점성토로 뒤채움된 중력식옹벽에서의 인장균열 및 수평토압 : 비배수 해석

정성교,김형수 한국지반공학회 1997 지반 : 한국지반공학회지 Vol.13 No.4

Coulomb's theory has been usually used in practice to obtain lateral earth pressure against retaining wall. Such theory is based in the assumption that the lateral pressure is a tai angular distribution, since the point of applying the lateral thrust cannot be obtained by using it. However, the results of laboratory and field tests showed that the lateral pressure was not a triangular but a nonlinear distribution. To overcome the drawback of the Coulomb's theory, the different theoretical approaches(Handy, 1985. Kingsley, 1989 : Kellogg, 1993, Chung et at,1993, 1996a) were performed for gravity wall backfilled by cohesionless soil. On the other hand, for retaining wall backfilled by ,cohesive soil, theoretical analyses were carried out only on the basis of the Rankine's or Coulomb's concepts, but the equations showed different results. Here was newly derived the equations of lateral pressures under undrained condition against gravity wall backfilled by cohesive soil. They were based on the Coulomb's wedge, adopted the arching concept. Some of the equations were derived by neglecting tension crack, while the others by considering it. Comparative results for applying different examples showed that the equation considering tension crack might be reasonable. 옹벽에 작용하는 토압을 구하기 위하여 Coulomb이론이 실무에 대부분 사용되고 있지만, 전수평토압의 작용위치를 구할 수 없으므로 토압분포를 삼각형 분포라고 가정하고 있다. 그러나, 수 많은 실내 및 현장실험을 통하여 토압분포가 그렇지 않다는 것으로 규명되었다. 이러한 문제를 극복하기 위한 이론적인 접근이 Handy(1985), Kingsley(1989), Kellogg(1993), 정성교(1993, 1996a) 등에 의하여 비 점성토로 뒤채움된 옹벽에 대하여 수행되었다. 점성토로 뒤채움된 옹벽에 대한 기존의 이론적 접근은 단지 Rankine또는 Coulomb 이론에 근거하여 주로 수행되었지만, 그 이론들은 제각기 다른 결과를 보여주었다. 여기서는 점성토로 뒤채움된 중력식옹벽에 작용하는 수평토압을 위한 이론적 접근이 비배수 조건하에서 수행되었다. 이 접근은 Coulomb의 가정에 바탕을 두고 아칭개념을도입하였으며, 인장균열을 무시한 경우와 고려한 경우에 대하여 각각 이론식이 유도되었다. 그리고, 몇가지 조건에 대한 비교결과에서 인장균열을 고려한 토압이론식의 적용이 합리적일 것으로 사료되었다.

전시-P-87 : 원료 투입량과 다이스의 L/D비가 목재펠릿의 품질에 미치는 영향

정성교,정성교,노승규,한규성 韓國木材工學會 2013 한국목재공학회 학술발표논문집 Vol.2013 No.-

낙동강 하구지역 부산점토의 퇴적환경에 따른 압축특성

정성교,장우영 東亞大學校 工科大學 한국자원개발연구소 2007 硏究報告 Vol.31 No.1

안정사면에 인접한 옹벽에 작용하는 수평토압

정성교,정진교,이만렬,Jeong, Seong-Gyo,Jeong, Jin-Gyo,Lee, Man-Ryeol 한국지반공학회 1997 지반 : 한국지반공학회지 Vol.13 No.5

Classical earth pressure theories normally assume that ground condition remains uniform for considerable distance from the wall, and that the movement of the wall is enough to result in the development of an active pressure distribution. In the case of many low gravity walls in cut, constructed, for example, by using gabions or cribs, this is not commonly the case. In strong ground a steep temporary face will be excavated for reasons of economy, and a thin wedge of backfill will be placed behind the wall following its construetion. A designer then has the difficulty of selecting appropriate soil parameters and a reasonable method of calculating the earth pressure on the w리1. This paper starts by reviewing the existing solutions applicable to such geometry. A new silo and a wedge methods are developed for static and dynamic cases, and the results obtained from these are compared with two experimental results which more correctly mod el the geometry and strength of the wall, the fill, and the soil condition. Conclusions are drawn concerning both the magnitute and distribution of earth pressures to be supported by such walls.

쇼트피닝 가공한 기어강의 피로 특성에 관한 연구 ( A Study on the Fatigue Characteristics of Gear Steel by Shot Peening )

정성교,서유원,신용숭,정성균,이승호 대한기계학회 1999 대한기계학회 춘추학술대회 Vol.- No.-

EVRC의 고속 구현 알고리듬

정성교,최용수,김남건,윤대희 한국음향학회 2001 韓國音響學會誌 Vol.20 No.1

EVRC (Enhanced Variable Rate Codec)는 북미 및 우리 나라 CDMA 디지털 셀룰러 시스템에 채택되었으며 8kbps의 전송률에서 우수한 성능을 갖는 부호화기이다. 본 논문에서는 복잡한 알고리듬으로 인해 많은 계산량을 갖는 EVRC 부호화기를 성능 저하 없이 고속으로 구현할 수 있는 알고리듬을 제시한다. 제안된 고속 알고리듬에서는 효율적인 피치 검색과 고정 코드북 탐색 과정이 구현되는데, 고정 코드북 탐색 과정에서는 펄스 위치 조합의 수를 제한하는 방법과 줄여진 임펄스 응답을 사용하여 연산량을 기존의 방법의 70% 정도로 감소시킨다. 주관적인 음질 평가를 통해 제안된 고속 EVRC 알고리듬이 기존의 방법에 비해 적은 계산량에 구현되지만 음질의 저하는 초래하지 않는다는 것을 확인하였다. EVRC (Enhanced Variable Rate Codec) has been adopted as a standard coder for the CDMA digital cellular system in North America and Korea, and known to provide good call quality at 8kbps. In this paper, fast implementation algorithms for EVRC encoder are proposed. The proposed algorithms are based on both efficient pitch detection scheme and fast fixed codebook search algorithm. In the codebook search, computational complexity is reduced down to 70% of the original EVRC by limiting the number of pulse position combination and by using a truncated impulse response. The proposed algorithms enable us to implement the EVRC with much smaller computational works. Also, informal subjective tests confirmed that the difference in the speech quality between the original EVRC and the proposed method was indistinguishable.

$K_o$-재하/제하에 의한 건조모래의 거동(II): 다주기 시험

정성교,정진교 한국지반공학회 1995 지반 : 한국지반공학회지 Vol.11 No.1

다주기 Ko-재하/제하 시에 수평응력의 변화특성을 관찰하기 위하여 7종류의 시험모형을 선 정하였고, Ko조건을 크게 만족할 수 있도록 특별히 고안한압밀링 형태의 Ko-시험기를 제작하여 실내 건조된 모래에 대하여 실험을 수행하였다. 시험모형은 동일한 재하/제하 응력의 반복, 최대선행응력을 초과하는 반복 재하/제하, 그리고 최대선행 연직응력 내의 반복 재하/제하 Ko시험으로 구분된다. 실험결과에서 다주기 이력모형도 역시 기존의 단주기 이력모형을 확대하여 사용할 수 있음을 보였다. 여기서, 제하시의 지수 (a 및 a*)와 재재하 시의 계수(mr 및 mr*)는 응력이력의 형태, 반복회수 및 상대밀도에 따라 주로 지배되었다. In order to investigate the characteristics of the lateral earth pressure at rest under hysteretic Ko -loading l unloading conditions. Seven types of multicyclic models have been studied experimentally using dry sand. For this study a new type of Ko -oedometer appal attn is developed, and horizontal pressure is accurately measured. The multi cyclic models consist of largely 3 cases : (i) Ko-test under the same loading/unloading condition, (ii) multi-cyclic loading /unloading Ko -test exceeding the maximum prevertical stress, and (iii) multi-cyclic loading l unloading Ko -test within the mazimium prevertical stress. As a result, the multi -cyclic model showed that single-cyclic model could be extended as well, in which the exponents for unloading condition(a and a') and the reloading coefficients(m, and m*) were mainily dependent upon type of stress model, number of cycles and relati ve density.

연직배수재가 부분관입된 대심도 연약지반에 대한 압밀해석

정성교,제호경,진현식 東亞大學校 建設技術硏究所 1999 硏究論文集 Vol.23 No.1

The flat area in the estuary of Nakdong river is broadly covered with soft clay deposit of 20 to 60 meters in thickness. For the ground improvement, most of vertical drains used are partially penetrated up to about 25 meters in depth, because the soft ground is very thick. And then, the untreated zone exists at this reclamation site. However, it is very difficult for such a case to predict successfully the settlement and its elapsed time. In this paper, a finite element analysis was performed to investigate the consolidation behaviour for the case. The analysed result was compared with those of different consolidation theories and the observational procedures. As the compared result, because of the effects of stage construction and various ground conditions at different depths, the consolidation theories lead to the underestimated for predicting its consolidation rate. And the sooner is the time analyzed by the observational procedures, the smaller is predicted the final consolidation settlement.

케이슨 튜브 가물막이의 시공안정성 검토

정성교,김성렬,N. T. Dung,김민석 東亞大學校 建設技術硏究所 2005 硏究論文集 Vol.29 No.1

휴리스틱을 이용한 2차원 임의형상 부재 배치 문제

정성교,전건욱 대한산업공학회 2008 산업공학 Vol.21 No.1

A new search procedure, VLT(Vertex Line Tracing) heuristic, for two dimensional irregular shapes nesting problem was suggested in this study. The VLT heuristic was suggested to the nesting problem to overcome disadvantages of the existing NFP(No-Fit-Polygon) method. This VLT heuristic was compared with the results of the existing benchmark problems suggested by Albano, Hopper, and Burke. The results of the VLT heuristic give efficient solutions in the point of the scrap ratio and computation time. A computer program, NestLogic, using C++ for VLT heuristic was also developed for this nesting problem.