Geo-structures such as levee and cut slope contain uncertainty in soil properties. Therefore, a probabilistic analysis considering the uncertainty of soil properties is required. In this study, probabilistic safety assessment of levee and cut slope has been performed.

The cut slope distributed in domestic, which have single horizontal extension over 200m and 50m of vertical height are classified into 2nd class facility by <Special Act On The Safety Management Of Structures>. Collapse of these cut slope occurs by thaw, rainfall, soil characteristics. Recently, frequency of small size cut slope collapse is increasing. Accordingly, central government partially revised <Special Act On The Safety Management Of Structures> with the contents of expansion of 2nd class facility's scope and standard and it is expected to be an effective maintenance and management measures of cut slope. Therefore, this study analyzed distribution type and characteristics of the national highway cut slope within the scope of relevant laws and regulations based on the status data of 2nd class facility (cut slope) to examine the maintenance status.

In general, protection and reinforcement measures on cut slope are often focused natural slopes to slope design are considered as slopes of safety. In this study, stability analysis is carried out and the differences to the factor were safety based on cases of analyzed erosion and surface collapse on boundary between Cut slope and Upper natural slope.

Surface of slope have occurred necessarily in regard to constructing road in South Korea which consist of 70% of mountain. Recently, large cut slope's formation increase because of increasing construction of the wide width road. therefore, the importance of maintenance have risen because the bigger scale of slope, the higher risk of collapse and damage increase. Korea Government have designated the large scaled cut slope to manage the slope which have the length of over 200 meters and the height of over 50 meters in accordance with 「Special law regarding facility safety management」. In this study, of the total number of 146's large scaled cut slope which is located at general national road in south korea, the slope dropped safety grade according to time flow was classified as joint, crushing and weak rock slope. moreover, weakness factors which influence the falling down safety grade were analyzed defending on the kind of rocks.

Vegetation surveys were performed at 45 plots along 10 highways cut slopes in South Korea. Total floral inventory, species richness and exotic plant percentage were obtained within each plot. Life history and life form of each species appeared were analyzed. Community types were classified using hierarchical cluster analysis and detrended correspondence analysis and non-metric multidimensional scaling were conducted from vegetation matrix. 292 species of vascular plants were discovered and the number of natives and exotics were 226 and 66, respectively. There were no significant differences of species richness and exotic plant percentage between cut slopes and rest areas. Hierarchical cluster analysis indicated five clear vegetation associations in cut slopes and rest areas. Detrended correspondence analysis indicated that species composition of total and native plants were similar along the highway cut slopes whereas exotic plants were distributed differentially along the highway cut slopes. In non-metric multidimensional scaling, the studied sites were more separated from each other on the basis of their species composition than the results of detrended correspondence analysis with respect to total, native and exotic plants. The both ordination represented that exotic plants have not been made uniform yet on cut slopes and rest areas by highway corridor in spite of diverse chronosequences after highway construction termination (1 to 22 years). This study showed that the distribution of species composition in exotic plants was different and localized on cut slopes and rest areas of highway in this representative peninsula area of North East Asia and the invasion of exotic plants can retard the process of plant species homogenization.

사면거동 및 파괴를 분석하기 위하여, 일반적으로 암반사면에는 Polynomial model, 토사사면에는 Growth model을 별도로 적용하여 사용하여 왔다. 이 기법은 사면의 파괴예측보다 사면의 누적변위를 묘사하기 위한 그래프 형태 위주이다. 따라서 본 연구에서는 사면의 거동보다는 파괴 예측에 초점을 맞추어 일반적으로 사용되는 두 모델을 병합하여 파괴예측을 위한 Asymptote(점근선)과 누적변위량도 같이 묘사할 수 있는 3차 방정식 모델 (3-degree polynomial model)로 단일화 할 것을 제안하여 현장 계측 data를 분석하였다. 국도 절취 사면부인 단양군 고수재 사면과 영덕군 축산면에 위치한 영덕 사면에 본 해석 모델을 적용하였다. 고수재는 토사사면으로 Growth model에 다른 거동을 나타내었고, 영덕사면은 Polynomial model에 따른 거동을 나타내었다. 분석결과, Polynomial model 과 Growth model로 구분된 해석 모델 형태를 의 형태를 가지는 3차 방정식을 사용하면, 하나의 모델로 사면의 거동 및 파괴를 해석할 수 있으며, 그 거동 해석 및 파괴 예측능력이 더 우수하다는 것이 증명되었다. Polynomial model의 경우, 방정식의 차수를 증가시켜도, 그래프의 값과 형태가 유사함을 알 수 있었다.