• Title/Summary/Keyword: Rock-fall

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Finite element impact analysis for the design of structurally dissipating rock-shed

  • Zhang, Yi;Toutlemonde, Francois;Lussou, Philippe
    • Computers and Concrete
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    • v.6 no.2
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    • pp.109-132
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    • 2009
  • This paper presents finite element impact analysis for the design of Structurally Dissipating Rock-shed (SDR), an innovative design of reinforced concrete rock-shed. By using an appropriate finite element impact algorithm, the SDR structure is modelled in a simplified but efficient way. The numerical results are firstly verified through comparisons with the results of the experiments recently realized by ESIGEC and TONELLO I.C. It is shown that, using this impact algorithm, it is possible to correctly predict the SDR structural behaviour under different rock-fall impact conditions. Moreover, the numerical results show that the slab centre is the critical impact location for reinforced concrete slab design. The impact analyses have thus been focused on the impacts at the slab centre for the SDR structural optimization. Several series of parametric studies have been carried out with respect to load cases and engineering parameters choices. These numerical results support the robustness of the new SDR concept, and serve to optimize SDR structure and improve its conventional engineering design, especially for ensuring the slab punching shear resistance.

Wavelet identification for the abnormal seismic wave component of rock burst

  • Yunliang Tan;Wei Yan;Tongbin Zhao
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.437-440
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    • 2003
  • As we know, roof is composed of heterogeneous rock. When roof fractures, a large amount of energy would be released in the form of seismic wave. How to identify the abnormal signal of seismic wave is a much difficult problem, there are many methods used usually, such as Fourier Transformation, filter technique etc., but abnormal signal can't be recognized accurately. In this paper, multi-resolution wavelet technique is used to identify the first and second variation point, based on the Lipschitz $\alpha$. A living example analysis shows, multi-resolution wavelet technique can identify the abnormal signal of seismic wave effectively in different scale, and the omen of roof fall can be grasped in order to forecast the roof fall accurately. It provides a new idea for the predication of catastrophe on rock mechanics and engineering.

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Development of Rock Slope Survey and Analysis System using GIS

  • Park, H. J.;Chang, B. S.;Lee, S.
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.144-146
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    • 2003
  • Techniques for rock slope management and assessment must be developed for the prevention and mitigation of rock fall hazards. To enable this, the rock discontinuity such as fault and joint data must be surveyed, analysed and managed. For this, the discontinuities were detected by automatic and semi-automatic method using DEM and ortho-rectified image of rock slope and the rock slope analysis and management system was developed using GIS. Using the system, slope locations and discontinuities data were constructed to spatial database. The system is consist of ‘Data Management’, ‘Rock Slope DB’, ‘Basic Information’, ‘Image Processing’, ‘Image Analys ing’, ‘Edit’, ‘View’, ‘Theme’, ‘Graphic’, ‘Window’ and ‘Help’. The system was developed using avenue of ArcView 3.2.

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Geomorphic Features of ${\check{O}}rumkol$(Frozen Valley) Area (Kyungnam Province, South Korea) - Mainly about Talus - (경남 밀양 얼음골 일대의 지형적 특성 -Talus를 중심으로-)

  • Jeon, Young-Gweon
    • Journal of the Korean association of regional geographers
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    • v.3 no.1
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    • pp.165-182
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    • 1997
  • The aim of this paper is to clarify geomorphic features on talus within ${\check{O}}rumkol$ and the origin of ${\check{O}}rumkol$. ${\check{O}}rumkol$ is located in Milyang of Kyungnam province, in South Korea. ${\check{O}}rumkol$ is good area to study talus. because it is characterized by following three geomorphic landscapes : free face surrounding ${\check{O}}rumkol$ ; ${\check{O}}rumkol$ with deep and wide valley floor ; lots of taluses typically developing within ${\check{O}}rumkol$. The main results can be summarized as follows: 1) The origin of ${\check{O}}rumkol$ may be suggested two assumptions : one is that its origin have been resulted from intrusion structure(intrusive rock might capture less resistant rock as tuff) ; the other is that its origin have been resulted from volcanic depression after intrusion or eruption. But these assumptions are not obvious. therefore more geological evidences will be supplemented after this 2) The characteristics of ${\check{O}}rumkol$ talus (1) Pattern ${\check{O}}rumkol$ taluses are tongue-shaped or cone-shaped in appearance. They are $50{\sim}200m$ in length and the range of the maximum width from 25 to 115m and one of their mean slope gradient from 32 to $36^{\circ}$ (2) Origin ${\check{O}}rumkol$ taluses have been formed under periglacial environment in the last glacial age and they are classified into rock fall talus type, considering in conjunction with the shape, hardness, sorting, weathering conditions of constituent debris. (3) The stage of landform development ${\check{O}}rumkol$ talus slope profiles are mainly concave slope. This concave slope type was eventually caused by talus creep at the lower end of the talus. That means new additions of debris from the free face have virtually ceased and there is no evidence of recent motion in the deposit. Now it is predominant that vegetation cover is gradually increasingly. Therefore ${\check{O}}rumkol$ taluses appear to be relict form stage. at present.

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A study on Orientation and Morphology of clasts in Rockfall Talus in the Sukam area, Bukpyoung-eup, Gangwon-do, South Korea (테일러스 역의 방향성 및 형태 분포에 대한 연구 - 강원도 정선군 북평읍 숙암리 지내 사면을 중심으로 -)

  • Kim, Seung-Hyun;Koo, Ho-Bon;Baek, Yong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.469-474
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    • 2003
  • Talus topography is that rock clasts that is weathered is accumulated dropping in steep slope to action of gravity. Rock fall talus is formed by the accumulation of rock debris falling as individual particles from a cliff. If the collapse is produced in talus slope, it will be possible the loss of manpower and country. Despite correct access about talus is required, domestic research was scientific access about talus short. The aim of the present study is to review and compare fabric data derived from rock fall talus about orientation, distribution and morphology in Sukam area. These deposits tend to have approximately equal amounts of clasts oriented parallel and perpendicular to the dip direction of the slope. And, platy-shaped clasts dominate the proximal and intermediate parts of the talus, whereas blocky-shaped clasts is more common in the distal part.

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Characteristics of Roadside Cut-Slopes Failures along the 46th National Highway (남양주-춘천(국도 46 호선)간 도로절개면 붕괴 특성 고찰)

  • 구호본;정의진;박성욱
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.527-534
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    • 2000
  • 136 cut slopes which extends from Namyangju to Chunchon city along the 46th national highway were investigated to analyze the influence factors affecting slope instability. Geologic and geotechnical conditions were examined and the detailed investigation were carried out for fifty five failed slopes. failure mode (wedge failure, planar failure, circular failure, sheet eroison and rock falls) are examined with respect to slope inclination, rock type, weathering grade and discontinuity patterns. It is suggested that the failure modes and their dimensions have relations to the morphology and geologic conditions of the slopes. Wedge failure has highest is the most frequent failure mode and falls, sheet erosions, planar failures and circular in descending order of failure percentage. Wedge failure is most dominant failure type over all lithology except quartzite formation. In slopes of well foliated and banded gneiss, failure ratio of wedge is up to 50% ca. Failure ratio(number of rock fall/number of total failure) of rock fall increases with increase fo slope inclinations and decrease of weathering grade. Dimension analyses of failed slopes shows wedge and circular failure has higher value of D/L and D/H than planar failure and sheet erosion.

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Failure Characteristics of Cut Slopes of Shale in Ky ngsang Basin (경상분지 셰일 지역에서의 절토사면 파괴 특성)

  • 김경석;유병옥;이상돈
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.11b
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    • pp.103-114
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    • 2002
  • Stability of cut-slope is considered to have a deep relationship with rock types since rock has its own engineering and geological characteristic such as shear strength, durability, weathering profile, geological structures. Therefore, analysis of geological and engineering characterisics of rock mass is essential for the evaluation of rock slope stability This paper introduces the statistical data of slope failure cases which was collected from highway slopes constructed in sedimentary rock mainly of shale in Ky ng-sang Basin. Primary failure feature in this area is planar failure along the bedding regardless of slope geometry. Even a disasterous slope failure case due to the thick clay layer between the beddings was reported. Failures and rock fall were reported to ocurred frequently after the completion of cutting due to the weathering, so long-term slope stability should be considered as a important factors in design.

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Development of Integrated Slopes Database System for Real-Time Global Web Service (광역 실시간 웹 서비스를 위한 통합 사면 데이터베이스 시스템 개발)

  • Lee, Kyu-Woong;Tscha, Yeong-Whan;Lee, Seung-Ho
    • The Journal of the Korea Contents Association
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    • v.10 no.6
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    • pp.471-479
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    • 2010
  • The main contribution of this paper is to propose the integrated database schema from several research projects included in "The Next Generation New Technology for Rock-falling and Landsliding Project". Furthermore this paper describes the development of integrated standard database system for the slopes databases. We also develop and implement the global real time web service system in order to provide one-stop data service for the slopes. In this paper, the new integrated database paradigm for rock-fall and landsliding data is designed and proposed and also data management system is developed based on the global web service system.

Evaluation of Cave-in Possibility of a Shallow Depth Rock Tunnel by Rock Engineering Systems and Uumerical Analyses (암반공학시스템과 수치해석을 이용한 저심도 암반터널에서의 붕락 발생 가능성 평가)

  • Kim, Man-Kwang;Yoo, Young-Il;Song, Jae-Joon
    • Tunnel and Underground Space
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    • v.19 no.3
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    • pp.236-247
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    • 2009
  • Overpopulation has significantly increased the use of underground spaces in urban areas, and led to the developments of shallow-depth underground space. Due to unexpected rock fall, however, it is very necessary to understand and categorize the rock mass behaviors prior to the tunnel excavation, by which unnecessary casualties and economic loss could be prevented. In case of cave-in, special attention should be drawn since it occurs faster and greater in magnitude compared to rock fall and plastic deformation. Types of cave-in behavior are explained and categorized using seven parameters - Uniaxial Compressive Strength (UCS), Rock Quality Designation (RQD), joint surface condition, in-situ stress condition, ground water condition, earthquake & ground vibration, tunnel span. This study eventually introduces a new index called Cave-in Behavior Index (CBI) which explains the behavior of cave-in under given in-situ conditions expressed by the seven parameters. In order to assess the mutual interactions of the seven parameters and to evaluate the weighting factors for all the interactions, survey data of the experts' opinions and Rock Engineering Systems (RES) were used due to lack of field observations. CBI was applied to the tunnel site of Seoul Metro Line No. 9. UDEC analyses on 288 cases were done and occurrences of cave-in in every simulation were examined. Analyses on the results of 288 cases of simulations revealed that the average CBI for the cases when cave-in for different patterns of tunnel support was estimated by a logistic regression analysis.