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为研究悬臂抗滑桩加固堆积型滑坡的地震响应、抗滑桩桩后动土压力和桩身弯矩分布规律,设计完成50倍重力加速度条件下的悬臂抗滑桩加固堆积型滑坡离心振动台模型试验。试验过程中,采用汶川地震清溪台站反演的基岩波作为基底输入,不断增大输入地震波的幅值,通过监测滑坡不同位置加速度响应、抗滑桩桩后动土压力和桩身应变研究不同强度地震动作用下悬臂抗滑桩加固堆积型滑坡的抗震性能。试验结果表明:滑坡土体中加速度响应随高程增加而增大,趋于坡顶时放大效果最大,具有明显的高程放大效应,而滑坡坡面处呈现浅表放大效应;抗滑桩加固使滑体土体响应受到一定限制;桩后动土压力随着地震动的输入迅速增大至峰值,此后保持稳定形成残余动土压力作用于抗滑桩上;抗滑桩各截面动弯矩呈现出凸形分布规律,弯矩最大值出现在基岩面附近处;桩后动土压力和桩身动弯矩均随着地震动强度的增大而增大。所得到的成果为边坡悬臂抗滑桩抗震设计提供良好的基础。
In order to study the seismic response of cantilever anti-slide piles and the distribution of post-anti-slide piles and bending moments of pile landslide, the centrifugal shaker model of pile-type landslide strengthened with cantilever anti-slide piles under 50 times of gravity acceleration test. During the test, the bedrock wave retrieved from Qingxi station of Wenchuan earthquake was used as the base input to continuously increase the amplitude of input seismic wave. The acceleration responses at different positions of landslide were monitored. Seismic behavior of pile - supported landslide strengthened by cantilever anti - slide piles under strength earthquake. The experimental results show that the acceleration response of landslide increases with the increase of elevation, and the amplification effect tends to the maximum when it approaches the top of slope, with obvious elevation amplification effect, while the shallow surface enlargement effect appears on the landslide slope. The response of soil body is limited to some extent; the earth pressure increases rapidly to the peak value with the input of ground motion, and then remains stable to form the residual earth pressure acting on the anti-slide pile; the dynamic bending moment of each section of anti-slide pile shows convex shape The law of distribution and the maximum of bending moment appear near the bedrock surface. The earth pressure and dynamic bending moment of pile increase with the increase of earthquake intensity. The obtained results provide a good foundation for the seismic design of cantilever anti-slide piles.