中文摘要：

根据Biot理论及Euler-Bernoulli理论,建立饱和土体地基上的无限长梁受简谐移动荷载作用模型;由梁-土体系的变形协调条件,推导梁-土体系的等效刚度;由Fourier变换得到时间-空间域的梁-土体动力响应;分析荷载速度、频率、饱和土体的参数对梁-土体系的影响。研究结果表明：当荷载在某一低频时,随着荷载速度增大,梁的最大竖向变形、弯矩也增大,而当移动荷载的频率较高时,荷载速度对梁的变形及内力的影响较小;对于饱和土体地基上的无限长梁,当荷载速度超过土体剪切波速时,梁仍然存在一系列其他模态所对应的关键速度,此时,梁有最大变形出现。

英文摘要：

According to Biot＇s theory and Euler-Bernoulli theory,the model of the infinite beam resting on a saturated poroelastic soil subjected to harmonic moving loads was put forward. The equivalent stiffness of the saturated poroelastic soil was obtained via the compatibility condition between the beam and the half space. The time domain solutions for the beam and the saturated poroelastic soil were derived by means of the inverse Fourier transform method. The influences of the load speed,frequency and material parameters of the poroelastic half space on the responses of the beam were investigated. In order to demonstrate the proposed method,some time-space domain examples and corresponding analysis were presented. The results show that the frequency corresponding to the maximum deflection and bending moment increases with the increase of load speed. Moreover,at higher frequencies,the dynamic response is independent of the load speed. For a beam overlying a saturated poroelastic half space,there still exist critical velocities corresponding to other modal orders even when the load velocity is larger than the shear wave speed of the medium.