黄土地层锁脚锚管横向地基反力系数

以马兰组黄土地层锁脚锚管为例，开展了锁脚锚管的模拟加载试验，反算了锁脚锚管横向地基反力系数的比例系数，研究了横向地基反力系数的比例系数随锁脚锚管端部竖向荷载和位移的变化规律，分析了锁脚锚管打设角度对横向地基反力系数的影响；拟合了横向地基反力系数的比例系数随锁脚锚管端部竖向位移变化的回归方程，确定了横向地基反力系数的比例系数的上下限，通过插值计算了0°~30°范围内任意角度打设的锁脚锚管的横向地基反力系数的比例系数。分析结果表明:在加载初期，随着锁脚锚管端部竖向荷载和位移的增大，锁脚锚管周围黄土处于不断压密阶段，横向地基反力系数的比例系数迅速增大；当锁脚锚管周围黄土进入渐进破坏阶段后，横向地基反力系数的比例系数随锁脚锚管端部竖向荷载和位移的增大不断减小；相对于0°打设的锁脚锚管，以30°打设的锁脚锚管的横向地基反力系数的比例系数随锁脚锚管端部竖向荷载和位移的变化幅值明显减小；在进行马兰组黄土地层隧道锁脚锚管设计计算中，直径为51 mm的锁脚锚管采用0°~30°打设时，横向地基反力系数的比例系数的取值范围为66.9~296·1 MN·m-4；单根直径51 mm的锁脚锚管能承受的竖向荷载为8.63~11.87 kN。 

Lateral foundation reaction coefficient of feet-lock pipe in loess stratum

A simulated loading test of a feet-lock pipe in the Malan loess stratum was conducted. The proportional coefficient of lateral foundation reaction coefficient of the feet-lock pipe was obtained through the inverse calculation. The variations in the proportional coefficient of lateral foundation reaction coefficient with the vertical load and displacement at the end of the feet-lock pipe were studied. The influence of installation angle of feet-lock pipe on the lateral foundation reaction coefficient was analyzed. The regression equation of the proportional coefficient of lateral foundation reaction coefficient with respect to the vertical displacement at the end of feet-lock pipe was fitted. The upper and lower limits of the proportional coefficient of lateral foundation reaction coefficient were determined. The proportional coefficients of lateral foundation reaction coefficient of feet-lock pipe with arbitrary angles in the range of 0°-30° were acquired through the interpolation calculation. Research results show that the proportional coefficient of lateral foundation reaction coefficient increases rapidly as the vertical load and displacement at the end of feet-lock pipe increase in the early stage of loading. This occurs because the loess around the feet-lock pipe is compacted continuously. When the loess around the feet-lock pipe enters the progressive failure stage, the proportional coefficient of lateral foundation reaction coefficient decreases continuously as the vertical load and displacement at the end of feet-lock pipe increase. The proportional coefficient of lateral foundation reaction coefficient of a feet-lock pipe installed at an angle of 30° exhibits significantly smaller variations with the vertical load and displacement compared with that of a feet-lock pipe installed at an angle of 0°. In the design and calculation of feet-lock pipe of tunnels in Malan loess stratum, when a feet-lock pipe with a diameter of 51 mm is installed at an angle between 0° and 30°, the proportional coefficient of lateral foundation reaction coefficient ranges from 66.9 to 296.1 MN·m-4. The vertical load that a single feet-lock pipe with a diameter of 51 mm can bear is between 8.63 and 11.87 kN. 2 tabs, 13 figs, 31 refs.