Evaluation of Slope Failure Possibility on Forest Road Using Fuzzy Theory(I) - On the Fill Slope of the Metamorphic Rock Area -

Fuzzy이론(理論)을 이용(利用)한 임도사면(林道斜面)의 붕괴가능성(崩壞可能性) 평가(評價)(I) - 변성암지역(變成岩地域)의 성토사면(盛土斜面)을 중심(中心)으로 -

This study was carried out to evaluate the fill slope failure possibility of forest road in Metamorphic rock area using fuzzy theory which is non-linear model. The results were summarized as follows. The potential slope failure by nine factors was mainly occurred under the such conditions as the total road width ranging from 4m to 5m, longitudinal gradients below $2^{\circ}$, fill slope length greater than 8m, fill slope gradients steeper than $40^{\circ}$, road on ridge position, soil types with weathered rock, slope gradients steeper than $40^{\circ}$, aspect of NW, and longitudinal slope form in convexity. The weight of importance by factors on fill slope failure was ranked in the order of fill slope length, fill slope gradient, road position, soil type, aspect and longitudinal slope form. The analysis showed that the fill slope failure possibility was low with less than 0.485 of the fuzzy integral value and high with more than 0.620 of the value. And the discriminant accuracy was 74.6%. The analysis with six out of nine factors indicated that the possibility was low with less than 0.441 of the fuzzy integral value and high with more than 0.583 of the value. In this case, the discriminant accuracy was slightly increased to 78.0%.

본 연구는 변성암지역의 임도를 대상으로 비선형모델인 퍼지이론을 이용하여 임도 성토사면 붕괴가능성을 평가하였다. 그 결과는 다음과 같다. 요인별 붕괴위험도는 총노폭이 4~5m, 종단물매 $2^{\circ}$ 이하, 성토사면길이 8m이상, 성토사면경사 $40^{\circ}$ 이상, 노선위치는 능선부, 토질은 풍화암, 산지경사 $40^{\circ}$ 이상, 사면방위는 북서사면, 사면종단변형은 철(凸)형사면에서 가장 크게 나타났으며, 붕괴요인의 중요도는 성토사면길이>성토사면경사>임도위치>토질>사면방위>사면종단면형 순으로 나타났다. 퍼지이론에 의한 임도 성토사면의 붕괴가능성은 퍼지적분값이 0.485이하에서 안정, 0.620이상은 붕괴가능성이 큰 것으로 평가되었으며, 판별적중률은 74.6%로 나타났다. 또한 요인의 수준을 6개로 축소하여 붕괴가능성을 평가한 결과, 퍼지적분값이 0.441이하는 안정, 0.583이상은 붕괴가능성이 큰 것으로 나타났고, 판별적중률은 78.0%로 다소 향상되었다.