基于多孔介质理论的径向非均质饱和土-圆形隧道衬砌稳态响应研究

Steady State Response of Radial Heterogeneous Saturated Soil-circular Tunnel Lining Based on Theory of Porous Medium

  • 摘要: 考虑土体液相、施工和地应力等对隧道周围土体的影响,将隧道周围土体看作非均质饱和土,假设固相剪切模量沿径向变化。采用多圈层模型,将隧道周围饱和土划分为未扰动区域饱和土和扰动区域饱和土,扰动区域饱和土又划分为多个薄层同心环。求解了未扰动区域饱和土和各圈层饱和土的稳态解,得到了扰动区域饱和土外边界与内边界处固相位移、液相径向位移和固相径向应力之间的传递矩阵。将圆形隧道衬砌视为弹性介质,利用弹性动力学理论,得到了圆形隧道衬砌的径向位移和径向应力。考虑问题的接触面处的连续性条件和边界条件,得到了径向非均质饱和土-圆形隧道衬砌稳态响应的解析解。数值算例表明:饱和土固相径向位移和径向应力随频率变化曲线存在较为明显的波峰和波谷,且在Rω/v=1.0附近存在一定的突变。影响区域剪切模量比和剪切模量沿径向的变化规律,对非均质饱和土-圆形隧道衬砌的稳态响应有较大的影响,非均质特性和液相对饱和土-圆形隧道衬砌系统动力特性的影响,不能被忽略.

     

    Abstract: Considering the influence of liquid phase of soil, construction and in-situ stress on the soil around the tunnel, the soil around the tunnel was regarded as heterogeneous saturated soil, and it was assumed that the solid shear modulus of solid phase changed along the radial direction. Using the multi circle model, the saturated soil around the tunnel was divided into the undisturbed saturated soil and disturbed saturated soil, and the disturbed saturated soil was divided into multiple thin concentric rings. The steady-state solutions of saturated soil in undisturbed area and each circle were solved, and the transfer matrix between radial displacement of solid phase and liquid-phase, radial stress of solid phase at the outer and inner boundaries of saturated soil in the disturbed region was obtained. Taking the circular tunnel lining as elastic medium, the radial displacement and radial stress of the circular tunnel lining were obtained by using the elastic dynamics theory. Considering the continuity condition and the boundary condition of the problem, the analytical solution of the steady-state response of radial heterogeneous saturated soil-circular tunnel lining was obtained. Numerical examples showed that there were obvious peaks and troughs in the curves of radial displacement and radial stress of saturated soil varying with frequency, and there was a certain mutation near when Rω/v=1.0. The ratio of shear modulus in the affected area and the variation law of shear modulus along the radial direction had a great influence on the steady-state response of heterogeneous saturated soil-circular tunnel lining system, and the influence of tunnel lining thickness had a certain relationship with frequency. The influence of heterogeneous characteristics and the liquid phase on the dynamic characteristics of saturated soil-circular tunnel lining system could not be ignored.

     

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