预应力锚索加固石窟围岩的地震响应的数值模拟分析研究

针对预应力锚索加固石窟文物的特点,阐述了影响石窟围岩变形稳定性的主要因素和动力有限元分析方法。以榆林窟的三个典型工程剖面为实例,通过对不同峰值加速度、频谱、持续时间的动荷载作用下预应力锚索加固的石窟围岩位移场、应力场分布特征的数值模拟计算,揭示了预应力锚索加固石窟岩体在地震作用下的动态响应和变化规律。分析结果表明,随着地震动峰值加速度(PGA)、反应谱特征周期和地震动持续时间的增大,洞窟的位移和应力值明显增大,应力集中区的范围扩大,围岩损伤的可能性增加,稳定性降低。应力分布与洞窟数量、组合特性、几何形状和尺寸密切相关,并控制了石窟围岩的震害特征。本文为石窟文物的科学保护和岩体抗震加固与减灾提供了理论基础和实践依据。

Numerical Simulation of Seismic Response of Rocks Surrounding Grottoes Reinforced by Prestressed Anchor Cables

Considering the characteristics of the rocks surrounding Grotto Relics reinforced by prestressed anchor cables,the influence factors and dynamic finite element analysis methods are described.Focusing on three sections of Yulin Grottoes in Axin of Gansu Province,the dynamic response of rock mass is revealed through numerical simulation of displacement and stress field under dynamic loads with different PGA,spectra and durations.The results indicate weak points for seismic retrofitting.It also shows that the displacement and stress increase,range of stress concentration expands and the damages probability of country rock increases with the increasing of peak ground acceleration(PGA),characteristic period and duration of dynamic loads.The distribution of stresses is closely related to the quantity,combined feature,geometry shape and size of caves.This paper provides theoretical basis and practical reference for the preservation of grotto relics and seismic retrofit and seismic hazard mitigation for the rock mass.