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

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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.