爆炸荷载作用下饱和半空间中衬砌隧道弹性动力响应IBIEM模拟

基于Biot两相介质理论，采用一种高精度间接边界积分方程法（IBIEM）研究了饱和半空间中浅埋衬砌隧道在内部爆炸荷载作用下的瞬态弹性动力反应。通过典型算例，给出了爆炸荷载作用下隧道附近地表位移、衬砌动应力、围岩径向位移和衬砌表面孔隙水压的时程响应，并对比分析了饱和半空间和全空间中隧道动力响应的区别。研究表明：覆土层厚度对浅埋隧道-围岩整体动力响应特征具有明显影响；衬砌表面透水状态对爆炸荷载的时程响应的影响不显著；随半空间饱和介质孔隙率增加，围岩受隧道内部爆炸影响程度降低，衬砌承担的爆炸作用增大；当和直达波、衬砌内部反射波的峰值叠加作用时，半空间表面反射波对衬砌隧道拱顶附近响应影响显著，使得衬砌动应力幅值、径向位移相比深埋情况大幅度增加。

DYNAMIC RESPONSE OF TUNNEL LINING UNDER ENDOGENOUS FUNCTION IN SATURATED POROELASTIC HALF-SPACE

Based on Biot’s theory of two-phase medium, a high-precision indirect boundary integral equation method is utilized to solve the transient dynamic response of elastic tunnel embedded in a saturated poroelastic half space under internal blast loading. Response time history about the ground displacement, tunnel hoop stress, radial displacement and pore pressure of surrounding rock under blast load are given by calculating, and analyzed the difference of time history response between the saturated half space and the whole space. The results show that the embedded depth has large effect on dynamic response of the shallow buried tunnel-surrounding rock system; the boundary drainage condition has little impact on the time history response under blast load. With the increase of porosity, the influence of blast load on surrounding saturated rock is reduced while the blast effects on the tunnel is increased. When the direct waves and reflected waves by tunnel surfaces are strengthened by the reflected waves from the half-space surface, the tunnel vault is obviously affected by the surface reflection wave and the amplitude of hoop stress and radial displacement of surrounding rock are much larger than the tunnel in a whole space.