• 한국농공학회논문집
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• 제56권6호
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• pp.63-73
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• 2014

In this study, the large scale test was performed to investigate the behavior of failure on the embankment and spillway transitional zone by overtopping. The pore water pressure, earth pressure, settlement and failure behaviors according to several reinforcing method were compared and analyzed. The pore water pressure showed a small change in the spillway transition zone and core, indicating that the riprap and geotextile efficiently reinforced the embankment, but non-reinforcement showed a largely change in pore water pressure. The earth pressure by riprap and geotextile at upstream slope and bottom core increased rapidly with the infiltration of the pore water by overtopping. And the earth pressure at crest showed a smally change due to effect of the inclined core. A settlement by riprap showed a small change and the geotextile decreased a rapidly due to failure of crest. The width of failure by riprap at intermediate stage (50 min) showed a largely due to sliding of crest. But, the width and depth of the seepage erosion after the intermediate overtopping period (100 min) were very small due to the effect of riprap than geotextile and non-reinforcement which delayed failure. It has the effect that protect reservoir embankment from erosion in the central part. The pore water pressure at the spillway transition zone due to overtopping increased a rapidly in the case of non-reinforcement, but the reinforced methods by geotextile and riprap showed a smally change. Therefore, the reinforced method by riprap and geotextile was a very effective method to protect permanently and the emergency an embankment due to overtopping, respectively.

• 한국지반공학회논문집
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• 제25권2호
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• pp.25-35
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• 2009

사면붕괴는 매년 인간의 활동에 엄청난 재정적 손실을 끼치는 중요한 재난중의 하나이다. 사면의 붕괴특성을 고찰한 결과 강우와 매우 밀접한 상관성이 있음을 알 수 있었다. 기존 연구에 따르면 우기시 강우로 인한 간극수압의 영향으로 인하여 대부분의 사면붕괴 사고가 발생하였다. 기존사면의 안전율은 사면의 풍화 등 열화 거동과 강우 등의 작용으로 인해 점차 감소하고 있으나 식생, 보호공, 보강공 등으로 인해 안전율을 상승시키는 활동이 가미되어 실제기존사면의 적정한 평가가 어렵다. 따라서 사면의 절취 및 보수보강이 완료된 직후부터 현재까지의 안정성에 영향을 미치는 요소를 누적적으로 고려할 수 있는 시간 의존적 해석도구가 필요하다. 본 연구에서는 변위-간극수압을 고려한 연계 수치해석 기법을 채택하여 무보강 사면과 보강사면으로 구분하여 시간 의존적 거동을 고려하는 수치해석(coupled numerical analysis)을 실시하였다. 이로부터 기존사면의 간극수압에 따른 영향을 평가하고, 연계해석을 해석 도구로 하는 안정해석 기술을 제시하고자 하였다.

• 지질공학
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• 제17권1호
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• pp.57-64
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• 2007

본 연구는 국내에서 산자태 발생빈도가 매우 높은 편마암 풍화토를 대상으로 산사태 모형실험장치를 이용하여 강우강도 및 사면경사에 따른 간극수압 변화의 관계를 파악하기 위하여 수행되었다. 본 연구에서는 강우강도와 사면경사의 변화에 따른 다양한 실험조건하에서 일정 시간 간격으로 간극수압, 사면붕괴양상 및 변위 등을 각각 측정하였다. 실험결과에 따르면, 강우강도에 따른 간극수압의 관계는 강우강도가 클수록 간극수압 증가시간이 빠르며, 모형 토조의 위치별 간극수압 증가시간도 사면 상부에서 가장 빠른 것으로 측정되었다. 이를 표준사를 이용한 실험결과(채병곤 외, 2006)와 비교해 볼 때, 편마암 풍화토는 강우의 침투속도가 표준사에 비해 느린 것을 알 수 있으며, 이로 인해 사면하부로의 강우이동이 상대적으로 원활하지 않아 사면 상단부에서 간극수압의 증가가 빠른 것으로 해석된다. 한편, 간극수압의 증가는 사면의 경사가 작은 경우 먼저 발생하는 것으로 나타났다. 이러한 현상 역시 편마암 풍화토의 느린 강우 침투속도에 기인하는 것으로 생각된다.

• 한국농공학회논문집
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• 제52권2호
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• pp.1-9
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• 2010

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.

• 한국농공학회지
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• 제30권3호
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• pp.38-50
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• 1988

carried out to present a rheology model which is able to treat time-dependent properties of clay. The results were summarized as follow ; 1. The slope (a(e1)) of deviator stress in strain rate test was independent on axial strain, and pore water pressure was decreased with increment of strain rate. 2. The pore water pressure in a stress relaxation condition was not changed when the strain rate before stress relaxation was 0.05%/min., but it was increased with increment of time when the strain rate before stress relaxation was 0.2%/min 3. The greater the stress condition (q/qmax) and the strain rate before creep test became, the greater the increment rate of axial strain in creep test became. 4. SEKIGUCHI's constitutive equation was slightly overpredicted while empirical equation proposed in the study was well coincided with measured values. 5. The constitutive equation induced by a strain function could be dealed with a behavior of the pore water pressure increased with increment of elapsed time after primary consolidation.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.382-387
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• 1998

Triaxial compression tests were run to study on the undrained strength characteristics of fiber mixed kaolin clay(Hadong). The influence of various test parameters such as amount and aspect ratio(ratio of length to diameter) of fiber, confining stress was also investigated. Test results showed that the increase in aspect ratio was increased in deviator stress at failure, but no effect on pore water pressure at failure. Deviator stress at failure was also increased at 0.5％ mixing ratio(weight fraction of fiber to that of soil solid) of fiber but it was, thereafter, decreased and wits reached to constant after 2％ mixing ratio. On the contrary, Pore water pressure at failure was increased as mixing ratio of fiber was greater than 1%. Deviator stress and pore water pressure of both clay and fiber mixed clay(FMC) at failure were increased as confining stress was increased. Deviator stress of FMC at failure was about 10％ larger than that of clay, but pore water pressure of FMC at failure was almost similar to that of clay.

• 한국농공학회논문집
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• 제50권2호
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• pp.37-44
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• 2008

A theoretical equation was proposed to consider the effect of ponding for the excess pore water pressure in agricultural reservoir on soft clay ground. The value of excess pore water pressure predicted using the proposed equation was compared to those predicted with the Terzaghi's method and the finite difference method(FDM), respectively, for the purpose of verification. The degree of consolidation according to ponding predicted by applying the proposed equation was close to the observed degree of consolidation on the double drainage condition(at DP-3) but it was less than the observed degree of consolidation on the single drainage condition(at DP-5). The equation was very applicable to practice because the analysis result by the equation was close to the observed data.

• 지구물리
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• 제6권2호
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• pp.57-69
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• 2003

In this paper the theoretical method to analyse the pore water pressures in the bed under the oscillating water pressure is developed. In the former researches the validity of the theoretical treatment for the one-dimensional problem has been verified. However, the one-dimensional treatment is not sufficient to obtain the precise information concerning the many practical problems. From this point of view, in this study, we derive the fundamental equations for the general three-dimensional sand layer under the oscillating water pressure. The validity of this theoretical method is verified by experiments for the two-dimensional problems.

• 한국지반공학회논문집
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• 제23권6호
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• pp.77-84
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• 2007

유입량과 라이닝에 작용하는 간극수압은 터널 설계시 고려해야 할 중요한 요소 중 하나이다. 간극수압의 발생은 누수를 가속화시키며 라이닝 열화를 초래한다. 본 논문에서는 모형실험을 통하여 배수시스템 기능저하로 인한 간극수압의 발생과 그 영향을 조사하였다. 배수시스템 기능저하거동은 배수재의 투수계수제어법과 유량 조절법으로 모사화 하여 터널 라이닝의 잔류수압발생 메카니즘을 확인하였다. 또한, 유량제어법이 배수시스템 기능저하현상을 모사하기에 보다 더 효과적인 방법임을 알 수 있었다. 모형실험을 수치해석으로 재현한 결과, 배수시스템 기능저하로 인한 영향을 Coupled 수치 모델링을 통해 이론적으로 예측 가능함을 확인할 수 있었다.

• 한국세라믹학회지
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• 제50권1호
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• pp.25-30
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• 2013

The pore volume of hardened cement with waterproofing materials is lower compared to that of hardened cement without waterproofing materials. Thus, fewer gaps will appear by means of chemical reactions between $Ca^{2+}$ ions in hardened cement and water, solutes, and other ions. Due to the selective permeability, the osmotic pressure of hardened cement can change due to physical effects such as the reduction of the pore volume and the reduction in the number of pores, as well as by the electrochemical reaction between water, solutes, other ions and $Ca^{2+}$ ions in hardened cement. Of course, these factors do not have independent effects but instead a combined complex effect. Accordingly, we studied changes in the osmotic pressure due to the difference in the pore structure of hardened cement. A pore size smaller than 1 nm in hardened cement had only a slight effect on the osmotic pressure, whereas a pore size larger than 1 nm had a direct effect on the osmotic pressure.