Junya YAMAMOTO
Research on the Behavior of a Falling Rock Protection System with Buffer Devices by Static Analysis
Eiji IWASAKI
Rock fall disaster occurs frequently in Japan. Therefore, a great number of falling rocks countermeasure projects are carried along the country. One of the rock fall protection systems is the rock fall protection net with buffer devices which in addition of having a great absorbing capacity of rock fall energy its construction and maintenance are simple. However, during the design stage of this kind of system the development of a performance evaluation test which takes a lot of time and cost is required.
With respect to this problem, the performance evaluation test results were simulated by a dynamic response analysis, but still this analysis requires much effort. Therefore, in this research a simplification of the dynamic response analysis, with the intention of reducing time design, was performed.
The maximum deflection amount as well as the maximum sliding amount are key parameters required for the design of a falling rock protection system. With the intention for reducing design time, these parameters were calculated by a static analysis. In order to validate the accuracy of the method, the obtained results were compared with those obtained in the dynamic response analysis. Then, the validation of the method was carried out by developing some static analysis models of the rock fall protection net considering different weight collision points and modifying the scale of the net. The effect of these conditions on the results of the static analysis was determined.
The results obtained are described as follows:
¡¦In order to convert the dynamic response analysis into a static analysis an energetically equivalent formula was proposed.
¡¦It was determined that the maximum deflection amount as well as the maximum sliding amount can be accurately replicated by using a static analysis. As a result, a significant reduction of the design time becomes possible.
¡¦Important findings on the effect caused by varying the rock fall protection net size as well as the weight collision point were concluded.
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