地震荷载作用下大坝非线性响应的混沌分析

从能量角度出发,推导出大坝-地基结构系统在地震荷载作用下响应的拉格朗日动力方程,在此基础上建立了该系统的非线性动力学模型,并运用混沌理论方法,对系统的非线性动力学行为进行了时域、相空间、庞加莱映射、Liapunov指数等内容的混沌分析和讨论。结果表明:地基土层的密度、厚度等土层性质的变化都会对坝体的非线性响应表现出复杂的非线性混沌关系,其通向混沌之路是通过倍周期分叉实现的。

Chaotic analysis of nonlinear response of dams under earthquake

The Lagrange dynamic equation of dam-foundation structure system under seismic load was derived from system energy.The nonlinear dynamic model of the system was established by using the chaotic theory,and the chaotic behavior of nonlinear dynamics the system response due to earthquake was discussed and analyzed in the time domain,in the phase space,by the Poincaré map,and with the Liapunov exponent and so on.It was shown that the variation of parameters of foundation soil property,such as the soil density,thickness and so on,would be chaotically related with the response of dam due to the seismic load.