爆炸荷载作用下深埋圆形隧洞饱和土-衬砌系统的动力响应

考虑隧洞衬砌内壁对爆炸波的反射作用及其负压效应,将衬砌视为弹性介质,研究了深埋圆形隧洞饱和土-弹性衬砌耦合系统在隧洞轴线发生爆炸时的轴对称瞬态动力响应。首先,基于Biot理论和弹性理论,考虑边界条件以及弹性衬砌和饱和土接触面处的连续性条件,利用Laplace变换得到饱和土和弹性衬砌位移、应力和孔隙水压力等在Laplace变换域中的解析表达式。在此基础上,利用Laplace数值逆变换得到其时间域的动力响应,数值分析重点考察了不同隧洞模型和不同爆炸载荷模型对饱和土动力响应的影响,并进行了参数研究。结果表明:爆炸波反射产生的负压效应对饱和土体的动力响应有显著影响。同时,饱和土-壳体衬砌系统、饱和土-弹性衬砌系统和无衬砌饱和土隧洞的响应性态基本一致,但响应周期和幅度依次增大。

DYNAMICAL ANALYSIS OF A SATURATED SOIL-LINING SYSTEM WITH A DEEPLY BURIED CIRCULAR TUNNEL SUBJIECTED TO A BLAST LOAD

Considering the reflection and the effect of suction pressure of explosion wave on inner lining, and assuming the lining as the elastic medium, the axisymmetrical transient dynamic responses of a saturated soil-elastic lining coupled system with a deep tunnel, subjected to a blast loading, are investigated. First, based on the Biot theory and the elasticity, under the boundary conditions as well as the continuity conditions on the interface between the saturated soil and elastic lining, analytical expressions of the displacements and stresses of the saturated soil and elastic lining as well as the pore water pressure expression in the Laplace transformed domain are derived by means of the Laplace transform. Then the dynamical responses in the time domain of the saturated soil are obtained using the numerical inverse Laplace transform. The influences of the different tunnel models and different blast loading models on the dynamical responses of the saturated soil are numerically examined, and parameter studies are conducted. It is revealed that the effect of the suction pressure due to the explosion wave reflection on the dynamical responses of the saturated soil is significant. Furthermore, the response of the saturated soil-shell lining system, saturated soil-elastic lining system and saturated soil without lining are almost the same, but the periods and amplitudes of the responses are different.