옹벽 및 사면의 안정성 검토 사례

백승철 安東大學校 工業技術硏究所 2001 공업기술연구논문집 Vol.8 No.1

옹벽과 사면은 토지의 이용을 최적으로 활용하기 위하여 축조되는 토목구조물이다. 본 구조물이 붕괴될 경우 큰 피해를 입게되므로 안전한 설계 및 시공이 이루어져야 한다. 본 논문에서는 현재 시공중인 안기동 성진 임대아파트의 옹벽과 사면의 안정성 검토를 실시한 과정 및 결과 정리 통하여 효율적인 옹벽 및 사면의 안정성 검토 방법을 제시한다. Retaining Walls and Slopes are the civil engineering structures which are commonly designed and constructed for the optimum use of land space. Because of the potential danger of catastrophic disasters in the rare cases of accidental collapses of these types of structures, they must be designed and constructed with extreme care and with safety first in mind. This paper reports a stability evaluation result of the retaining walls and slopes constructed for the Sung-Jin Lease Apartment in An-Gi-Dong, Andong. A new effective method of stability evaluation is also suggested based upon these study results.

절토사면 안전성 검토에 관한 연구

백승철 安東大學校 工業技術硏究所 1999 공업기술연구논문집 Vol.6 No.1

안동의 한 지역에서 사면을 절토하여 부지정리를 하는 과정 중 절토사면의 일부구간이 붕괴되었고, 또한 추가적인 사면 붕괴가 예측되어 사면 안정성 검토를 수행하였다. 사면 안정상 검토를 실시하기 위하여 지질조사, 현장 암석강도시험 및 전단시험을 실시하고, 설계 및 시공 현황을 분석하였다. 지질조사와 현장시험 결과를 이용하여 사면 안정성 검토 분석 자료를 얻었으며, 사면 안정해석은 평사투영법과 한계 평형해석을 실시하였다. 그 결과 사면의 추가 붕괴가 일어날 것으로 판단되었으며, 현장 상황에 적당한 대책공법을 제시하였다. The purpose of this paper is to examine the possibility of slope collapse in the slope cutting process, particularly at an actual site in Andong. Based on geological site investigation and field test, stability analysis of slope was performed in conjunction with stereo-graphic projection and limit equilibrium methods. Additionally, initial design and construction procedure was critically evaluated. The results show that current slope cutting works may lead directly to slope collapse under the land situations. As a result, a proper countermeasure against slope failure is suggested in a supplementary manner.

암반사면의 안정성 평가-도해법

백승철 안동대학교 기초과학연구소 1993 基礎科學 硏究論文集 Vol.4 No.1

The stability assessment of rock slope in preliminary site investigations (graphical method) is used steronet that based on sterographic projection. The conventional steronet method is combined daylight envelope with friction cone and toppling envelope. Use of overlays with the plotted and contoured field data considerably simplifies stability assessment. In this paper it is presented that the new stability assessment of rock slope is considered several geometric failure conditions.

地盤改良工法 選定에 관한 小考

백승철 안동대학교 기초과학연구소 1991 基礎科學 硏究論文集 Vol.2 No.1

It is a complex problem to appropriately select soil improvement methods because the engineering judgement of soil improvement must be considered on the composite conditions of ground, especially in the soft ground. Hence, the optimum methods to improve the weak soils is essentially selected on the basis of the complete site investigation, the knowledge of their characteristics and the effects of the existing environments. Therefore, in the present study, the principles and characteristics of soil improvement methods proposed till now were analysed, and the guideline of the selection of the optimum soil improvement method was presented.

흙의 함수비 측정시간 단축에 관한 연구

백승철 安東大學 1990 安東大學 論文集 Vol.12 No.1

An Experimental research was performed to study the estimation of the microwave drying technique for rapid moisture content determination. Soils used in the tests were sand and clay. Conventional and microwave oven moisture content test results were compared and differences between two measurements were analyzed throughout the linear regression analyses. Empirical equations for microwave exposure times needed to produce moisture contents comparable to those obtained by the conventional oven were established by the polynomial regression analyses. Based on these equations, microwave oven testing method for determination of the water contents of granular soils and cohesive soils was presented, together with a determinated method.

레디-믹스트 콘크리트 타설이 가능한 고강도 콘크리트의 배합비 결정

백승철,박영식 安東大學 1997 安東大學 論文集 Vol.19 No.1

The high-strength ready-mixed concrete(HS-RMC) which is obtained by adding some mixtures has many differences in mechanical properties, mix-proportions, etc. to normal-strength concrete. Recently, the necessity and the importance of high-strength concrete is emphasized, because the high-strength concrete has been used in constructions of various structures frequently. Until now, the studies on characteristics and behaviors of high-strength concrete have been carried out only through mostly laboratory tests, instead of considering actual construction situation. Therefore, the economical and the stable aspects for high-strength ready-mixed concrete construction should be guaranteed with commonly used materials for concrete and without supervising various conditions of in-situ construction. In this paper, mix-proportions for manufacturing the high-strength ready-mixed concrete which have compressive strengths of 400, 550 and 700kg/㎠ at 28-day are presented by priliminary and actual mix-designs.

저수지 붕괴의 원인 및 피해분석 : 공실지를 중심으로

신사철,백승철 安東大學校 工業技術硏究所 2000 공업기술연구논문집 Vol.7 No.1

재해가 발생하면 신속한 피해복구 대책을 수립하기 위해서는 무엇보다 먼저 재해지역에 대한 신속하고 정확한 조사가 실시되어야 한다. 본 연구는 저수지 붕괴에 따른 원인분석을 체계적으로 실시하여 특히 수해발생시 수행되어야 분석의 기준을 제시하고 자 한다. 경상북도 안동시에 위치한 공실 지는 2000년 8월 26일 호우로 인하여 8월 27일 01:00 (추정시각)에 우안 여수로에서 좌안 부분 상 약 5m, 하부 약 3m, 정도가 유실되어 농경지와 가옥의 침수피해가 발생하였다. 이 붕괴사상을 대상으로 붕괴에 따른 피해 및 원인 분석을 현장조사와 수문해석 및 토양 및 지질분석을 통하여 실시하였다. 수문해석 및 흔적조사에서도 저수지 제방의 월류의 가능성은 적으며, 지속적인 여수로와 저수지 제체 연결부로 침투가 이루어져 저수지 제체가 불안정한 상황 하에 갑작스러운 호우로 인하여 침투량이 증가하여 과잉공극수압의 증가로 인하여 파괴가 발생한 것으로 판단된다. To prepare measures for dealing with disasters, the exact investigation for disaster area have to take effect. In this study, the factors leading to reservoir break are analyzed, and set a standard analysis in carrying out reservoir break. The Kongsil reservoir located in Andong City was breaked in a localized torrential downpour at Aug. 27, 2000. As the result of the Kongsil reservoir break, submerged farm land and house occurred in the downstream area. The damage analysis caused by Kongsil reservoir break was performed through field investigation, hydrologic and geological analysis. The reservoir bank have been unstable by infiltration into joined area of spillway and reservoir embankment. Consequently, The reason of the Kongsil reservoir break is supposed that a sudden increase of infiltration into unstable embankment led to increase of excess pore pressure.

한국인 부정교합자의 하악 치열궁의 크기와 형태

이성준,백승학,김상철,국윤아 대한치과교정학회 2005 대한치과교정학회지 Vol.35 No.1

본 연구의 목적은 한국인 부정교합자에서 하악 치열궁간의 형태적 차이를 알아보고자 하였다. Ⅰ급 114명. Ⅱ급 119명, Ⅲ급 135명의 부정교합자를 대상으로 하악 모형의 교합면을 복사한 후 13개의 접촉점 중에서 가장 협측면으로 위치한 부분을 digitize 하였고 각 치아의 브라켓 위치에 해당하는 점을 하악치아의 두께에 의거하여 4개의 선계측과 2개의 비율을 측정하였다. 치열궁의 형태는 square ovoid, tapered형으로 분류하여 그 빈도를 조사한 결과 Angle 분류와 남녀 성별에 따른 특별한 치열궁 형태가 존재하지 않았으나, 특정 치열궁 형태의 빈도는 Angle 분류에 따라 다르게 나타났다. 치열궁 크기의 계측항목에서는 대구치간 폭경에서만 남녀 성별 차이를 보였으며, 치열궁 크기에 있어서 Ⅰ급과 Ⅲ급, Ⅱ급 부정교합군간에는 유의한 차이가 있었다. 치열궁 형태의 분포는 Ⅰ급과 Ⅲ급 부정교합군에서는 square, ovoid, tapered 형태 순이었고, Ⅱ급 부정교합군은 square, tapered ovoid 형태 순이었다. 치열궁 형태의 빈도분포에 있어서는 남녀간의 차이는 없었다. The purpose of this study was to clarify morphological differences among mandibular dental arch forms in Korean malocclusion patients. The sample in this study consisted of 114 Class Ⅰ, 119 Class Ⅱ, and 135 Class Ⅲ malocclusion cases. The most facial portions of 13 proximal contact areas were digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on the data of the mandibular tooth thickness. Four linear and two proportional measurements were undertaken. The dental arches were classified into square, ovoid, and tapered forms to compare the frequency distributions. Our results suggested that there was no single arch form specific to any particular Angle classification or sex. It appeared to be the frequency of a particular arch form that varies among the Angle classifications. In comparison of arch measure between male and female, there was no statistical difference except in the intermolar width. In comparison of arch size measurements among the different Angle classifications, there were statistically significant differences between Class Ⅰ and Class Ⅲ malocclusion groups and between Class Ⅱ and Class Ⅲ malocclusion groups. In comparison of frequency distribution of arch forms in Class Ⅰ and Ⅲ malocclusion groups, the square form demonstrated the highest distribution followed by the ovoid and tapered forms in that order. In the Class Ⅱ malocclusion group, the square form showed the highest distribution, followed by the tapered and ovoid forms in that order. There was no statistical difference in the frequency distribution of arch forms between male and female groups.

초기 진동 특성치가 측정되지 않은 캔틸레버 보의 손상 추정 방법에 관한 연구

문환두,백승철 安東大學校 工業技術硏究所 1996 공업기술연구논문집 Vol.3 No.1

Most civil engineering structures are apt to experience structural damages over their service lives caused by adverse loadings. Accumulation of structural damages over a long period time might cause catastrophic structural failure. Therefore, maintenance and retrofitting of existing structures is essential for assuring the safety of the existing structures. The damage detection algorithm must be exact and reliable. There have recently been attempts to evaluate the structural damage utilizing the experimentally measured response data. But the baseline modal responses were required to evaluate the structural damage. The purpose of this paper is to present the damage detection algorithm for structures without baseline modal responses. Natural frequencies of a structure with a transverse surface crack extending uniformly along the width is measured experimentally. Using only the natural frequencies of a damaged structure, it has been found that the location and degree of damage are reasonably determined. The damage detection algorithm was applied to identify a crack in a cantilever beam.

레진 계열 근관봉함재 Adseal의 세포독성에 관한 연구

김희정,백승호,이우철,박한수,배광식 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.6

The properties of ideal root canal sealers include the ability of sealing the total root canal system and no toxic effects to periradicular tissues. Cytotoxicity test using cell culture is a common screening method for evaluation of the biocompatibility of root canal sealers. The purpose of this study was to investigate the cytotoxic effect of newly developed resin-based sealer (Adseal 1, 2, and 3) comparing with those commercial resin-based sealers (AH26 and AH Plus), ZOE-based sealers (Tubliseal EWT, Pulp Canal Sealer EWT) and calcium hydroxide based sealer (Sealapex). An indirect contact test of cytotoxicity by agar diffusion was performed according to the international standard ISO 10993-5. L929 fibroblast cells were incubated at 37℃ in humidified 5% CO₂-containing air atmosphere. The freshly mixed test materials were inserted into glass rings of internal diameter 5 ㎜ and height 5 ㎜ placed on the agar. After the 24 hrs incubation period, the decolorization zones around the test materials were assessed using an inverted microscope with a calibrated screen. A Decolorization Index was determined for each specimen. Adseal 1, 2, and 3 did not exert any cytotoxic effects, whereas AH26, AH Plus, Tubliseal EWT, Pulp Canal Sealer EWT, and Sealapex produced mild cytotoxicity.