爆炸作用下拱形结构反射系数计算方法研究

STUDY OF REFLECTIVE COEFFICEIENTS OF UNDERGROUND PROTECHIVE ARCHES UNDER BLAST LOADS

为了计算爆炸荷载作用下地下拱形结构上的动荷载,引入了Costantino荷载模型考虑拱结构拱曲率对介质-结构相互作用机理的影响,在单自由度体系位移模式的基础上利用虚功原理,求解爆炸荷载作用下拱形结构的反射系数,即作用到结构上的均布动荷载峰值与结构板块处自由场应力的均布峰值之比。讨论了拱曲率、结构刚度、介质参数对反射系数的影响。在此基础上,与规范中平顶结构的综合反射系数计算方法进行了比较,引入修正系数对公式进行修正,改进后的反射系数计算方法对于不同的结构形式具有更广泛的适用性。

To explore the blast loading acted on the underground protective arches, the Costantino model （MM） is introduced to consider the structure-medium interaction （SMI）, in which the radius effect to the dynamic interaction is included. The displacement mode of the arch is assumed based on the equivalent single degree of freedom method, and the dynamic interaction equation of the structure is set up by the virtual work principle. The reflective coefficients are calculated by the ratio of the average peak stress of the dynamic loads to that of the free stresses. Influences of arch radius, structure stiffness, and medium modulus are discussed. Traditional reflective coefficient method is then modified by introducing new parameters to extend its applications to much more structure styles.