水电站地下厂房结构地震反应显式有限元分析

Explicit Finite Element Analysis of Underground Powerhouse Structure of Hydropower Stations for Seismic Responses

为充分利用围岩的支撑作用,减小结构变形和振动,地下厂房结构通常会采用锚杆将上下游侧立柱与围岩紧密连接,但此种处理措施对地下厂房地震反应的影响尚不明确。为了解立柱与围岩连接方式对地下厂房地震反应的影响,通过使用显式动力有限元分析软件LS-DYNA,基于粘弹性边界理论和等效地震荷载输入方法,计算分析了水电站地下厂房结构的地震反应。计算结果表明,与采用锚杆将上下游立柱与围岩紧密连接时相比,立柱与围岩分离时,立柱及与立柱相连的楼板和风罩等上部结构在水平地震下的位移反应有所减小,动拉应力值明显下降,特别是上下游侧立柱的内力会大幅降低。由此可见,将上下游侧立柱与岩体分离对减小地下厂房结构的地震反应更为有利。

To make full use of the surrounding rocks and reduce deformation and vibration of the structure ,anchors are commonly used for connecting upstream and downstream side columns with surrounding rocks .But the influences of this measure on the seismic response of the underground powerhouse remains unclear .To research the effects of connection type between surrounding rock and columns along the upstream and the downstream sides on the seismic response of un-derground powerhouse ,the seismic response of underground powerhouse is analyzed by the explicit dynamic finite element analysis software LS -DYNA based on viscous-spring boundary theory and equivalent seismic load input method .The re-sults indicate that ,comparing with anchoring the upstream and downstream side columns on the surrounding rocks ,keep-ing separation between columns and rock can reduce the displacement response and the dynamic tensile stress of the upper structures such as floor slabs and wind cover .Especially the internal force of the upstream and downstream side columns will be greatly reduced when separating them from the surrounding rocks .So ,it can be concluded that ,separating the upstream and downstream side columns from the surrounding rocks is beneficial in reducing the seismic response of under-ground powerhouse structure .