急傾斜地における搬出施設について II : 3支点集材架線における費用計算

Abstract

3支点集材架線による搬出費用の計算をとおし集材機が具備すべき出力と使用索径の最適水準について検討した。搬出費用を集材機出力と使用索径の関数として表わし, その最小値を求めた。1m_2あたりの搬出費用の最大限を0. 5人工以下とし, 対象となる林地の大きさが等辺長200m以上の2等辺3角形とすれば, 集材機出力50馬力, 使用索径18 - 20mm (1. 2 - 1. 5kg/m) 前後が最適水準となる。その時の搬出費用を図11に示した。

In the present report we have studied the calculation of hauling cost and the most suitable condition between the power of yarder PS (HP) and the weight of wire rope ρ (kg/m) on the cable system with three supports. The hauling cost is considered to be a function of ρ and PS as equation (15) and (16). Equation (16) is considtred to be a function of length of side (r), angle (α), hauling volume (q), load (w), and cycle time according to equation (2), (3), (4), (5), and (12). A cycle time is calculated by equation (11) and (13) so that is affected significantly by average skidding distance as equation (13). Equation (17) may be used to determine the minimun hauling cost so the solutions are shown in Fig.4. Fig.6 and Fig.7 show relation between the hauling cost and the weight of wire rope at a constant power. These curves of hauling cost are not very much change between 0.9 and 1.8 kg/m and less than 0.5 man-day/m3. Fig.9 and Fig.10 show relation between the hauling cost and the power of yarder at a constant weight of wire rope. These curves are not very much change. Rearranging the calculation results, the most suitable condition of the powerof yarder is 50HP and weight of wire rope is 1.2-1.5kg/m. The results of the hauling cost are show in Fig.11.