地震荷载下桩-锚组合结构加固边坡的位移解析

Displacement Analysis of Slope Reinforced by Pile-Anchor Composite Structure under Seismic Loads

加固结构所的抗滑力常被简化为恒定值,不能反映其随时间的变化.为了更准确评估地震下桩-锚组合结构加固边坡的稳定性,引入非线性的模型,实现了抗滑力的实时更新.推导了安全系数和位移计算公式,讨论了结构系数对评估结果的影响.结果表明:(1)引入指数非线性模型后,抗滑桩和锚索力均表现出明显的时间效应.屈服加速度随结构的变形而增大.(2)地震初期抗滑桩无加固作用.随着边坡滑动,抗滑桩的力快速增长,最终起主导作用.(3)将结构的抗滑力等效为固定值虽然简化了计算,但是忽略了达到设计值所需的位移,这可能导致边坡的危险性被低估.在加固设计时,应该考虑抗滑力的变化.

The anti-sliding force provided by the reinforcement structure is often simplified to a constant value,which cannot reflect the change in the earthquake.To accurately evaluate the stability of the slope,the nonlinear mechanical model is introduced.Combined with the newmark method,the real-time update of the anti-sliding force is realized.The effect of vertical seismic loads on the slope is also considered.The calculation formulas of safety factor and displacement are deduced.Besides,the effect of structural coefficient changes on the results is discussed.The research shows follows:(1)After introducing the exponential nonlinear model,the anti-sliding forces show time effects and increase with earthquakes.(2)The anchor cable force at the initial stage of the earthquake is equal to the pre-tension force,and the stabilizing pile has no anti-sliding effect.As the slope slides,the force of the stabilizing pile grows rapidly and eventually dominates.(3)Equating the anti-sliding force of the structure as a fixed value simplifies the calculation,but the risk of slope instability is underestimated.In the reinforcement design,the deformation of the reinforcement structure should be considered.