• Title/Summary/Keyword: Ground collapses

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Review on Current Status on Mine Reclamation Policies of 9 Countries represented by International Symposium (광해방지 국제심포지엄 발표사례로 본 국가별 광해 및 복구현황과 정책)

  • Lee, Seung Ah;Yang, In Jae
    • Journal of the Korean Society of Mineral and Energy Resources Engineers
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    • v.55 no.6
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    • pp.546-552
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    • 2018
  • Although there are differences in the history of mining development by country, geographical conditions, and economic status, there are various problems such as water pollution caused by acid mine drainage from past mine development, soil and water pollution caused by mine tailing, and landslides caused by slope failure. Thus, human life is threatened by ground subsidence caused by collapses. Some countries have technology and legal systems that are different from those of others. In countries where mine reclamation is underway, or has to begin, there is a need for institutional arrangements and technical support. Countries trying to start mine reclamation require help from the international community. Technically and institutionally advanced nations need to recover from mine reclamation through cooperation with countries that are beginning to undertake reclamation.

Precision Improvement Methodology of Geotechnical Information through Outlier Analysis (이상치 분석을 통한 3차원 지반정보 정밀도 향상 방안)

  • Lee, Boyoung;Hwang, Bumsik;Kim, Hansaem;Cho, Wanjei
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.2
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    • pp.23-35
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    • 2018
  • Recently, ground disasters such as road collapses and cavities have been frequently occurred in Seoul and downtown areas. As a result, studies on the integrated underground space map is underway as a government's solution. On the other hand, the geotechnical information underlying the integrated underground space map has been being built with more than 220 thousands borehole DB informations through the Integrated DB Center of National Geotechnical Information. To build a three-dimensional integrated underground space map based on the geotechnical information, the reliability of the geotechnical information should be verified by analyzing and evaluating the precision of the geotechnical information. Thereby, studies were conducted on the precision verification and evaluation of the constructed geotechnical information. Thereafter, it has been reviewed how to utilize geotechnical information in addition to analyzing the precision of the geotechnical information in order to visualize three dimensions in geotechnical information. As a further step to the practical DB application, a module is suggested in this study to improve the precision of geotechnical information for establishing reliable three dimensional integrated underground space maps based on the previous research results.

In situ investigations into mining-induced overburden failures in close multiple-seam longwall mining: A case study

  • Ning, Jianguo;Wang, Jun;Tan, Yunliang;Zhang, Lisheng;Bu, Tengteng
    • Geomechanics and Engineering
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    • v.12 no.4
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    • pp.657-673
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    • 2017
  • Preventing water seepage and inrush into mines where close multiple-seam longwall mining is practiced is a challenging issue in the coal-rich Ordos region, China. To better protect surface (or ground) water and safely extract coal from seams beneath an aquifer, it is necessary to determine the height of the mining-induced fractured zone in the overburden strata. In situ investigations were carried out in panels 20107 (seam No. $2-2^{upper}$) and 20307 (seam No. $2-2^{middle}$) in the Gaojialiang colliery, Shendong Coalfield, China. Longwall mining-induced strata movement and overburden failure were monitored in boreholes using digital panoramic imaging and a deep hole multi-position extensometer. Our results indicate that after mining of the 20107 working face, the overburden of the failure zone can be divided into seven rock groups. The first group lies above the immediate roof (12.9 m above the top of the coal seam), and falls into the gob after the mining. The strata of the second group to the fifth group form the fractured zone (12.9-102.04 m above the coal seam) and the continuous deformation zone extends from the fifth group to the ground surface. After mining Panel 20307, a gap forms between the fifth rock group and the continuous deformation zone, widening rapidly. Then, the lower portion of the continuous deformation zone cracks and collapses into the fractured zone, extending the height of the failure zone to 87.1 m. Based on field data, a statistical formula for predicting the maximum height of overburden failure induced by close multiple seam mining is presented.

Development and Verification of A Module for Positioning Buried Persons in Collapsed Area (붕괴지역의 매몰자 위치측위를 위한 모듈 개발 및 검증)

  • Moon, Hyoun-Seok;Lee, Woo-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.427-436
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    • 2016
  • Due to disasters such as earthquakes and landslides in urban areas, persons have been buried inside collapsed buildings and structures. Rescuers have mainly utilized detection equipment by applying sound, video and electric waves, but these are expensive and due to the directional approaches onto the collapsed site, secondary collapse risk can arise. In addition, due to poor utilization of such equipment, new human detection technology with quick and high reliability has not been utilized. To address these issues, this study develops a wireless signal-based human detection module that can be loaded into an Unmanned Aerial Vehicle (UAV). The human detection module searches for the 3D location for buried persons by collecting Wi-Fi signal and barometer sensors data transmitted from the mobile phones. This module can gain diverse information from mobile phones for buried persons in real time. We present a development framework of the module that provides 3D location data with more reliable information by delivering the collected data into a local computer in the ground. This study verified the application feasibility of the developed module in a real collapsed area. Therefore, it is expected that these results can be used as a core technology for the quick detection of buried persons' location and for relieving them after disasters that induce building collapses.

A Study on the Assessment of Safety Factor of Tunnels (터널의 안전율 평가 기법에 관한 연구)

  • 박종원;박연준;유광호;이상돈
    • Tunnel and Underground Space
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    • v.14 no.5
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    • pp.327-338
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    • 2004
  • The purpose of this research is to establish a concept of the factor of safety of tunnels which is a quantitative estimate of the stability of tunnels. Based on this concept, a numerical technique which calculates the factor of safety of tunnels was developed. To obtain the safety factor of a tunnel, the strength reduction technique in which a series of analyses are repeated with reduced ground strength until the tunnel collapses were employed. With this technique, the failure plane, as well as the factor of safety, can be obtained without prescribing the trial failure plane. Analyses were conducted with FLA $C^{2D}$(ver3.3), a geotechnical analysis program which is based on the finite difference method. From the result, the location of plastic zones, the maximum convergence and the maximum stress generated in the support system were also analyzed. The result shows that factors of safety are higher for the 1st and 2nd rock classes, and lower for the lower rock classes. Furthermore, factor of safety is higher when $K_{0}$ =0.5 compared to at in case of $K_{0}$ =2.0. Through this research, it is found that the factor of safety defined in this research can be used as a good quantitative index representing the stability of tunnels. Also, close examination of the results can help adjustment of the quantity and location of additional supports.s.

Development of a Slope Condition Analysis System using IoT Sensors and AI Camera (IoT 센서와 AI 카메라를 융합한 급경사지 상태 분석 시스템 개발)

  • Seungjoo Lee;Kiyen Jeong;Taehoon Lee;YoungSeok Kim
    • Journal of the Korean Geosynthetics Society
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    • v.23 no.2
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    • pp.43-52
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    • 2024
  • Recent abnormal climate conditions have increased the risk of slope collapses, which frequently result in significant loss of life and property due to the absence of early prediction and warning dissemination. In this paper, we develop a slope condition analysis system using IoT sensors and AI-based camera to assess the condition of slopes. To develop the system, we conducted hardware and firmware design for measurement sensors considering the ground conditions of slopes, designed AI-based image analysis algorithms, and developed prediction and warning solutions and systems. We aimed to minimize errors in sensor data through the integration of IoT sensor data and AI camera image analysis, ultimately enhancing the reliability of the data. Additionally, we evaluated the accuracy (reliability) by applying it to actual slopes. As a result, sensor measurement errors were maintained within 0.1°, and the data transmission rate exceeded 95%. Moreover, the AI-based image analysis system demonstrated nighttime partial recognition rates of over 99%, indicating excellent performance even in low-light conditions. Through this research, it is anticipated that the analysis of slope conditions and smart maintenance management in various fields of Social Overhead Capital (SOC) facilities can be applied.