Development of fencing system with less snow damage in snowy areas

为减少雪区带刺铁丝围栏的雪害，进行了围栏系统的研究。得到的结果如下：1。围栏系统需要在放牧期间具有防止牛从围栏中逃脱的功能，并且具有在雪地中不受雪荷载作用的结构条件，这是其他关于牧场设施的研究中发现的。牛在围栏外吃草时，牛推铁丝网的负荷估计在200公斤以上。我们必须用高强钢丝设计围栏的高强钢丝张力。雪区坡地牧场和放牧林设置了倒刺铁丝和高强度铁丝围栏。建造费用分别为每米637 ~ 685日元和123 ~ 414日元。维修费用分别为每米13.9 ~ 37.5日元和1.3 ~ 7.1日元。从这些结果来看，高强度铁丝围栏作为一种围栏系统，在围栏的建造和维护方面比铁丝网围栏保持更低的成本，减少了积雪的破坏。在对围网结构变化的调查中，围网柱尖沉和钢丝松动现象逐年增多。高强度钢丝围栏的钢丝张力至少降低了30%，有必要在围栏中设计稳定的角柱。4个带刺铁丝网围栏的放牧距离为12.7 cm， 3个高拉丝围栏（顶部通电110 cm）的放牧距离为13.8 cm，一个80 cm高拉丝围栏的放牧距离为9.1 cm。结果表明，电围栏比铁丝网更能防止牛在围栏外吃草。在雪域坡地，在没有足够的围栏维护的情况下，新型围栏系统与有刺铁丝围栏的功能存在明显差异。

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.