농업용 저수지 둑 높이기에 따른 제체의 침투류 해석

이달원,이광솔,이영학,Lee, Dal-Won,Lee, Kwang-Sol,Lee, Young-Hak 충남대학교 농업과학연구소 2011 Korean Journal of Agricultural Science Vol.38 No.3

This study was carried out to safety evaluation, the practical application and improvement of design method of the agricultural reservoir due to raising embankments. Also, it was to compare and analyze the pore water pressure (PWP), seepage (leakage) quantity and piping phenomenon according to high water table and rapid drawdown. The seepage analysis by finite element analysis was used for steady state and transient condition. The pore water pressure distribution for steady state and transient condition showed positive(+) PWP on the upstream slope, it was gradually changed negative(-) PWP on the downstream slope. The PWP in the core ranged from 100 ~ -33 kPa, the seepage line in the incline-type core suddenly decreased towards the lower levels from the higher levels. The PWP according to rapid drawdown is remained in the vicinity of the upstream slope, therefore, it is investigated to be in an unstable state by the slope stability analysis. The PWP after raising embankments showed smaller than in the before raising embankments. It was likely to be the piping phenomenon because the gradients in the before raising embankments showed largely at downstream slope, and the stability for piping in the after raising embankments increased stable state. The seepage quantity per 1 day and the leakage per 100m for the steady state and transient condition appeared to be safe against the piping. It reduced slightly regardless of the transient condition before the raising embankments and it decreased largely about 2.4 times in the early days after the raising embankments.

지역 스포츠이벤트의 경제적 파급효과 분석에 관한 연구

송석록(Sok Rok Song),이재우(Jae Woo Lee),이달원(Dal Won Lee) 한국사회체육학회 2007 한국사회체육학회지 Vol.0 No.31

The purpose of this study was to analyze the economic impact of sports event as a part of sports marketing strategies of local city. To reach the purpose, Index of S city for 6 years - number of the sports events, public investment, survey for consumption, and Input-Output analysis. - were researched. S city held most sports event with 8 in 2001 and invested 14.8 million won. The most investment was 39.6 million won with 4 Sports events in 2003. The Production inducing effect reached 2,019 million won in 2001, 3,054 million won in 2002, 3,091 million won in 2003, 538 million won in 2004, 542 million won in 2005 and 1,548 million won in 2006. The highest income inducing effect was 862 million won in 2002 with 7 sports events, the employment inducing effect was calculated to 95 persons in 2002 and 94 persons in 2003, and the valued-added inducing effect was 1,738 million won in 2002. The most economic effects were higher than the average effects of whole other industries in Gangwondo which imply that the in S city held sports events contribute to regional development and more regional sports marketing.

1차와 2차 침하를 고려한 압밀침하량 예측

이달원,정성규,Lee, Dal-Won,Jeong, Seong-Gyu 한국농공학회 2005 한국농공학회논문집 Vol.47 No.1

In this study, it was proposed that an equation for predicting consolidation settlement on soft clay ground, which separate total settlement into primary and secondary consolidation settlement equation. The consolidation settlements by the proposed equation and by the measured settlements from laboratory model test were compared and verified for its application. It was appeared that the proposed equation from the laboratory model test approach to be more realistic comparing to !the result of Terzaghi's equation. From the above application, it was concluded that the final settlement prediction by. the Hyperbolic, Asaoka methods is needed to the initial settlement but the proposed equation could be much applicable in the lacking condition of measured data of the initial period.

Estimation of Degree of Consolidation in Soft Ground Using Field Measurements and Rheology Model

이달원,윤현정,Lee, Dal-Won,Yoon, Hyun-Jung The Korean Society of Agricultural Engineers 2005 한국농공학회논문집 Vol.47 No.2

In this research, an attempt is made to derive the practical estimation of the degree of consolidation in soft clay from field measurements under embankments. For the practical estimation of pore water pressure in soft clay, the elasto-viscous rheological model was proposed, with a transform of parameters and a field geotechnical measurements in southern Korea. By using the rheological properties of soft clays and the dissipation of excess pore water pressure behaviour during step loading, a degree of consolidation or pore water pressure estimation in the future can be performed, and are shown to be generally close to the field measurements of pore water pressure. Finally, a pore water pressure behaviour in soft clay can be explained through measured data in field and the excess pore water pressure data can also be used to estimate settlement.

현장계측치로부터 역산한 압축지수와 압밀계수의 평가 방법

이달원,임성훈,김지문,Lee, Dal Won,Lim, Seong Hun,Kim, Ji Moon 충남대학교 농업과학연구소 2000 Korean Journal of Agricultural Science Vol.27 No.1

A large scale field test of prefabricated vertical drains is performed to analyze the effect of parameters of the very soft clay at a test site. Compression index and the coefficient of horizontal consolidation obtained by back-analysis from the settlement data were compared with those obtained by means of laboratory tests. The Hyperbolic, Asaoka's and The Curve fitting methods are used to estimate final settlements and coefficients of consolidation. 1. Final settlement predicted with the Hyperbolic method was the largest, and the settlements predicted with the Asaoka's and the Curve fitting methods were nearly the same range, and it was concluded that smear effect has to be considered on design in the case that spacing of drains is small 2. The relationships of the measured consolidation ratio (Urn) and the designed consolidation ratio($U_t$) were showed as $U_m$ = (1.13~1.17)$U_t$, $U_m$ = (1.07~1.20)$U_t$, $U_m$ = (1.13~1.17)$U_t$ on the Hyperbolic, Asaoka's and the Curve fitting methods, respectively. The relations on the Asaoka's and the Curve fitting methods were nearly the same range. 3. The relationships of the field compression index($C_{cfield}$) and virgin compression index($V_{cclab}$) were showed as $C_{cfield}$ = (1.26~1.45)$V_{cclab}$, $C_{cfield}$ = (1.08~1.15) $V_{cclab}$, $C_{cfield}$ = (1.04~1.21)$V_{cclab}$, on the Hyperbolic, Asaoka's and the Curve fitting methods, respectively. 4. The ratio ($C_h/C_v$) of the coefficient of vertical consolidation and the coefficient of horizontal consolidation that is obtained by back-analysis from the settlement data was $C_h$=(0.7~0.9)$C_v$, $C_h$=(0.9~1.5)$C_v$, $C_h$=(2.4~3.0)$C_v$ on the Hyperbolic, Asaoka's and the Curve fitting methods, respectively. 5. It was concluded that the exact consolidation coefficient must be determined after the final settlement is predicted again when the consolidation is finished, because the field consolidation coefficient is decreased as the time allowed to be alone is increased.

연약지반상에 축조된 농업용저수지의 과잉공극수압 예측과 압밀계수의 비교

이달원,김은호,Lee, Dal-Won,Kim, Eun-Ho 한국농공학회 2010 한국농공학회논문집 Vol.52 No.2

This study was carried out to comparison of coefficient of consolidation and the prediction of excess pore water pressure in agricultural reservoir on soft clay ground. For the purpose of verification of the proposed equation, laboratory model tests and field tests were performed and excess pore water pressure was compared to those predicted with the Terzaghi's method. The predicted excess pore water pressure according to ponding was very applicable to practice because it was close to the observed data. Also, for the comparison of coefficient of consolidation, the oedometer, constant rate of strain (CRS), and Rowe cell tests were performed. The coefficient of consolidation at the Rowe cell and CRS tests showed a greate increase than in the oedometer test. The ratio of the vertical and horizontal coefficient of consolidation showed a large difference according to various tests method and mixing ratio. Therefore, it is recommended that careful attention should be paid to predicting the required consolidation period in agricultural reservoir.

Ni 가 첨가된 (Zr0.8Sn0.2)TiO4 세라믹스의 미세구조와 고주파유전성질

이달원,남산,변재동,김명호 ( Dal Won Lee,Sahn Nahm,Jae Dong Byun,Myong Ho Kim ) 한국전기전자재료학회 1996 한국전기전자재료학회 추계학술대회논문집 Vol.1996 No.0

현장계측에 의한 농업용저수지 제체의 안정관리기법

이달원,오범환,Lee, Dal-Won,Oh, Beom-Hwan 충남대학교 농업과학연구소 2003 Korean Journal of Agricultural Science Vol.30 No.2

This study was performed to suggest a rational method for the stability evaluation of agricultural reservoir in the very soft ground. The stability methods for agricultural reservoir was used to compare and analyze with various condition by limit equilibrium method. The behavior of settlement-displacement obtained by field monitoring system was used to compare and analyze with various stability methods, and to investigate the applicability of the methods for stability evaluation of agricultural reservoir. The horizontal displacement was abruptly increased when physical properties of soft clay reached its maximum values and therefore, the values of these properties could be used to the fundamental data for stability evaluation. The evaluation of the stability of agricultural reservoir was suggested to use the inclination of curve rather than critical line.

페이퍼드레인 공법에 의한 연약지반의 압밀거동

이달원,강예묵,김성완,지인택,Lee, Dal Won,Kang, Yea Mook,Kim, Seong Wan,Chee, In Taeg 충남대학교 농업과학연구소 1997 Korean Journal of Agricultural Science Vol.24 No.2

The large scaled field test by prefabricated vertical drains was performed to evaluate the superiority of vertical discharge capacity for drain materials through compare and analyze the time-settlement behavior with drain spacing and the compression index and consolidation coefficient obtained by laboratory experiments and field monitoring system. 1. The relation of measurement settlement($S_m$) versus design settlement($S_t$) and measurement consolidation ratio($U_m$) versus design consolidation ratio($U_t$) were shown $S_m=(1.0{\sim}1.1)S_t$, $U_m=(1.13{\sim}1.17)U_t$ at 1.0m drain spacing and $S_m=(0.7{\sim}0.8)S_t$, $U_m=(0.92{\sim}0.99)U_t$ at l.5m drain spacing, respectively. 2. The relation of field compressing index($C_{cfield}$) and virgin compression index($V_{cclab.}$) was shown $C_{cfield}=(1.0{\sim}1.2)V_{cclab.}$, But it was nearly same value when considered the error with determination method of virgin compression index and prediction method of total settlement. 3. Field consolidation coefficient was larger than laboratory consolidation coefficient, and the consolidation coefficient ratio($C_h/C_v$) were $C_h=(2.4{\sim}3.0)C_v$. $C_h=(3.5{\sim}4.3)C_v$ at 1.0m and 1.5m drain spacing and increased with increasing of drain spacing. 4. The evaluation of vertical discharge capacity with drain spacing from the results of the consolidation coefficient ratio showed largely superior in case the Mebra drain and Amer drain than other drain materials at 1.0m and 1.5m drain spacing, while the values showed nearly same value in case same drain spacing.

재생골재를 이용한 연약지반개량

이달원,이정준,김시중,Lee, Dal-Won,Lee, Jung-Jun,Kim, Si-Jung 충남대학교 농업과학연구소 2010 Korean Journal of Agricultural Science Vol.37 No.1

In this study, a laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use alternative material of sand in soft ground is performed. The vertical and horizontal coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~4.0 times and 3.0~3.3 times greater than sand, respectively. Therefore, it showed enough to be an alternative material to the sand which had been being used as the vertical and horizontal drainage material before. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. When water level drops suddenly, the pore water pressure of the recycled aggregate and crushed aggregate is reduced to nearly zero. Therefore, it was applicable to the field because discharge capacity was similarity to that of sand. The settlement in crushed aggregates and recycled aggregate decreases gradually with the load increase. When water level drops suddenly, earth pressure in all drains materials was evaluated the equivalent drainage capacity similarity to sand because it show approaching the nearly zero.