采用Hankel积分变换方法,研究了Gibson地基在内源简谐荷载作用下的动力响应问题:通过构造积分围道技术,利用对围道上奇点的特殊处理,以消除驻波相来满足实际波的辐射条件,得到了Gibson地基埋置点源简谐荷载的动力Green函数。通过具体算例,分析了地基土体非均质性、荷载埋置深度和激振频率等因素对地基土体表面竖向位移的影响。结果显示:(1)荷载埋置深度和荷载激振频率对地基表面位移幅值大小和波动性都影响较大;f2)低频荷载作用下,地基土体的非均质性对其表面位移有较大影响。
The problems of Gibson subgrade subjected to interior harmonic excitation were investigated by Hankel integral-transform method. Integral contour was structured, and singular points on the contour were disposed specially to meet the radiation condition of wave. Dynamic Green's function of Gibson subgrade subjected to interior harmonic excitation was thus obtained. By means of numerical quadrature, vertical surface displacement was evaluated and the influences of degree of non-homogeneity, excitation depth and excitation frequency in the subgrade were investigated. It was shown that: (1) depth and excitation frequency of load have large influence on the magnitude and the wave characteristic of vertical surface displacement; (2) degree of soil's non-homogeneity has large influence on vertical surface displacement when subjected to low-frequency interior excitation.