• Title/Summary/Keyword: Lugeon value

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The Impermeable Effect for Bedrock Constructed by Grouting (기반암에서 그라우팅에 의한 차수효과)

  • Yea, Geuguwen
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.2
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    • pp.51-59
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    • 2009
  • This study is based on field data obtained from rock grouting such as RQD value, Unit cement grout volume, Lugeon value(Lu), and Maximum grout pressure in four different dam sites. The relationship were analyzed and compared as follow. The cut-off effect after rock grouting in dam-foundation which are mostly consist of metamorphic rock is better than that of Sedimentary rock. And the impermeable effect after consolidation grouting is more efficiency than the impermeable effect after curtain grouting. The unit cement grout volume are increased as RQD value is higher in rock mass. But there is no relationship between RQD value and Lugeon value. In the sedimentary rock, which is more permeable than metamorphic rock, Lugeon value (Lu) is a linear function (Lu=0.22Vc) of unit cement grout volume (Vc). Cut-off effect of curtain grouting is less influential at each near holes which are already grouted than that of consolidation grouting. And the behavior characteristics of Lugeon value vs. the unit cement grout volume as the order of installations are almost the same.

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A Study on the Impermeable Effect by Grouting in the Subsea Tunnel (해저터널에서 주입에 의한 차수효과 연구)

  • Kim, Seunghwan;Lim, Heuidae;Yoon, Seongmin
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.6
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    • pp.5-19
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    • 2017
  • In this study, the effect of rock mass curtain grouting was investigated by analyzing the correlation between the parameters of the RMR & grout injection volume, Lugeon value & RQD, Lugeon value & cement injection volume. In order to investigate the effect of rock mass curtain grouting, we analyzed the grout injection volume of 315 curtain grouting holes at 9 tunnel face of NATM Subsea tunnels in gneiss area. The total grout injection volume in the Subsea tunnels study was slightly changed in some tunnels face but decreased with increasing the rating of parameters in spacing of discontinuity (R3, Js) and groundwater condition (R5). The geological anomalies of seismic survey (3D, TSP) and the inflow of probe hole were found to be more correlated of relative than the parameters of RMR. The unit injection volume was found to decrease with higher ratings in the parameters of the RMR except the weathering degree of the discontinuity (Jc, R4). The correlation between RQD and Lugeon values is not significant, but it can be confirmed that the Lugeon value tends to decrease as the RQD value increases.

Trends in Predicting Groutability Based on Correlation Analysis between Hydrogeological and Rock Engineering Indices: A Review (수리지질 및 암반공학 지수 간 상관분석을 통한 절리암반 내 그라우트 주입성 예측 연구 동향: 리뷰논문)

  • Kwangmin Beck;Seonggan Jang;Seongwoo Jeong;Seungwoo Jason Chang;Minjune Yang
    • The Journal of Engineering Geology
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    • v.33 no.2
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    • pp.307-322
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    • 2023
  • Rock-mass grouting plays a crucial role in the construction of dams and deep caverns, effectively preventing seepage in the foundations, enhancing stability, and mitigating hazards. Most rock grouting is affected by hydrogeological and rock engineering indices such as rock quality designation (RQD), rock mass quality (Q-value), geological strength index (GSI), joint spacing (Js), joint aperture (Ap), lugeon value (Lu), secondary permeability index (SPI), and coefficient of permeability (K). Therefore, accurate geological analysis of basic rock properties and guidelines for grouting construction are essential for ensuring safe and effective grouting design and construction. Such analysis has been applied in dam construction sites, with a particular focus on the geological characteristics of bedrock and the development of prediction methods for grout take. In South Korea, many studies have focused on grout injection materials and construction management techniques. However, there is a notable lack of research on the analysis of hydrogeological and rock engineering information for rock masses, which are essential for the development of appropriate rock grouting plans. This paper reviews the current state of research into the correlation between the grout take with important hydrogeological and rock engineering indices. Based on these findings, future directions for the development of rock grouting research in South Korea are discussed.

Correlation between the Distribution of Discontinuities and Groundwater Flow in Fractured Rock (온도검층과 수압시험을 통한 파쇄암반의 단열분포와 지하수 흐름 상관성 고찰)

  • Park, Seunghyuk;Chung, Il-Moon
    • The Journal of Engineering Geology
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    • v.26 no.4
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    • pp.505-513
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    • 2016
  • The qualitative distribution of a fractured aquifer was characterized by electrical resistivity surveying as a part of basic groundwater investigation in Jangseong. The results were then used to choose sites for observation wells. The locations and distributions of permeable discontinuities were studied by analyses of temperature logs, a borehole image-processing system (BIPS), and hydraulic pressure testing using a double packer. The pressure test showed that the size of the discontinuities correlated with the Lugeon value and the results of the temperature log. The results show that temperature measurement is an effective method to identify permeable discontinuities, with the temperature difference correlating with the size of the aperture of the discontinuity.