耐風特性を考慮した斜面上緑化樹木の安定性に関する研究

在大面积开发中，需要绿化树代替早期恢复自然环境。但在本工程中，风害对坡上支架的影响并不明显。本研究的目的是分析由根、茎、枝、冠组成的树木抗风结构的总体机理，构建基于根茎断裂模型的绿化树木设计方法。本分析所需的基本数据是树根的强度、林分的杨氏模量、林分和树枝的振动特性。3年的研究结果总结如下：首先，从树桩阻力矩过程出发，考虑了对林分下点施加拉力拔根试验的结果。在此力作用下，建立了根拔的阻力矩模型。在不获取树桩根系的情况下，建立了简化模型。其次，对8种阔叶树和针叶树进行了根系拉伸试验。破裂载荷随破裂部分直径的次幂而变化。根的强度与茎的木质部一致。第三，整理了历次拔除试验结果。结果表明，最大拔根阻力矩与林分胸径的3次方成正比。第四，测定林分杨氏模量，柳杉的杨氏模量约为80tf/m^2，青杉的杨氏模量约为100tf/m^2。测量了大风对树木的影响。主振动周期为0.66Hz，与风压周期相同。

The revegitation tree is required in place of to early restore the natural environment in the development of large area. But the influence of wind damage does not make clear for the stand on slope in this project. The object of this study analysis the total mechanism of sturcture with wind resistance for tree which consists of roots, stem, branches, and crown, and construct the method used in design of revegetation tree based on the model of uprooting and stem breakage. Fundamental data required this analysis is strength of roots, Young's modulus of stands, characteristics of vibration of stands and branches.The results for 3 years studying summarize as following. First, Results of uprooting test by applying tensile force to lower point of stands were considered from the process of the resistance moment for tree stump. And the model of resistance moment was constructed for uprooting in the case of this force acting to stand. Furthermore, simplified model was made in case of no obtaining the root system of tree stump. Second, the tensile test of roots was made for 8 species of hardwood and conifer. The rupture load varied as the second power of the diameter in the part of rupture. And root strength was as the xylem of stem. Third, The results of past uprooting test were arranded. And it was made clear that the maximum resistance moment of uprooting was proporting to the third power of the breast diameter of stand. Forth, Young's modulus of stand was measured, the value of cryptomeria japonica was about 80tf/m^2, and the value of chamecyparis obtusa was about 100tf/m^2. The variation of tree by high wind was measured. The main period of vibration was 0.66Hz as same as periods of wind pressure in this case.