铁路桩基础桥台抗震性能参数影响分析

为了揭示桩基础桥台在地震作用下抗震性能的变化规律,以铁路重力式桥台为研究对象,通过数值模拟的方式分析桩头轴压比、桩基配筋率和桥台高度3种因素对桥台滞回曲线、骨架曲线、耗能能力的影响。研究结果表明:桥台正方向(远离填土)和负方向(面向填土)滞回曲线呈明显非对称分布,这与桩基础、混凝土柱等结构的轴对称分布有较大差异;在相同加载位移的情况下,增大桩基配筋率和桩头轴压比可以提高结构的承载力但会降低耗能能力;同等条件下,桥台负方向的刚度是正方向的7倍,承载力是正方向的10倍;桥台负方向由于加载过程中的脱空、隆起现象耗能能力会有所降低。因此需要考虑桥台的特殊性,防止出现远离填土一侧过早破坏引起的经济损失和安全隐患。

Analysis of the influence of seismic performance parameters of railway abutment with pile foundation

In order to reveal the change law of seismic behavior of abutment with pile foundation under earthquake action,taking railway gravity abutment as the research object,and the influences of pile head axial compression ratio,pile reinforcement ratio and abutment height on hysteretic curve,skeleton curve and energy dissipation capacity of abutment were analyzed by numerical simulation.The results show that the hysteretic curves of the abutment in positive direction(away from the filling)and negative direction(towards the filling)exhibit obvious asymmetrical distribution,which is quite different from the axisymmetric distribution of pile foundation and concrete column and other structures.Under the same condition of loading displacement,the increase of the reinforcement ratio and pile head axial compression ratio can improve the bearing capacity of the structure but will decrease the energy dissipation capacity.The stiffness of the abutment in negative direction is 7 times that of positive direction,and the bearing capacity is 10 times that of the positive direction under the same condition.The energy dissipation capacity of abutment in negative direction is reduced due to the abutment disengaging and uplift during loading.Therefore,the particularity of abutment needs to be considered to prevent the economic loss and potential safety hazard caused by premature failure far away from the side of the filling soil.