In order to protect Chinese ancient walls,the city walls under the Corner Palace in the Forbidden City is taken as an example to study effects to their mechanical characteristics after considering additional relics in the superstructure.ANSYS program is used for analysis.Based on mechanical parameters of wall bricks and soils,a finite element model for the corner walls is built.Two load cases are considered:before and after considering additional loads.By contact analysis deformation as well as inner forces of the walls and soil for the two cases are obtained.Results show that after increase of additional relics in the superstructure,peak values of deformation and compression stress for the walls increase little;but for tensile stress as it exceeds the permissible value,the walls may be destroyed for tensile strength failure.Thus additional relics are not advised to be stored in the superstructure for the safey of corner walls.%为保护古城墙,以故宫角楼位置的城墙为例,研究了角楼内增设文物对城墙的受力性能影响.利用ANSYS仿真技术,根据城墙砌体及城土的力学参数,建立了角楼处城墙有限元模型,进行了接触分析.通过分别考虑角楼内增设文物前后两种工况,研究了城墙的内力和变形,获得了不同条件下角楼处城墙的承载能力.结果表明:角楼内增设文物前后,城墙的变形及压应力变化不大,且在容许值范围内;但城墙的主拉应力峰值在增设文物后超过容许值.因此,从保护文物角度上讲,现有角楼处城墙承载性能已达到正常使用极限状态,不适宜存放增设文物.
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