Evaluation of Side-ditch Erosion Factors and Judgment of Side-ditch Stability in Forest Road

임도(林道) 옆도랑의 침식요인(浸蝕要因) 평가(評價)와 안정성(安定性) 판별(判別)에 관(關)한 연구(硏究)

This study was carried out to investigate the influence of the road structure and site conditions on side-ditch stability of forest road. For experimental purposes, the forest road in the Kwangrung Experimental Forest, Korea Forestry Research Institute, was chosen as a study site. A total of 556 plots wes set up as every longitudinal gradient changing points by belt-transect method. Data of 10 road structural characteristics and side-ditch stability were collected from each plot and analysed by Quantification II. The main factors in order of partial correlation coefficient were longitudinal gradient, road position, inclination of cut-slope, constituent material of cut-slopes, distance of surface flow, cross-sectional shape of road, pavement material, vegetation of cut-slopes and length of cut-slope. The erosion of side-ditch of forest road occurred in the following cases; more than 8% of the longitudinal gradient, road position of hill under side and foot hill, more than $50^{\circ}$ of inclination of cut-slope, constituent material of cut-slopes of hard soil and gravel soil, more than 80m of distance of surface flow, pavement material with earth or gravel, more than medium covered of vegetation of cut-slopes, and the straight and convex form of road-bed.

임도 옆도랑침식에 영향을 미치는 요인의 평가 및 안정도 판별을 위하여 광릉시험림의 임도를 대상으로 조사를 실시한 결과 침식에 미치는 기여순위는 종단물매, 시설위치, 절토사면경사, 절토사면구성물질, 유하거리, 노면형태, 노면재료, 절토사면피복도, 절토사면길이 순으로 나타났다. 임도 옆도랑침식을 유발하는 요인을 평가하면, 종단물매는 8% 이상, 임도시설위치는 산록(山麓)과 중복(中腹), 절토사면경사는 $50^{\circ}$ 이상, 절토사면토성은 견질토사, 자갈섞인 토사, 호박돌섞인 토사, 유하거리는 80m 이상의 지역에서, 그리고 노면재료는 토사도(土砂道)와 자갈부설도에서, 노면형태의 경우에는 철(凸)형과 직선형, 절토사면 피복도(被覆度)는 피복도가 중(中)이상인 곳에서 임도 옆도랑침식이 발생할 가능성이 높은 것으로 예측(豫測)되었다.