地下结构中柱在竖向地震作用下动力响应研究

Dynamic Response of Mid-pillar under Vertical Seismic Load in Underground Structure

使用了结构动力学有关理论,研究了当竖向地震发生时双层双跨地下结构上下两层中柱的动力响应。为了解决问题的简便,首先可以将地下结构作为刚体来研究,利用土—地下结构之间的相互作用获得刚体在竖向地震作用下的动力响应。然后,利用地下结构的对称性,取一半地下结构来进行研究计算,侧墙与底板、顶板的约束使用抗弯弹簧替换。之后,利用边界条件可以把刚体动力响应输入顶板和底板中,以便获得底板和顶板的剪力,最后得到上下两层中柱的受力情况。结果表明,竖向地震作用对双层地下结构上下两层中柱的作用是比较明显的,并有可能对地下结构中柱产生严重的破坏,同时下层中柱相比于上层中柱的竖向作用更加明显。

A structural dynamics method is used to study the dynamic response of mid-pillar under vertical seismic load in double-story and double-span shallowly buried underground structure. Firstly,the underground structure was treated as rigid body and the dynamic response of structure under vertical seismic load was obtained by analyzing the interaction between rigid body and foundation. Second,due to the symmetry of the underground structure,half of the structure is taken into consideration. The bending restraint of side wall was replaced by a bending spring. Shear forces of bottom slab and roof slab was obtained by inputting the dynamic response previously achieved. Finally,the stress of mid-pillar was obtained. The results show that the effect of vertical seismic excitation is significant for the 2 mid-pillars,which even cause serious damage. Compare lower mid-pillar with upper midpillar,the vertical effect is more significant for the lower mid-pillar.