The study of behavior of Japanese castles masonry walls during earthquake and their stability

日本城堡的砖墙是用独立的石块堆砌而成，不使用石灰，他们的技术非常独特，就像在角落的Sori-Curve或Sanngi法。因此，它们是非常重要的世界遗产。本文的研究结果如下：(1)在振动台上，制作了相似比为1/10的模型墙体。从振动试验中可以看出，墙体的角度对墙体的稳定性有影响，墙体的变形和加速度从底部到顶部都有所放大。(2)通过模型墙体肩部的加载试验，明确了上部荷载应位于堆石长度范围内。(3)有限元数值试验表明，墙体的变形和加速度从底部到顶部增大。结果表明，地震波的振幅增大，但地面内部的加速度减小。但在墙体内部，振幅和加速度分别被放大。因此，在地震作用下，墙顶有坍塌的危险。墙体的稳定性主要受墙体高度或角度的影响，材料的性质影响不大。

Japanese castle's masonry walls were piled up with the independent stone block without using lime, and their techniques are very unique like Sori-curve or Sanngi-method at corner. So they are very important world heritage. But because of aging, many of them are very dangerous to the collapse.The results of this study are as follows.(1) On the vibration table, we made the model masonry walls of similarity ratio=1/10. From the vibration tests, it was made clear that the stability of masonry walls were effected by the angle of walls, and the deformation and the acceleration are amplified from the base to the top.(2) From the loading test at the shoulder of walls using the model masonry walls, it was made clear that the upper load should be located within the length of piling stone.(3) From the numerical experiment using FEM, it was made clear that the earthquake wave's amplitude was amplified, but the acceleration was reduced within the ground. But respectively, the amplitude and the acceleration were amplified within the masonry walls. There-fore, the top of walls is dangerous to the collapse during earthquake. And the stability of walls is effected mainly by the height or the angle, and the property of matters are not so effective.