一种求解地下结构顶板频率和振型的方法

采用欧拉梁横向自由振动理论,发展了一种求解浅埋地下结构顶板频率和振型的方法.鉴于地下结构顶板频率求解问题的复杂性,首先将该问题假定为平面应变问题求解,推导出浅埋地下结构顶板梁的自由振动方程;然后根据顶板梁的边界条件,得到了顶板梁的频率方程,从而得出了顶板梁的频率和振型;进一步得出了墙体转动刚度对顶板频率影响的规律,即转...

A Method for Determining Frequencies and Modes of Roof Slab of Underground Structure

A method for determining frequencies and vibration modes of the roof slab of shallowly buried underground structure is developed on the basis of the theory of transverse free vibration of Euler beam on elastic foundation.In view of the complexity of the determination of frequencies for roof slab of underground structure,this problem is assumed to be a plane strain problem.The free vibration equation of the roof slab of shallowly buried underground structure is derived.Then by using the boundary conditions, the frequency equation of the roof slab is obtained.Furthermore,the frequencies and vibration modes of the roof slab is obtained.It is concluded that the rotational stiffness of the side walls has negligible effect on the lower frequencies,but has great impact on the higher frequencies;moreover,the variation in frequencies of roof slab of underground structure with burying depth has been studied by considering the variation in soil stiffness with burying depth and the variation in attached mass of soil with depth burying due to the effect of soil arch.The obtained results may be used as a reference for the underground structure seismic design.