• Title, Summary, Keyword: rock

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Methodology to Quantify Rock Behavior in Shallow Rock Tunnels by Analytic Hierarchy Process and Rock Engineering Systems (계층 분석적 의사결정과 암반 공학 시스템에 의한 저심도 암반터널에서의 암반거동 유형 정량화 방법론)

  • Yoo, Young-Il;Kim, Man-Kwang;Song, Jae-Joon
    • Tunnel and Underground Space
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    • v.18 no.6
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    • pp.465-479
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    • 2008
  • For the quantitative identification of rock behavior in shallow tunnels, we recommend using the rock behavior index (RBI) by the analytic hierarchy process (AHP) and the Rock Engineering Systems (RES). AHP and RES can aid engineers in effectively determining complex and un-structured rock behavior utilizing a structured pair-wise comparison matrix and an interaction matrix, respectively. Rock behavior types are categorized as rock fall, cave-in, and plastic deformation. Seven parameters influencing rock behavior for shallow depth rock tunnel are determined: uniaxial compressive strength, rock quality designation (RQD), joint surface condition, stress, pound water, earthquake, and tunnel span. They are classified into rock mass intrinsic, rock mass extrinsic, and design parameters. An advantage of this procedure is its ability to obtain each parameter's weight. We applied the proposed method to the basic design of Seoul Metro Line O and quantified the rock behavior into RBI on rock fall, cave-in, and plastic deformation. The study results demonstrate that AHP and RES can give engineers quantitative information on rock behavior.

Modeling or rock slope stability and rockburst by the rock failure process analysis (RFPA) method

  • Tang, Chun'an;Tang, Shibin
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • pp.89-97
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    • 2011
  • Brittle failure of rock is a classical rock mechanics problem. Rock failure not only involves initiation and propagation of single crack, but also is a complex problem associated with initiation, propagation and coalescence of many cracks. As the most important feature of rock material properties is the heterogeneity, the Weibull statistical distribution is employed in the rock failure process analysis (RFPA) method to describe the heterogeneity in rock properties. In this paper, the applications of the RFPA method in geotechnical engineering and rockburst modeling are introduced with emphasis, which can provide some references for relevant researches.

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Anchorage mechanism and pullout resistance of rock bolt in water-bearing rocks

  • Kim, Ho-Jong;Kim, Kang-Hyun;Kim, Hong-Moon;Shin, Jong-Ho
    • Geomechanics and Engineering
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    • v.15 no.3
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    • pp.841-849
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    • 2018
  • The purpose of a rock bolt is to improve the mechanical performance of a jointed-rock mass. The performance of a rock bolt is generally evaluated by conducting a field pullout test, as the analytical or numerical evaluation of the rock bolt behavior still remains difficult. In this study, wide range of field test was performed to investigate the pullout resistance of rock bolts considering influencing factors such as the rock type, water bearing conditions, rock bolt type and length. The test results showed that the fully grouted rock bolt (FGR) in water-bearing rocks can be inadequate to provide the required pullout resistance, meanwhile the inflated steel tube rock bolt (ISR) satisfied required pullout resistance, even immediately after installation in water-bearing conditions. The ISR was particularly effective when the water inflow into a drill hole is greater than 1.0 l/min. The effect of the rock bolt failure on the tunnel stability was investigated through numerical analysis. The results show that the contribution of the rock bolt to the overall stability of the tunnel was not significant. However, it is found that the rock bolt can effectively reinforce the jointed-rock mass and reduce the possibility of local collapses of rocks, thus the importance of the rock bolt should not be overlooked, regardless of the overall stability.

Study on Rock classification of Rock Socketed Drilled Shaft (현장타설말뚝의 암반 근입부 암판정 사례연구)

  • Park, Woan-Suh;Yoo, Jai-Hyun;Lee, Woo-Cheol;Joo, Yong-Sun
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.658-663
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    • 2010
  • Recently the most of deep foundation were socketed into weathered rock or soft rock to carry large foundation loads. The end bearing behavior of piles socketed in rock is generally dependent on the rock mass conditions with discontinuities and rock strength. Therefore, it is very important that the estimating rock classification with relation of TCR, RQD and unpredicted rock condition. In this study, the construction failure example of drilled shaft due to mistaking to estimate the rock classification on penetration were analyzed in site, so we hope to discuss problems of determining the rock socketed length of drilled shaft on construction.

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The Characteristice of Safety on a Slope of Pyroclastic Rock (화산쇄설암 사면의 안정 특성)

  • Kim, Byoung-Gon;Park, Sung-Kwon;Choi, Kil-Hyun;Baek, Seung-Cheol
    • 한국방재학회:학술대회논문집
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    • pp.557-560
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    • 2008
  • In this paper, it discusses about the stability of rock slope of pyroclastic rock, which can easily meet at construction site. Basically carry out the investigation about the development of a surface of discontinuity, too. With that, it refers to the basic groups of sedimentary rock, treats of general details about investigation of rock slope and stability analysis, and discusses general characteristics and stability analysis case study about rock slope of pyroclastic rock. Achieved basic geological investigation on rock slope of pyroclasic rock, and examine the stability of slope by doing limit equilibrium and geometric stability analysis due to the result of investigation. It is considered to be able to accumulate many data about slope design of pyroclastic rock hereafter estimating degrees of rock mass properties of pyroclastic rock quantitatively.

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Rock Music Inspiration Represented in Hedi Slimane's Menswear Design (에디 슬리먼의 남성복 디자인에 나타난 록(Rock) 뮤직 영감)

  • Lee, Hae-Dong;Suh, Sung-Eun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.40 no.2
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    • pp.353-364
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    • 2016
  • This study analyzes French designer Hedi Slimane who has received recent attention from the fashion world. He changed sub-culture 'Rock Fashion' into high fashion and altered the stereotype of the existing menswear with the skinny look. His extreme slim-fit style also has changed the menswear market dramatically. Hedi Slimane was mainly inspired by various rock music genres from the 1960 to 2000s such as glam rock, psychedelic rock, grunge rock, and garage rock. He showed in his own rock style when creating his collection. The collections inspired from the specific rock music and style were selected from Dior Homme (2001F/W-2007F/W) and Saint-Laurent (2013F/W-2015F/W), and analyzed by the 4 genres of rock music and fashion style as follows. First, glam rock style appeared in Dior Homme 2005F/W and Saint Laurent 2014S/S with glamorous full make-up, animal printings, and glitter textures. Second, psychedelic rock style appeared in Saint Laurent 2015S/S with flower patterns, afro hair, fur vests, and western & ethnic bohemian styling. Third, grunge rock style appeared at Dior Homme 2005S/S and Saint Laurent 2013F/W with messedup hair, destroyed jeans, and layering style. Fourth, garage rock style appeared mainly at Dior Homme 2006 S/S with messed-up hair, slim suit, fedora, and sneakers. This result is expected to be used for research and development on modern rock style for contemporary menswear.

Effects of rock-support and inclined-layer conditions on load carrying behavior of piled rafts

  • Roh, Yanghoon;Kim, Garam;Kim, Incheol;Lee, Junhwan
    • Geomechanics and Engineering
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    • v.18 no.4
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    • pp.363-371
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    • 2019
  • In this study, the load carrying behavior of piled rafts installed in inclined bearing rock layer was investigated for rock-mounted and -socketed conditions. It was found that settlements induced for an inclined bearing rock layer are larger than for a horizontal layer condition. The load capacity of piled rafts for the rock-mounted condition decreased as rock-layer inclination angle (${\theta}$) increased, while vice versa for the rock-socketed condition. The load capacities of raft and piles both decreased with increasing ${\theta}$ for the rock-mounted condition. When bearing rock layer was inclined, loads carried by uphill-side piles were greater than those by downhill-side piles. The values of differential settlements of rock-mounted and -socketed conditions were not significantly different whereas slightly higher for the rock-socketed condition. The values of load sharing ratio (${\alpha}_p$) and its variation with settlement were not markedly changed by the inclination of bedrock. It was shown that ${\alpha}_p$ for piled rafts installed in rock layer was not affected by ${\theta}$ whereas actual loads carried by raft and piles may vary depending on the pile installation and rock-layer inclination conditions.

Bearing capacity of shallow foundations on the bilayer rock

  • Alencar, Ana S.;Galindo, Ruben A.;Melentijevic, Svetlana
    • Geomechanics and Engineering
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    • v.21 no.1
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    • pp.11-21
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    • 2020
  • The traditional formulations for estimation of bearing capacity in rock mechanics assume a homogeneous and isotropic rock mass. However, it is common that the rock mass consists of different layers of different rock properties or of the same rock matrix with distinct geotechnical quality levels. The bearing capacity of a heterogeneous rock is estimated traditionally through the weighted average. In this paper, the solution of the weighted average is compared to the finite difference method applied to a bilayer rock mass. The influence of different parameters such as the thickness of the layers, the rock type, the uniaxial compressive strength and the overall geotechnical quality of the rock mass on the bearing capacity of a bilayer rock mass is analyzed. A parametric study by finite difference method is carried out to develop a bearing capacity factor in function of the layer thickness and the rock mass quality expressed in terms of the geological strength index, which is presented in a form of a chart. Therefore, this correlation factor allows estimating the bearing capacity of a rock mass that is formed by two layers with distinct GSI, depending on the bearing capacity of the rock mass formed only by the upper layer and considered by that way as homogenous and isotropic rock mass.

A review of experimental and numerical investigations about crack propagation

  • Sarfarazi, Vahab;Haeri, Hadi
    • Computers and Concrete
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    • v.18 no.2
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    • pp.235-266
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    • 2016
  • A rock mass containing non-persistent joints can only fail if the joints propagate and coalesce through an intact rock bridge. Shear strength of rock mass containing non-persistent joints is highly affected by the both, mechanical behavior and geometrical configuration of non-persistent joints located in a rock mass. Existence of rock joints and rock bridges are the most important factors complicating mechanical responses of a rock mass to stress loading. The joint-bridge interaction and bridge failure dominates mechanical behavior of jointed rock masses and the stability of rock excavations. The purpose of this review paper is to present techniques, progresses and the likely future development directions in experimental and numerical modelling of a non-persistent joint failure behaviour. Such investigation is essential to study the fundamental failures occurring in a rock bridge, for assessing anticipated and actual performances of the structures built on or in rock masses. This paper is divided into two sections. In the first part, experimental investigations have been represented followed by a summarized numerical modelling. Experimental results showed failure mechanism of a rock bridge under different loading conditions. Also effects of the number of non-persistent joints, angle between joint and a rock bridge, lengths of the rock bridge and the joint were investigated on the rock bridge failure behaviour. Numerical simulation results are used to validate experimental outputs.

Prediction models of the shear modulus of normal or frozen soil-rock mixtures

  • Zhou, Zhong;Yang, Hao;Xing, Kai;Gao, Wenyuan
    • Geomechanics and Engineering
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    • v.15 no.2
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    • pp.783-791
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    • 2018
  • In consideration of the mesoscopic structure of soil-rock mixtures in which the rock aggregates are wrapped by soil at normal temperatures, a two-layer embedded model of single-inclusion composite material was built to calculate the shear modulus of soil-rock mixtures. At a freezing temperature, an interface ice interlayer was placed between the soil and rock interface in the mesoscopic structure of the soil-rock mixtures. Considering that, a three-layer embedded model of double-inclusion composite materials and a multi-step multiphase micromechanics model were then built to calculate the shear modulus of the frozen soil-rock mixtures. Given the effect of pore structure of soil-rock mixtures at normal temperatures, its shear modulus was also calculated by using of the three-layer embedded model. Experimental comparison showed that compared with the two-layer embedded model, the effect predicted by the three-layer embedded model of the soil-rock mixtures was better. The shear modulus of the soil-rock mixtures gradually increased with the increase in rock regardless of temperature, and the increment rate of the shear modulus increased rapidly particularly when the rock content ranged from 50% to 70%. The shear modulus of the frozen soil-rock mixtures was nearly 3.7 times higher than that of the soil-rock mixtures at a normal temperature.