砖石古塔模型振动台试验的离散元模拟分析

砖石古塔块体间黏结强度较低，受地震作用易产生裂缝后发生破坏，为研究砖石古塔在地震作用下开裂及裂缝发展机制，以玄奘塔1/8缩尺模型结构为对象，建立离散元模型，计算了地震波激励下结构的加速度及位移反应，与振动台试验结果进行对比，分析了塔体开裂破坏全过程。结果表明，数值计算所得结构的加速度及位移反应与振动台试验结果一致，当地震烈度较低时，两者顶层位移变化曲线基本一致；烈度提高后，塔体开裂导致结构动力响应的计算值与试验结果出现差异，但两者的变化规律相同。在地震波激励下，塔体首层先开裂，随地震烈度的提高延伸至中部塔层，块体第2层出现阶梯状错动，模型损伤过程与试验裂缝发展状况基本吻合。研究结果为砖石古塔地震损伤及破坏过程分析提供了参考。

Discrete element simulation analysis of shaking table test of masonry ancient pagoda model

Historical masonry pagodas have low bonding strength,which is easy to crack and destroy under earthquake action.How to study the cracking and fracture development mechanism of masonry pagodas under earthquake excitation,a discrete element model was established for the 1/8 scale model structure of the pagoda of Xuanzang,and the acceleration and displacement responses of the structure under seismic wave excitation was analyzed.Compared with the shaking table test results,the whole tower cracking and destruction.The results show that the acceleration and displacement responses of the structure obtained by numerical calculation are consistent with the shaking table test results.When the earthquake intensity is low,the displacement curves of the top floor from the numerical analysis and the experiment are close.After the earthquake intensity increases,the numerical results of the structural dynamic response caused by the tower cracking differ from the test results.Still,the trends of both are the same.Under the excitation of seismic waves,the tower''s first floor cracked first,and with the increase of seismic intensity,cracking extended to the middle tower floor,and the block staggered on the second floor.The damage process of the model is consistent with the development of experimental cracks.The research results provide a reference for the analysis of earthquake damage and the failure process of masonry pagodas.