半空间内洞室在冲击荷载作用下的瞬态响应

为了研究外界冲击力对地下洞室及周围土体的影响, 对半空间弹性土体圆柱形洞室在突加反平面冲击荷载作用下的瞬态响应进行探讨.将列车急刹车时对隧道产生的冲击力简化为半无限弹性体中突加在圆柱形洞室表面沿轴线方向的均布荷载,利用残余变量法求得频域解,运用Durbin提出的拉普拉斯数值逆变换给出问题的数值解,并将计算结果与静力情况下的结果进行比较,分析土体应力和位移随时间、弹性波的传播距离以及夹角的变化,结果表明：波到达后,该点土体的应力和位移均瞬间增大,随后慢慢减小并逐渐趋于静力值,波向外发散传播,并沿半径方向衰减；对于相同的传播距离上的各点,最大动应力和动位移与夹角无关；应力和位移最后的稳定值随着夹角的增大而增大.

Transient response of cavity in half-space subjected to shock load

In order to investigate the impact of external impact force on the underground cavern and surrounding soil,the transient response to sudden anti-plane shock load of an elastic soil body half-space containing a cylindrical cavity was studied. The train impact load in tunnels was simplified to uniform sudden load along the axial direction applied on cylindrical cavity buried in the elastic soil half-space. The frequency domain solutions were obtained using residual variable method. And the Laplace numerical solutions of the problem were presented by the Laplace numerical inversion proposed by Durbin and compared with the static results. The variation of the stress and displacement with respect to the time, the propagation distance of elastic wave and the angle were presented. The results showed that: the stress and displacement of the receive point remain zero before the wave arrivals; until the shear wave strikes, the stress and displacement of that point increase abruptly, then reduce to the static value gradually; the soil displacement and stress responses attenuate along the radial direction; given a same radius, the maximum dynamic stress and displacement are almost independent of angle. However, the stable values grow up as angle increases.