• Geomechanics and Engineering
• /
• 제17권4호
• /
• pp.375-383
• /
• 2019

In underground retreating longwall coal mining, hard roof collapse is one of the most challenging safety problems for mined-out areas. Identifying precursors for hard roof collapse is of great importance for the development of warning systems related to collapse geohazards and ground control. In this case study, the Xinhe mine was chosen because it is a standard mine and the minable coal seam usually lies beneath hard strata. Real-time monitoring of hard roof collapse was performed in longwall face 5301 of the Xinhe mine using support resistance and microseismic (MS) monitoring; five hard roof collapse cases were identified. To reveal the characteristics of MS activity during hard roof collapse development and to identify its precursors, the change in MS parameters, such as MS event rate, energy release, bursting strain energy, b value and the relationships with hard roof collapse, were studied. This research indicates that some MS parameters showed irregularity before hard roof collapse. For the Xinhe coalmine, a substantial decrease in b value and a rapid increase in MS event rate were reliable hard roof collapse precursors. It is suggested that the b value has the highest predictive sensitivity, and the MS event rate has the second highest.

• Geomechanics and Engineering
• /
• 제21권1호
• /
• pp.23-33
• /
• 2020

An advancing cutting roof for gob-side entry retaining with no-pillar mining under specific geological conditions is more conducive to the safe and efficient production in a coalmine. This method is being promoted for use in a large number of coalmines because it has many advantages compared to the retaining method with an artificial filling wall as the gateway side filling body. In order to observe the inner structure of the gateway cutting roof and understand its stability mechanism, an equivalent material simulation experiment for a coalmine with complex geological conditions was carried out in this study. The results show that a "self-stabilization bearing structure" equilibrium model was found after the cutting roof caving when the cut line deviation angle was unequal to zero and the cut height was greater than the mining height, and the caving roof rock was hard without damage. The model showed that its stability was mainly controlled by two key blocks. Furthermore, in order to determine the optimal parameters of the cut height and the cut line deviation angle for the cutting roof of the retaining gateway, an in-depth analysis with theoretical mechanics and mine rock mechanics of the model was performed, and the relationship between the roof balance control force and the cut height and cut line deviation angle was solved. It was found that the selection of the values of the cut height and the cut line deviation angle had to conform to a certain principle that it should not only utilize the support force provided by the coal wall and the contact surface of the two key blocks but also prevent the failure of the coal wall and the contact surface.

• 보존과학회지
• /
• 제22권
• /
• pp.15-30
• /
• 2008

공주 단지리 3지구 출토 와관묘를 구성하는 기와와 고토양을 대상으로 재료과학적 연구방법을 적용하여 기와의 제작기법 및 원료의 산지추정을 통해 와관묘의 성격을 검토하였다. 기와는 모두 암키와로서 백제기와의 특징을 가진 연질 및 경질 기와이며 표면과 단면에 유상조직을 가지고 있다. 또한 기와의 광물학적 및 지구화학적 분석 결과, 태토는 주변토양을 이용하였으며, 제작과정에서는 토양의 거정질 석영 등을 제거하여 정제된 상태의 태토를 사용하였을 것으로 추정된다. 소성온도 추정결과, 일부 경질 기와는 $940{\sim}1,020^{\circ}C$에서, 연질 기와는 $700{\sim}900^{\circ}C$에서 소성한 것으로 판단된다. 기와들은 오랜 기간 매장환경의 영향을 받아 유기물 함량이 높고 인체조직의 필수 미량원소들이 토양에 비해 농집되어 있다. 따라서 이 기와들은 시신을 직접 매장하는 일차장으로서의 역할을 수행하였을 것으로 판단된다. 또한 건물지에 사용한 기와와 크기, 형식, 제작방법이 유사하여 당시 사용되던 암키와를 매장용으로 사용하였을 것으로 해석된다.

• Geomechanics and Engineering
• /
• 제21권4호
• /
• pp.371-377
• /
• 2020

There are currently three common methods for selecting excavation supports in Polish hard coal mines. While many factors are considered when choosing appropriate support, these do not include layering or cracking in the excavation ceiling. Although global classifications of rock mass are rarely used in hard coal mines, they are utilised much more frequently during the construction of underground structures such as tunnels. Mining classifications of rock mass have been developed (e.g., in Germany) and they rely on a number of factors but are often related to local mining and geological conditions. This paper discusses the selected findings of a study carried out on seven excavation sites with diverse mining and geological characteristics. Based on the collected data, two indicators were developed to describe rock mass quality. The first indicator is referred to as the roof lithology index WL and describes the quality of the excavation roof in terms of its layering and lithology. The second indicator is the crack intensity factor n and represents the amount of cracks in an excavation's roof. The correctness of the developed indicators was supported by reliable data from the excavation in which the designed support did not fulfill its task but was changed at a later stage, after calculating the proposed indicators.

• Journal of the Korean Wood Science and Technology
• /
• 제36권1호
• /
• pp.1-11
• /
• 2008

안성 석남사 영산전에 쓰인 주요 목부재의 수종을 식별하기 위하여 기둥, 창방, 대들보, 서까래, 청판 등 총 95점에 대하여 조사하였다. 수종은 소나무류(경송류), 외래산 소나무류, 느티나무, 은행나무, 감나무속, 배나무속, 참나무속의 상수리나무류 등 7 수종이 식별되었다. 기둥에서는 소나무류(경송류) 8점, 느티나무 1점, 배나무속 1점이 확인되었다. 추녀에서는 은행나무 2점과 느티나무 2점, 대들보에서는 소나무 1점과 느티나무 1점이 나왔다. 주심도리는 2점 모두 상수리나무류이었고, 서까래에서는 은행나무 1점과 외래산 소나무류 1점을 제외하고는 나머지는 소나무류인 것으로 밝혀졌다. 적심목에서 느티나무 1점과 감나무속 1점이 나왔다. 다른 부재는 소나무류가 대부분이었다. 서까래에서 나온 외래산 소나무 1점은 해방 이후 영산전 수리 시 사용된 것으로 추정되었다. 소나무류 이외에 다양한 수종의 목재가 사용된 것은 사찰 인근에서 쉽게 구할 수 있는 수종들을 이용하였기 때문인 것으로 사료된다.

• 한국주거학회논문집
• /
• 제9권3호
• /
• pp.79-86
• /
• 1998

The image of architecture changes with its age. In spite of its age, traditional architecture still looks like beautiful. This study is to define the change of image for traditional architecture with its appearance. I-se Jingu, Japan was selected for subject architecture because of its new and old one were in same site. In part 1, the image was considered with six scales: gorgeous-modest, strict-loose, hard-soft, orderly-disorder, new-old, and beautiful-ugly. The image of strict-loose, hard-soft, orderly-disorder related with the style, roof materials and damage of materials. Respectively the image of gorgeous-modest is relevent to "beautifulness", regardless of its age.f its age.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.379-382
• /
• 1997

This paper introduces a new vision technique for extracting roof edges of polyhedra having specularly reflecting surfaces. There have been many previous works on object recognition using edge information. But they can not be applied to specular objects since it is hard to acquire reliable camera images of specular objects. If there is a method which can extract the edges of specular objects, it is possible to apply edge-based recognition algorithms to specular objects. To acquire the reliable edge images of specular objects, scanned double pass retroreflection method is proposed, whose main physical characteristic is curvature-sensitive. This utility of the physical characteristic is motivated by the idea that roof edges can be characterized as local surfaces of high curvature. In this paper, the optical characteristics of double pass retroreflection are discussed and a series of simulation studies are performed to verify and analyze the sensor characteristics. The results from a series of simulations show the effectiveness of the proposed method.

• 대한지리학회지
• /
• 제19권
• /
• pp.41-51
• /
• 1979

Since 1971 when the nation wide 'New Community' movement was launched to improve rural standards of living, dol and thatched-roof houses have been reshaped or removed, thereby making it hard to find time-honored people's living structures in the countryside. Since 1977, the improvement work of rural houses has started throughout the country, so many new rural residences have been constructing along the highway, main roads, railways and around the sightseeing area, New rural houses do not show, for the most part, the traditional architectural style and the nation's unique conventional ways of living. The writer tried to find solutions to the problems derived from improvement work of rural residence, in a comparative method of traditional rural houses and newly constructed rural ones. The greater part of new rural houses' types, painting colors, and fence types had been recommended by provincial administrative trative officials. Officials recommended them to the farmer with their standards, which did not consider farmer's convenience of traditional way of life, but a fine sight from the highways or railways. Korea's three basic roof types are the HAPKAK roof (gabled and hipped), the UCHINKAK roof(hipped), and the BAKKOONG roof(gabled). However, the gabled roof houses, having their entrance on the gabled side, are found more ofter in new rural village. As mentioned above, architectural style is not harmonious with the topography and climate i Korea, because it is not Korean traditional type, but one of the western styles. And new rural house plans are inconvenient in the conservation rural family system, because of the same category with urban houses plans. Other problems derived from ton-traditional architecture style are roof painting in 4-5 colors in a new village, types of wall and fence, and attached building in the site.

• 한국공간구조학회논문집
• /
• 제19권4호
• /
• pp.103-110
• /
• 2019

The cable-based retractable membrane roof makes it impossible to maintain its shape and stiffness during driving process, unlike the hard-type retractable roof. Consequently, monitoring using a relatively simple wireless video transmission device is required. However, since video data has a bigger transmission rating than other monitoring data in terms of the structure velocity or acceleration, there is a need to develop transmission device that is easy to install and entails low maintenance cost. This paper studies on a real-time video transmission system for monitoring the cable-based retractable membrane roof while driving. A video transfer software, using the mobile network, is designed and the embedded system is constructed. Ultimately, the data transmission server is tested. Connecting a trolley to the system allows testing of the validity and efficiency of the developed system through the video data transmitted in the driving process. Result of the test shows that the developed system enables multi-device data transfer with monitoring via the mobile network.

• 한국환경복원기술학회지
• /
• 제8권6호
• /
• pp.34-44
• /
• 2005

The objective of this study is to analyze the thermal properties of various green roof type. The experimental districts, have different soil thickness, soil type, the existence of module and the different kinds of vegetation, had installed. A measurement was conducted in Seoul University to investigate the thermal impacts of rooftop greening. The measurement point of temperature were 30, located in soil surface, middle of the soil layer, under the module, hard surface and soffit surface of each experimental district. The experimental investigation lasted from 6th August to 29th August, a total of 24 days. The results showed that green roof can contribute thermal benefits by soil and vegetation and reduce building energy consumption by a role of insulation. It's also better to make soil thickness over 20cm and various vegetation that should be more effective. The district installed only soil also could be effective for reducing the temperature of roof surface. Therefore, the increase of soil thickness and various vegetation could reduce more temperature of roof surface and building energy consumption. Also, it's helpful to reduce temperature that plant coverage rate be raised.