A Study on Numerical Evaluation of Sliding and Accumulating Behavior of Roof Snow

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12650583
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Building structures/materials
• Research Institution: Hachinohe Institute of Technology
• Principal Investigator: TAKITA Mitsugu Hachinohe Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (60171584)
• Co-Investigator(Kenkyū-buntansha): WATANABE Masatomo Hachinohe Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (70005362)
• Project Period (FY): 2000 – 2001
• Keywords: roof snow disposin / sliding ＆ accumulating / physical experiment / non-snow material / rice husks / numerical analysis / Distinct Element Method / Object-Oriented Technology

Research Abstract

The objective of this study is to develop a technique to evaluate the stack of roof snow on the ground. The technique is one of essentials to design housings that dispose roof snow by sliding. The studies on roof snow disposing have been done by physical experiment or field work. The authors aim to establish a technique to evaluate roof snow behavior on sliding on roof and accumulating on the ground by co-operating physical experiment and numerical analysis.
In 2000, the study was done on the following items : (1) development of a numerical analysis system based on the Distinct Element Method by the Object-Oriented techniques, (2) evaluation of roof snow behavior, for the case of granular snow, by physical experiment on non-snow material. By the study on the behaviors of snow particles in collision, compression and contacting, the analysis system was improved. By the experiment on non-snow material, the effects of the material properties, namely density, grading and angle of repose were clarified and it was confirmed that the rice husks are appropriate.
In 2001 the study was done on the following items : (1) analyzing of principal factors on the roof snow behavior, based on the results of physical experiment, (2) the improvement of the analysis system based on the previous result, (3) the development of simple method to evaluate roof snow behavior. By the comparison between the result of the physical experiment and the numerical results by the analysis modeled snow as rigid body blocks, the following results was obtained : (a) the result by rice husks gives similar result as the rigid body analysis (b) the position of the top of accumulation by the rigid body analysis gives good agreement with the physical experiment when the maximum static friction constant is applied, c the width of accumulation by the physical experiment becomes two times of the width by the rigid body analysis. By the study on the analysis system, the analysis on the basic property on the system and the simulation of the physical experiment, the followings are clarified : (d) the relationship between the parameters on the snow particles, damping factor, tensile property and so on, and the behavior of the snow was clarified, (e) it will be important to evaluate the risk on the special distribution of roof snow during sliding down, (f) it will be required to improve the analysis system to make higher the contacting force between snow particles.