侧向点爆炸作用下地下拱结构的动力响应

Dynamic response of underground arch structure under lateral point blast loads

首先,利用几何关系与介质中超压、位移衰减公式得出结构表面自由场荷载和位移的分布形式,并对衰减因数、爆距等参数进行讨论;其次,利用MSSI(modified soil-structure interaction)相互作用模型对拱的振动方程进行正交求解,得到任意角度荷载作用下的结构弹性动力响应解析解。基于动力响应解析解,得到了土体的声阻抗对结构位移、速度、加速度时程响应曲线的影响。研究结果表明:侧向爆炸荷载作用下,岩土介质声阻抗越大,埋设其中的地下结构的位移、速度和加速度变化越大。为此,建议地下防护结构应修建在声阻抗小的岩土介质中。

Firstly,the distribution of load and displacement of the free surface of the arch were obtained by using the geometrical relation and the empirical formula,and the related parameters were discussed.Secondly,the modified soil-structure interaction model was used to solve the vibration equation of the arch orthogonally,and get the analytic solution of the elastic dynamic response of the structure under arbitrary angle loading.Then the time histories curve of displacement,velocity and acceleration were predicted.The analysis results indicate that the responses of the arch are greatly influenced by the acoustic impedance.The larger the acoustic impedance,the greater the displacement,velocity and acceleration of the structure.So the protective structures are better to be constructed in a site with low acoustic impedance.