결정론적 기법을 이용한 산사태 위험지 예측

차경섭,장병욱,우철웅,김성필,Cha, Kyung-Seob,Chang, Pyoung-Wuck,Woo, Chull-Woong,Kim, Seong-Pil 한국농공학회 2005 한국농공학회논문집 Vol.47 No.6

Almost every year, Korea has been suffered from serious damages of lives and properties, due to landslides that are triggered by heavy rains in monsoon season. In this paper, we systematized the physically based landslide prediction model which consisted of 3 parts, infinite slope stability analysis model, groundwater flow model and soil depth model. To evaluate its applicability to the prediction of landslides, the data of actual landslides were plotted on the predicted areas on the GIS map. The matching rate of this model to the actual data was $84.8\%$. And the relation between hydrological and land form factors and potential landslide were analyzed.

지리정보시스템에 기반한 산지재해 예측

차경섭(Kyung Seob Cha),김태훈(Tae Hoon Kim),김영진(Young Jin Kim) 한국방재안전학회 2008 한국방재안전학회 논문집 Vol.1 No.4

우리나라에서는 해마다 여름철에 발생하는 태풍 및 집중호우에 기인한 산사태 및 절·성토지의 붕괴로 인한 피해가 계속되고 있다 본 연구에서는 지리정보시스템과 사면안정해석모형 분포형 지하수위모형 및 토심추정모형을 이용하여 산사태를 예측하는 기법을 개발하였다. 기법의 적용성을 검증하기 위하여 산사태가 많이 발생하였던 지역을 선정하고, 실제 산사태가 발생한 위치를 위성영상으로부터 파악하여 예측시스템에서 추정된 산사태 가능성과 비교·검증하였다 예측모델과 실제 데이터의 일치비율은 84.8%로 나타났다. 또한 수리학적, 지형적 요소와 산지재해의 관계도 분석되었다. Korea has been suffered from serious damages of lives and properties, due to landslides that are triggered by heavy rains in every monsoon season. This study developed the physically based landslide prediction model which consists of 3 parts, such as slope stability analysis model, groundwater flow model and soil depth model. To evaluate its applicability to the prediction of landslides, the data of actual landslides were plotted on the areas predicted on the GIS map. The matching rate of this model to the actual data was 84.8%. The relation between hydrological and landform factors and potential landslide were analyzed.

해상 가물막이 누수 보강사례연구

차경섭(Cha Kyung-Seob),김선주(Kim Sun-Ju),배경태(Bae Kyung-Tae),김태훈(Kim Young-Jin) 대한토목학회 2009 대한토목학회 학술대회 Vol.2009 No.10

선형보강재와 평면보강재를 적용한 토체의 전단강도 및 투수특성

차경섭 ( Cha Kyung Seob ),장병욱 ( Chang Pyoung Wuck ),우철웅 ( Woo Chull Woong ),박영곤 ( Park Young Kon ) 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.6

Traditional methods of earth reinforcement consist of introducing strips, fabrics, or grids into an earth mass. Recently, discrete fibers are simply added and mixed with the soil, much the same as cement, lime or other additives. The advantages of randomly distributed fibers is the maintenance of strength isotropy, low decrease in post-peak shear strength and high stability at failure. In this study, new composite reinforcement structures which consist of geotextile and randomly distributed discrete fibers were examined their engineering properties, such as shear strength of the composite reinforced soil and permeability of short fiber reinforced soil. The increments of shear strength of composite reinforced soils were the sum of increments by fiber and woven geotextile, respectively. The permeability of short fiber reinforced soil was increased with fiber mixing ratio.

단섬유 보강토의 투수 및 침식특성

차경섭 ( Cha Kyung Seob ),장병욱 ( Chang Pyoung Wuck ),김성필 ( Kim Sung Pil ),박재성 ( Park Jae Sung ),박영곤 ( Park Young Kon ) 한국농공학회 2003 한국농공학회 학술대회초록집 Vol.2003 No.-

A study for permeability and erosion characteristics of short fiber reinforced soils was performed. As mixing ratio increases from 0 to 1.0% permeability of short fiber reinforced soils increased but, maximum increment ratio(k_1.0%/k_0%) was 8.47. As a result of permeability test with 19, 38 and 60mm fiber reinforced soils, there were no difference in fiber length. Void ratio increased with increment of mixing ratio and decrease of compaction energy and as a result of plotting permeability and void ratio, log k increased linearly by void ratio. As a result of erosion test, soil erosion was decreased sharply by increase of fiber mixing ratio up to 1.0%. Despite increase of soil erosion by slope angle, the increment ratio was decreased by mixing ratio.

다중셀과 지형지수를 이용한 광역 산사태 위험지 예측

차경섭 ( Cha Kyung-seob ),장병욱 ( Chang Pyoung-wuck ) 한국농공학회 2004 한국농공학회 학술대회초록집 Vol.2004 No.-

본 연구에서는 여름철 집중호우시 많이 발생하는 산사태에 대한 예방대책 수립에 활용하기 위하여 사면안정모형과 수문모형을 지리정보시스템에 결합한 광역 산사태 위험지 예측 기법을 개발하였고, 경기도 장흥지역에서 발생한 산사태에 대하여 개발된 산사태 예측기법의 적용성을 검증하였다. 본 연구의 결과를 요약하면 다음과 같다. 1. 사면의 굴곡을 표현하기 위하여 셀과 셀을 결합한 다중셀을 정의하였다. 다중셀은 임의의 셀로부터 경사방향으로 2개 이상의 셀을 추출 · 결합한 형태로서 평탄, 볼록,오목, 복합사면의 형태를 갖는다. 2. 평탄사면과 굴곡이 있는 사면의 안전율을 비교하기 위하여 내부마찰각, 지하수위 등을 최소, 중간, 최대의 3가지 조건으로 변화시키고, 토심을 0.5m에서 2.0m까지 4가지, 점착력을 4가지, 경사도를 0.1 - 1.0(0° - 45°)까지 10단계로 변화시켜 총 43,200가지의 경우에 대하여 사면안전율을 계산하였다. 그 결과, 토질정수에 상관없이 굴곡이 커질수록 안전율이 선형적으로 감소하였는데, 이로부터 지형지수(LI)를 굴곡량에 대한 평탄사면에 대한 굴곡이 있는 사면의 안전율의 비로 정의하고 사면안정해석에 도입하였다. 지형지수는 아래와 같다. 3. 평균경사도 및 토심에 따른 지형지수를 산정하여 그래프로 도시한 결과 지형지수는 평균경사도의 함수로 표현이 되었고, 그 추세식은 아래와 같다. 다중셀의 사면각을 DEM으로부터 추출하여 평균경사도로부터 지형지수를 산정하고, 지형지수와 무한사면 안정해석결과로부터 굴곡이 있는 사면의 안전율을 산정할 수 있었다. 4. 구축된 예측시스템을 적용하여 산사태 발생지역과 안전율 1.1미만인 영역을 비교하여 본 결과, 무한사면안정해석에서는 실제 산사태가 발생된 영역과 84.8%가 중첩되고, 지들지수를 이용한 해석에서는 92.4%가 중첩되는 것으로 나타나 더 적합한 것으로 나타났다. The objective of this thesis is to develop a prediction system of potential landslide sites to apply to the prevention of landslide disaster which occurred during the heavy rainfall in the rainy season. The system was developed by combining a modified slope stability analysis model and a hydrological model. The modified slope stability analysis model, which was improved from 1-D infinite slope stability analysis model, has been taken into consideration of the flexion of the hill slopes. Multicell was introduced to describe the flexion of slopes (flat,convex, concave and complex slope). Landform index was introduced and defined as the safety factor ratio of flat slope and non-flat slope by flexion. The modified model was taken into account the flexion of hill slopes by combining the results from infinite slope stability analysis and landform index. Whereas it is too difficult to apply 2-D circular failure analysis model in GIS, this model can be easily applied to GIS because the model was developed on 1-D slope stability analysis. Jangheung in which lots of landslides were occurred between 1998 and 1999 was selected for the study area to verify the application of the system. And the actual landslide and the predicted areas were overlapped on the G/S map. The matching rate of this system was 92.4%. Besides the multicell analysis, the landslide susceptibility maps based on the extracted slopes and small watershed were made and verified their applications.

선형보강재와 평면보강재를 적용한 토체의 전단특성 연구

차경섭(Kyung-Seob Cha),장병욱(Pyoung-Wuck Chang),박영곤(Young-Kon Park) 한국토목섬유학회 2002 한국토목섬유학회 학술발표회 Vol.2002 No.11

해성점토의 압밀구성관계

차경섭 ( Cha Kyung Seob ),장병욱 ( Chang Pyoung Wuck ),원정윤 ( Won Jeong Yun ) 한국농공학회 2000 韓國農工學會誌 : 전원과 자원 Vol.42 No.3

Most soft ground in the southern and western coasts in Korea consists of very compressible alluvial deposits. Four samples in these alluvial deposits were selected to manifest the constitutive relations of consolidation. A series of tests were performed to investigate void ratio - effective stress relation and void ratio - coefficient of permeability relation on soil samples obtained at Haenam, Jindo, Mankyung, and Janghung. permeabilities by CRS thoery were similar to directly measured data. but those of indirectly computed by C_U shows difference. Several models about compressibility and permeability were compared with test data.

수분 재분포를 고려한 강우 침투 시 자연 사면에서의 포화깊이 산정

김웅구,장병욱,차경섭,Kim, Woong-Ku,Chang, Pyoung-Wuck,Cha, Kyung-Seob 한국농공학회 2006 한국농공학회논문집 Vol.48 No.1

In Korea, most landslides occurred during the rainy season and had a shallow failure plane parallel to the slope. For these types of rainfall-induced failures, the most important factor triggering slope unstability is decrease in the matric suction of unsaturated soils with increasing saturation depth by rainfall infiltration. The saturation depth was readily estimated using modified Green-Ampt model proposed by Chu et al. (Chu Model) at present. But Chu Model involves some problems for application, because water-redistribution phenomena were not effected. So the modified Chu Model (MCGAM) which reflect water redistribution phono mens was developed. The results showed that the MCGAM had a better agreement with measured volumetric water contents than existing Chu Model.

변형률속도에 따른 일정변형률시험의 압밀특성 비교연구

장병욱 ( Chang Pyoung Wuck ),차경섭 ( Cha Kyung Seob ),원정윤 ( Won Jeong Yun ) 한국농공학회 1998 한국농공학회 학술대회초록집 Vol.1998 No.-

This study performed to establish tile characteristics of constant rate of strain consolidation(CRSC) tests. The values obtained by the CRCS tests were compared with oedometer tests. From the comparision of the results of oedometer and CRSC tests for soft soil from Haenam, Korea, it was concluded that. 1. When rate of strain is 0.9mm/hr, compression curve of CRSC test was not coincided with those of tile oedometer test, then preconsolidation stress was larger than those of other rates of strain. 2. Permeabilities from CRSC tests and direct measurements were about same each other, but permeabilities from Oedometer tests were large than those from others.