爆炸荷载作用下饱和土中隧道的瞬态动力响应

用解析方法研究了爆炸荷载作用下饱和土中圆形隧道的动力响应问题。模型假定饱和土体中的圆形隧道中心处发生爆炸，爆炸荷载采用简化形式，衬砌运动方程基于Flügge壳体理论，饱和土采用Biot波动方程，通过引入两个势函数，在Laplace变换域中推导了爆炸荷载作用下圆形隧道位移和应力响应的表达式。利用Laplace数值逆变换得到爆炸荷载作用下衬砌与土体的时域计算结果，分析了排水条件对位移、应力变化的影响，并讨论了饱和土参数、衬砌和土的相对刚度的影响。数值结果表明，爆炸荷载作用下，不排水条件下应力和位移的响应幅值比排水条件下有所增大；饱和土参数
对土体应力的幅值有明显的影响；衬砌与土的相对刚度越大，土体位移和应力响应的幅值越小，衰减的速度也越快。

Transient dynamic response of tunnels subjected to blast loads in saturated soil

Using an analytical method, the dynamic response of a circular tunnel in the saturated soil is investigated. Assuming that the blast occurs in the center of the tunnel, a model is established using simplified blast loads. The motions of the liner are considered specially based on the Flügge theory. The Biot’s theory is used to describe the saturated soil. By introducing two potential functions, the analytical solutions of displacement and hoop stress induced by the blast loads are derived in Laplace transforms domain．Numerical results are obtained by inversion of Laplace transforms presented. The influences of permeable property of interface between the liner and soil on dynamic response of the tunnel are analyzed. Also, the influences of the parameters of the saturated soil and the relative rigidity of the liner are discussed. It is shown that the maximum stresses and displacements are both higher under impermeable conditions than those under permeable conditions. The parameter
has a significant effect on the amplitude of hoop stress. What’s more, the attenuation of the responses becomes more apparent as the rigidity of liner increases.