地铁荷载下隧道周围粉性土变形的22因子设计
22 Factorial Design for Deformation of Silty Soilaround Tunnel under Subway Loading

为研究地铁荷载作用下饱和粉性土的累积塑性变形特性，针对上海地铁10号线国权路附近的饱和粉性土进行多功能GDS循环三轴试验，考虑振动频率、动应力幅值对累积塑性应变的影响。试验结果表明：相同振动频率下，动应力幅值越大产生的累积塑性应变就越大；相同动应力幅值条件下，频率越小产生的累积塑性应变就越大。采用22因子设计法进行分析，得到振动频率、动应力幅值及振动频率与动应力幅值互作等因素均对累积塑性应变有显著影响。通过回归分析理论，建立考虑振动频率、动应力幅值及振动频率与动应力幅值互作等因素的累积塑性应变的非线性方程，并对方程进行检验。该研究成果能为控制地铁运营产生的沉降提供有价值的理论依据。
To study the cumulative plastic deformation characteristics of saturated silty soil under subway loads, the GDS cyclic triaxial testing system was used to test the saturated silty soil near the Guoquan Road, Shanghai Metro Line 10. The effects of vibration frequency and dynamic stress amplitude on the cumulative plastic strain were considered. The experimental results show that the cumulative plastic strain increases with the dynamic stress amplitude, and with the same dynamic stress amplitude, the cumulative plastic strain increases as the frequency decreases. By an analysis with the 22 factorial design method, it was found that the vibration frequency, the dynamic stress amplitude, and the interaction between the two have a significant effect on the cumulative plastic strain. Based on the theory of regression analysis, the nonlinear equation of cumulative plastic strain was established, which considers the vibration frequency, the dynamic stress amplitude, and the interaction between the two, and the equation was tested. The research results can provide a valuable theoretical basis for controlling the subsidence induced by subway operation.