjusting parameters; however, it still includes many uncertainties. Therefore, for fill dam, in order to estimate the hydrograph under the situation of the dam break, the BREACH model is more resonable. Using the hydrograph simulated by BREACH model as input for flood routing could give a higher accuracy than only using DAMBRK model. 본 연구에서는 댐 붕괴 상황 시 시간변화에 따른 유출해석이 가능한 DAMBRK와 BREACH모형의 물리적 해석 방법 차이가 모의 결과에 어떠한 영향을 주는지를 검토하였다. 또한 이를 통해 보다 합리적인 비상대처계획 수립 방안을 제시하고자 하였다. 이를 위해 우선 실측된 유출수문곡선이 존재하는 Mantaro댐에 두 모형을 적용하였다. 적용결과 BREACH모형이 실측값과 유사하게 모의를 하였고, 댐 마루폭의 고려여부가 첨두유출발생 시간에 지배적인 영향을 미치고 있음을 알 수 있었다. 안동댐, 무주양수 상·하부댐에 대한 모의 결과에서도 댐 마루폭을 고려하지 않은 경우의 첨두유출 발생은 댐 마루폭을 고려하였을때 보다 이른 시간에 발생하였고 첨두유출량은 감소하였으며, 감소된 첨두유출량으로 인해서 홍수범람구역 면적이 작게 산정되었다. DAMBRK모형의 매개변수를 임의로 조정하는 경우 BREACH모형의 모의결과와 유사한 유출수문곡선의 산정이 가능함을확인하였다. 하지만 매개변수를 가정하는 과정에 여전히 불확실성을 내포하고 있다. 따라서 fill dam의 경우에는 붕괴유출수문곡선 산정 시 BREACH 모형을 이용하고, 이를 DAMBRK 모형에 적용하여 하도추적을 하는 방법으로 댐 붕괴 모의를 하는것이 보다 높은 신뢰성을 확보하는데 도움을 줄 수 있을 것으로 판단된다.

여유고만으로 추정된 국내 재해위험 저수지의 지진시 파괴확률

하익수,이수권,임정열,정영훈 대한토목학회 2016 대한토목학회논문집 Vol.36 No.3

The objective of this study is to illustrate the methods and procedures for estimating the failure probability of small fill dams subjected to earthquake events and to estimate the seismic failure probability of the Korean disaster risk fill dams where geotechnical information is not available. In this study, first of all, seismic failure probabilities of 7 disaster risk small fill dams, where geotechnical information is available, were evaluated using event tree analysis. Also, the methods and procedures for evaluating probabilities are illustrated. The relationship between dam height and freeboard for 84 disaster risk small dams, for which the safety diagnosis reports are available, was examined. This relationship was associated with the failure computation equation contained in the toolbox of US Army corps of engineers. From this association, the dam height-freeborard critical curve, which represents ‘zero’ failure probability, was derived. The seismic failure probability of the Korean disaster risk fill dams was estimated using the critical curve and the failure probabilities computed for 7 small dams. 본 연구의 목적은 소규모 필댐의 지진시 파괴확률을 산정하는 방법과 절차를 예시하고, 지반공학적 정보가 부족한 국내 재해위험 저수지의 지진시 파괴확률을 추정하는 것이다. 이를 위하여, 국내 재해위험 저수지로 지정된 저수지 중 지반공학적인 정보를 얻을 수 있는 7개 저수지에 대해사건수 분석 기법을 적용하여 지진에 대한 파괴확률을 평가하였으며, 그 방법 및 절차를 예시하였다. 안전진단보고서를 확보한 84개 재해위험저수지의 댐높이와 여유고와의 관계를 검토하였고, 미공병단 평가도구로 이용되는 파괴확률 산정식을 이러한 댐높이와 여유고와의 관계에 연관시켰다. 이러한 연관관계로부터, 지진시 파괴확률이 ‘0’이 되는 댐높이-여유고 임계곡선을 도출하였고, 이러한 임계곡선과 7개 저수지에 대해 산정한 지진시 파괴확률로부터 물성확보가 어려운 국내 재해위험 저수지의 개략적인 지진에 대한 파괴확률을 추정하였다.

노후댐 보수보강을 위한 침투그라우팅 효과 분석

이동범 ( Dong-beom Lee ),임희대 ( Heui-dae Lim ),송영수 ( Young-su Song ) 대한지질공학회 2018 지질공학 Vol.28 No.2

10년 전부터 댐 건설에 대한 사회적 비판이 제기됨에 따라 댐 공사를 통해 새로운 수자원을 확보하기가 어려워졌기 때문에 기존 댐에 대한 검토가 필요하게 되었다. 이에 따라, 계획, 시공 및 관리 등의 접근 방식은 댐 보수 및 보강과 관련하여 이미 확보된 기술을 활용하여 실시되었다. 이러한 보수와 보강의 결과로, 다수의 댐에서 침투 그라우팅이 수행되었으나, 현재까지 기술의 정립이 미흡한 실정이고, 국내외적으로 발표된 논문도 극히 드문 편이다. 본 논문에서는 YC댐에 대한 저압 침투그라우팅 보강 기술을 상세하게 분석하였다. 결과적으로 침투그라우팅은 YC댐과 같이 코어형 필댐의 차수성 개선에 효과적으로 적용될 수 있음을 확인하였다. 그리고, 주입기준과 관련하여 경험적으로 증명된 침투그라우팅의 기술적 상세들을 제시하였다. 본 연구를 통한 필댐 침투그라우팅 기술의 구체적인 분석자료들은 향후 필댐 및 저수지 보수보강에 있어 유용한 자료로 활용 가능할 것으로 판단된다. As it has become difficult to secure new water resources through dam construction due to the critical social public opinions on dam construction from 10 years ago, it is necessary to review the existing water resources through the review of existing dams. Accordingly, access methods, such as planning, construction and management, were carried out using technologies already accumulated in relation to the repair and reinforcement of the dam. As a result of the repair and reinforcement, permeation grouting has been performed in many dams, but the establishment of the technology is insufficient so far, and the published paper at home and abroad is extremely rare. In this thesis, low-pressure penetration and grouting reinforcement technologies for the YC dam are analyzed in detail. As a result, penetration grouting has shown that it can be effectively applied to the improvement in the constallability of the core fill-like a YC dam. In addition, the technical details of the experience-proven penetration grouting are given in relation to the injection criteria. It is deemed that the specific analysis data of the Fill Dam penetration grouting technology through this study can be used as useful data for strengthening the repair of Fill Dam and reservoir.

물성치 변동성에 의한 불확실성이 고려된 국내 필댐 사력부를 위한 전단파 속도 주상도 모델

박형춘 한국지반공학회 2019 한국지반공학회논문집 Vol.35 No.2

There always exist the spatial variations of material properties such as a shear wave velocity in a dam and between same type dams. These uncertainties cause those in evaluation of a shear wave velocity profile of a dam and should be considered in determining the shear wave velocity profile for a rockfill zone of a fill dam. In this paper, these uncertainties of a shear wave velocity in the rockfill zone of the fill dam in Korea are evaluated. And the shear wave velocity profile model considering these uncertainties in rockfillzone is proposed using the method based on Harmonic wavelet transform. The proposed shear wave velocity profile model is compared with Sawada-Takahashi model widely used for evaluation of a shear wave velocity profile of a rockfill zone of fill dams.

중심코어형 필댐의 코어재 현장 물성에 대한 통계학적 분석

박동순,오제헌 한국방재학회 2016 한국방재학회논문집 Vol.16 No.3

For the safety evaluation of aged cored fill dams, it is essential to obtain in-situ engineering properties of core zone. However, material properties of aged dam cores have been rarely reported or published. In this study, comprehensive geotechnical investigation and laboratory testing schemes were conducted by no-water borehole drilling and sampling through the dam cores of 13 earth cored fill dams. As a result, (N1)60 distribution by SPT were plotted to normalize confining pressure dependency and to identify stiffnesses of compacted core layers. After statistical processing, we proposed the median, upper and lower bound distribution of both fundamental soil properties (such as gradation, water content, specific gravity, unit weight, liquid limit, and plasticity index) and mechanical properties (such as permeability, strength parameters, and consolidation characteristics) for in-situ aged dam cores. Detail features of each parameter are discussed for characteristic dams. The results are believed to be contributable to the safety evaluation of aged cored fill dams with insufficient information regarding in-situ material properties, and to the classification of the potential hazard of cores. 노후화되어 가는 기존 코어형 필댐의 안전성 평가에서 코어존의 현장 물성 획득은 필수적이나, 현재까지 문헌자료 또는 지반조사에 의한 실험 자료는 매우 부족한 실정이다. 본 연구에서는 국내 13개 중심코어형 필댐을 대상으로 무수보링 직접시추 방법에 의한 광범위한 코어재 지반조사 및 실내시험을 수행하였다. 표준관입시험 결과, 구속압 의존성을 정규화하고 코어재의 강성 파악을 위해 (N1)60 분포를 통계적으로 제시하였다. 시험 성과를 분석하여 축조 후 시간경과에 따른 필댐 현장 코어재에 대한 기본물성(입도, 함수비, 비중, 단위중량, 액소성한계) 및 역학적 물성(투수계수, 강도정수, 압밀특성) 통계 모델을 평균과 상하한 범위로 제시하였다. 각각의 물성에 대한 댐별 특성을 토의하였다. 본 성과는 물성 정보가 불충분한 기존 코어형 필댐의 안전성 평가에 유용하게 활용 가능하며, 댐체 코어층의 위해도 분류에도 효과적일 것으로 판단된다.

Effectiveness of Leakage Control after Application of Permeation Grouting to Earth Fill Dam

Byung Sik Chun,Yong Jae Lee,Ha Ik Chung KOREAN SOCIETY OF CIVIL ENGINEERS 2006 KSCE Journal of Civil Engineering Vol.10 No.6

<P>This study describes the effectiveness of permeation grouting applied for remedial works of the defected earth fill dam located in Korea. A small cavity was discovered in some part on the crest of the dam when the reservoir water level rose to 150m after the first impounding in June 1998. Although the cavity was backfilled with gravel and rubble, collapsing of the sinkhole was continuously taking place. Thus, a comprehensive investigation such as electric resistivity test, borehole test, tracer test et al. was planed and executed to detect the leakage and the sinkhole developed in the earth dam. Based on the results of the investigation, the compaction grouting program was carried out in June 2000. Observations made after the completion of the compaction grouting showed that the leakage generally decreased below the reservoir of elevation 138m. However, the leakage and turbidity through the embankment increased over the elevation 138m. The possibility of weakness formation in dam body was arisen around the water elevation 145~150 m. Thus, the permeation grouting method after compaction grouting application was applied for additional remedial work of the defected dam to establish the permanent safety. Permeation grouting method, combining with fracture grouting, was recommended for the core zones. Permeation grouting with either particulate or chemical grouts is utilized to give cohesion or to reduce the permeability soils. Portlant cement grouting was performed first and micro cement was then grouted through the upstream portion of the dam. After the permeation grouting consecution, seepage quantity trend of the earth-fill dam was stable and dependent on the reservoir level, and defected dam was effectively repaired. The permeation grouting application significantly reduced leakage to 4~50 ㎥/day compared with initial damaged stage of 2500 ㎥/day and compaction grouting of 800 ㎥/day application. The seepage quantity significantly reduced from 640 ㎥/day to 4.1 ㎥/day after applying the permeation grouting method, and the leakage decreased from 2,500 ㎥/day to 800 ㎥/day.</P>

The Effect of Remedial Works to Control the Leakage Problem in Earth Fill Dam by Compaction Grouting

천병식,이용재,정하익,Chun, Byung-Sik,Lee, Yong-Jae,Chung, Ha-Ik Korean Geotechnical Society 2006 한국지반공학회논문집 Vol.22 No.11

The sinkhole and leakage in dam core were detected at one of earth fill dams in Korea. The damage areas in the core of the dam were repaired by compaction grouting method. This study is to evaluate compaction grouting activity by in-situ and laboratory experiments before, during and after the remedial work. The intensive site investigation and geophysical survey were conducted during and after the compaction grouting work. The compaction grouting work was carried out for the damaged dam core between June 16 and August 24, 2000. The leakage reduction generally occurred in the core of the dam after the remedial work. The use of compaction grouting was considered the proper countermeasures for repairing the damaged dam. It shows that the loose or voided zones have been properly filled and the leakage has been reduced by about 96% of that before the treatment of the remedial work performed at dam core by compaction grouting.