ABSTRACT

Seismic vulnerability of speleothems may serve long-term seismic risk studies. For this reason, the seismic response of stalagmite is computed using a robust FEM model calibrated from free vibration records by Hilbert–Huang modal extraction. It is demonstrated that the stalagmite vibrations consist of pairs of closely coupled flexural natural modes with a negligible role of vertical excitations. The location of the breaking point of the stalagmite is a result of a balance between the overturning bending moment and variations of horizontal cross-sections with height. Safety margins are investigated, and the ultimate peak velocity of excitations equaling 3.4 mm/s is estimated.

摘要

洞穴的地震脆弱性可用于长期地震风险研究。出于这个原因，石笋的地震响应是使用稳健的 FEM 模型计算的，该模型是通过 Hilbert-Huang 模态提取从自由振动记录中校准的。结果表明，石笋振动由成对的紧密耦合的弯曲自然模式组成，垂直激励的作用可以忽略不计。石笋断裂点的位置是倾覆弯矩与水平横截面随高度变化之间平衡的结果。研究了安全裕度，并估计了等于 3.4 mm/s 的激发的最终峰值速度。