Development of fencing system with less snow damage in snowy areas

为减少多雪地区带刺铁丝网的雪害，开展了一种围栏系统的研究。取得的结果如下：1.研究结果。根据对牧场设施的其他研究，围栏系统需要具有防止放牧期间牛群逃出围栏的功能，并具有在雪地中不受雪载作用的结构条件。在牛在栅栏外吃草时，牛推着的带刺铁丝网的负荷估计超过200 KGF。必须采用高张力钢丝设计护栏的高钢丝张力。在雪域的坡地牧场和放牧林中修建了带刺铁丝网和高强度铁丝网。它们的造价分别为每米637-685日圆和每米123-414日元。维修费用分别为13.9-37.5日元/米和1.3-7.1日元/米。从这些结果可以看出，高强度钢丝网作为一种减少积雪破坏的围栏系统，在建造和维护围栏方面都比带刺铁丝网保持了更低的成本。在调查护栏结构变化时，发现护栏柱尖端下沉、钢丝绳松动现象逐年增多。高强度钢丝网的钢丝张力至少降低了30%，因此有必要在栅栏中设计稳定的角柱。放牧距离：4根带刺铁丝网为12.7 cm，3根带电110 cm高强钢丝网为13.8 cm，1根80 cm高铁丝网为9.1 cm。与带刺铁丝网相比，电栅栏具有更好的防止牛群出栏的作用。新开发的栅栏系统与带刺铁丝网相比，在雪域缺乏护栏的坡地牧场上，栅栏功能有明显的差异。

Studies on a fencing system was carried out to reduce snow damage on the barbed wire fences in snowy areas. The results obtained are as follows.1. A fencing system needs to have a function to prevent the cattle escape from the fence in grazing period and to have structural conditions not to be acted by snow load in the snow, as finding out the other studies on pasture facilities. At the cattle grazing out of fence, the load of the barbed wire pushed by cattle was estimated over 200 kgf. We must design the high-wire tension of fence using high-tensile wire.2. Barbed wire fences and high-tensile wire fences were constructed in the sloping pastures and grazing forests in snowy area. Construction cost of them were 637-685 yen per meter and 123-414 yen per meter, respectively. Maintenance cost of them were 13.9-37.5 yen per meter and 1.3-7.1 yen per meter, respectively. From these results, high-tensile wire fences as a fencing system reduced snow damage were kept lower cost rather than barbed wire fences in both construction and maintenance of fences.3. As investigating the changes of fence structure, the tip and sank of fence post and the wire slackening were found more year by year. The wire tension of high-tensile wire fence were reduced by 30 % at least and it is necessary to design a stable corner post in the fence.4. Distance of grazing out of fence were 12.7 cm in 4 barbed-wire fence, 13.8 cm in 3 high tensile-wire fence with electrifying 110 cm top wire, and 9.1 cm in one electric-wire fence of 80 cm height. Electric fence was indicated a function of prevent the cattle from grazing out of fence than barbed wire fence.5. There were marked differences of fence function between a new fencing system developed and barbed wire fence in such as a sloping pasture without enough fence maintenance in snowy areas.