• Title, Summary, Keyword: RMR

Search Result 368, Processing Time 0.031 seconds

A Study of RMR in Tunnel with Risk Factor of Collapse (터널 붕괴 위험도에 따른 RMR 연구)

  • Jang, Hyong-Doo;Yang, Hyung-Sik
    • Tunnel and Underground Space
    • /
    • v.21 no.5
    • /
    • pp.333-340
    • /
    • 2011
  • RMR is most strongly adopted rock classification method to scheme support system in domestic tunnel. However the RMR, which is based on geological survey during design stage of tunnel, can't present the real ground accurately. In this study, authors suggested Weighted-RMR (W-RMR) which is considered weighted value of risk factors of collapse due to prevent collapse and roof falls during tunneling. According to the application of W-RMR to Bye-Gye tunnel, we could change support type flexibly by the risk factors on a face of tunnel.

A Study of the Relationships among RMR, Q-system and GSI Applied to Classify Rock Mass of Limestone Mine (석회석 광산의 암반 분류에 적용된 RMR, Q-system, GSI 간의 상관성 연구)

  • Yoon, Yong-Kyun;Lee, Hong-Woo
    • Explosives and Blasting
    • /
    • v.35 no.4
    • /
    • pp.27-35
    • /
    • 2017
  • A total of 22 sites around openings of limestone mine are chosen to assess rock mass classification schemes such as RMR, Q-system, and GSI. RMR and Q are modified to estimate the relationship with GSI. Q' is the modified Q with SRF=1.0 and $J_w=1.0$. Rock mass is assumed to be completely dry and very favorable discontinuity orientations are assumed to estimate ${RMR_{89}}^{\prime}$. Relationships of Q-Basic RMR, Q-Total RMR, ${GSI-RMR_{89}}^{\prime}$, and GSI-Q' are analyzed, in which a correlation of ${GSI-RMR_{89}}^{\prime}$ is found to be the highest. Failure strains are calculated using the modulus ratios and most measuring sites appear to be stable with low failure strain class.

Geostatistical Integration of MT and Borehole Data for RMR Evaluation (암반등급 평가를 위한 MT와 시추공 자료의 지구통계학적 복합해석)

  • Oh, Seok-Hoon;Chung, Ho-Joon;Lee, Duk-Kee
    • Geophysics and Geophysical Exploration
    • /
    • v.7 no.2
    • /
    • pp.121-129
    • /
    • 2004
  • The geostatistical approach was applied to integrate MT (Magneto-telluric) resistivity data and borehole information for the spatial RMR (Rock Mass Rating) evaluation. Generally, resistivity of the subsurface is believed to be positively related to the RMR, thus the resistivity and borehole RMR information was combined in a geostatistical approach. To relate the two different sets of data, we take the MT resistivity data as secondary information and estimate the RMR mean values at unsampled points by identification of the resistivity to the borehole data. Two types of approach are performed for the estimation of RMR mean values. Then the residuals of the RMR values around the borehole sites are geostatistically modeled to infer the spatial structure of difference between real RMR values and estimated mean values. Finally, this geostatistical estimation is added to the previous means. The result applied to a real situation shows prominent improvements to reflect the subsurface structure and spatial resolution of RMR information.

A Study on the Uncertainty of the Classification of Rook Mass Rating (RMR 암반분류법의 불확정성에 관한 연구)

  • Lee Sang-Eun;Jun Sung-Kwon;Kang Sang-Jin
    • Tunnel and Underground Space
    • /
    • v.15 no.6
    • /
    • pp.441-451
    • /
    • 2005
  • It is the unavoidable problem that the RMR rock classification method has the uncertainty resulted from uncertain definition of measured value in RMR grade table, hence in this paper, the estimation of probability density function$(p{\cdot}d{\cdot}f)$ graph with the evaluation of continuos RMR and the Monte Carlo Simulation and statistic reasoning were carried out to evaluate the uncertainty quantitatively. Also, the modified RMR rock classification table was presented in order to apply the uncertainty of RMR to the practice, and then the design process of standard support pattern and the tunnel support material was proposed.

A Study on Rock Mass Rating system(RMR) and Modified Method (RMR 분류방법 및 수정 방법의 고찰)

  • 허종석
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • /
    • pp.51-64
    • /
    • 2003
  • Bieniawski에 의해 개발된 RMR은 암석강도 및 불연속면, 지하수 등의 6개 인자에 따라 분류되어, 이들을 합산하여 결정된다. RMR 분류법은 각 요소들에 대한 평가가 비교적 쉽고, 다양한 응용을 거쳐 여러 분야에 적용되어 국내에서도 가장 널리 사용하고 있는 암반분류 방법 중의 하나이다. RMR 분류결과는 터널의 유지시간, 최대 무지보폭의 예측, 지보량 산정, 암반의 물리적 특성값 예측 등에 적용될 수 있다. 또한 RMR 분류법을 사면안정, 댐 기초, 심부 광산 등에 적용하거나, RMR 분류법의 미비한 부분을 보완하기 위한 여러 가지 수정방법이 제시되었다.

  • PDF

The Measurements of the Resting Metabolic Rate (RMR) and the Accuracy of RMR Predictive Equations for Korean Farmers (농업인의 휴식대사량 측정 및 휴식대사량 예측공식의 정확도 평가)

  • Son, Hee-Ryoung;Yeon, Seo-Eun;Choi, Jung-Sook;Kim, Eun-Kyung
    • Korean Journal of Community Nutrition
    • /
    • v.19 no.6
    • /
    • pp.568-580
    • /
    • 2014
  • Objectives: The purpose of this study was to measure the resting metabolic rate (RMR) and to assess the accuracy of RMR predictive equations for Korean farmers. Methods: Subjects were 161 healthy Korean farmers (50 males, 111 females) in Gangwon-area. The RMR was measured by indirect calorimetry for 20 minutes following a 12-hour overnight fasting. Selected predictive equations were Harris-Benedict, Mifflin, Liu, KDRI, Cunningham (1980, 1991), Owen-W, F, FAO/WHO/UNU-W, WH, Schofield-W, WH, Henry-W, WH. The accuracy of the equations was evaluated on the basis of bias, RMSPE, accurate prediction and Bland-Altman plot. Further, new RMR predictive equations for the subjects were developed by multiple regression analysis using the variables highly related to RMR. Results: The mean of the measured RMR was 1703 kcal/day in males and 1343 kcal/day in females. The Cunningham (1980) equation was the closest to measured RMR than others in males and in females (males Bias -0.47%, RMSPE 110 kcal/day, accurate prediction 80%, females Bias 1.4%, RMSPE 63 kcal/day, accurate prediction 81%). Body weight, BMI, circumferences of waist and hip, fat mass and FFM were significantly correlated with measured RMR. Thus, derived prediction equation as follow : males RMR = 447.5 + 17.4 Wt, females RMR = 684.5 - 3.5 Ht + 11.8 Wt + 12.4 FFM. Conclusions: This study showed that Cunningham (1980) equation was the most accurate to predict RMR of the subjects. Thus, Cunningham (1980) equation could be used to predict RMR of Korean farmers studied in this study. Future studies including larger subjects should be carried out to develop RMR predictive equations for Korean farmers.

Application for Prediction of Crown Settlements Using RMR in Weathering Rock Tunnels (RMR을 이용한 풍화암 터널의 천단침하량 예측 평가)

  • Kim, Young-Su;Kim, Dae-Man
    • Journal of the Korean Geotechnical Society
    • /
    • v.25 no.10
    • /
    • pp.67-76
    • /
    • 2009
  • Statistical analysis was performed using a series of data on RMR, RMR* and crown settlements collected from sites of weathering rock tunnels in Korea. The crown settlements were predicted by recurrence analysis, exponential function, and artificial neural network (ANN) using collected in-situ data. The result of the prediction fitted well compared to the measured settlement in the order of ANN, exponential function, and recurrence analysis. The range of crown settlement predicted by recurrence analysis widely scattered and promised larger settlement than the measured. Also in all method, the predicted value by RMR well matched compared to the measured settlement predicted by RMR*.

The Correlation Between RMR and Deformation Modulus by Rock masses using Pressuremeter (공내재하시험을 이용한 암종별 변형계수와 RMR의 상관성)

  • Ahn, Taebong
    • Journal of the Korean GEO-environmental Society
    • /
    • v.12 no.1
    • /
    • pp.5-12
    • /
    • 2011
  • In this study, correlation between measured deformation modulus using pressuremeter and RMR value conducted in 10 sites is analyzed, and applicability of the conventional empirical formulas to the rock masses in Korea are analyzed, It is found that if RMR is below 40, the correlation between deformation modulus and RMR accords Kim Gyo-won's formula and Aydan, Serafim and Pereira's one well, but if the RMR exceeds 40, the correlation was lower than those from the formula. Such results may be attribute to the fact that during classification of RMR, scores are weighed relatively more in joint conditions and apertures than such highly correlational items as uniaxial compression strength or RQD, and RMR would not be evaluated qualitatively due to different weathering degrees and rock mass types as well as engineers' personal errors. Sandstone among sedimentary rocks are quite well accord with suggested equation, but correlation of other rocks are due to large variance. In this study, correlation expressions of various rocks are proposed as the function of exponential based on the field test data.

Comparison of the RMR Ratings by Tunnel Face Mappings and Horizontal Pre-borings at the Fault Zone in a Tunnel (터널 단층대에서 수평시추와 막장관찰에 의한 RMR값의 비교 분석)

  • Kim Chee-Hwan
    • Tunnel and Underground Space
    • /
    • v.15 no.1
    • /
    • pp.39-46
    • /
    • 2005
  • The RMR ratings, one by horizontal pre-boring in a tunnel and another by tunnel face mapping, are compared at the fault zone in a tunnel. Generally. the horizontal pre-borings were so effective as to forecast reasonably the supporting patterns after tunnel excavation. But the maximum difference in RMR ratings estimated by two methods was about 50 at a certain section of a tunnel. The differences were analyzed on each parameter of the RMR system: the rating differences were 24 in the condition of discontinuities, 15 in the RQD and 13 in the uniaxial compressive strength of rock. To minimize the gap between RMR by pre-borings and by face mappings, it is necessary to select the horizontal pre-boring location where tunnel stability could be critical and to evaluate in detail the sub-parameters of the condition of discontinuities.

Effect of RMR and rock type on tunnel drilling speed (RMR과 암석종류가 터널 천공속도에 미치는 영향)

  • Kim, Hae-Mahn;Lee, In-Mo;Hong, Chang-Ho
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.21 no.4
    • /
    • pp.561-571
    • /
    • 2019
  • Drilling and charging of the blast holes during NATM tunneling works take more than 30% of construction time among the whole tunneling work process. Prediction of ground condition ahead of tunnel face has been studied by several researchers by correlating percussion pressure and drilling speed during tunneling work with the ground condition and/or RMR values. However, most of the previous researches were conducted in the granite rock condition which is the most representative igneous rock in the Korean peninsula. In this study, drilling speeds in igneous rocks were analyzed and compared with those in sedimentary rocks (most dominantly composed of conglomerates, sandstones, and shales) under the similar RMR ranges; it was identified that the drilling speed is pretty much affected by rock types even in a similar RMR range. Under the similar RMR values, the drilling speed was faster in sedimentary rocks compared with that in igneous rock. Moreover, while the drilling speed was not much affected by change of the RMR values in igneous rocks, it became faster in sedimentary rocks as the RMR values got lower.