刚性墙面双面加筋土挡墙动力响应振动台模型试验研究

Shaking table test of the back-to-back reinforced soil walls with full-height rigid facing

设计并完成了1:4的刚性墙面双面加筋土挡墙振动台试验,在满足相似关系的前提下,通过输入不同幅值的水平向正弦波,分析刚性墙面双面加筋土挡墙的动力响应特性。研究结果表明:两侧加筋区和中部非加筋区的加速度沿着高度方向均呈现出明显的放大效应,并在挡墙顶部达到最大值。随着加载幅值的增加,双面加筋土挡墙顶部的最大放大系数主要分为3个阶段,分别是平稳段、上升段与衰减段。最大墙面位移和残余位移沿着高度方向呈线性增大。当加载幅值未超过临界加速度时,位移量较小;而加载幅值超过临界加速度时,位移会迅速增大。同时,临界加速度对双面加筋土挡墙的变形模式有着决定性作用。刚性墙面双面加筋土挡墙的筋材动应变增量随着加载幅值持续施加而不断增大。底层的最大筋材应变增量出现在连接处,且沿着高度方向,最大筋材应变增量的位置不断向内部移动。

An experimental study was conducted on shaking table tests of 1/4-scale back-to-back reinforced soil walls with full-height rigid facing.The reduced-scale model was designed according to the similitude relationships and excited using a series of sinusoidal input motions with increasing acceleration,to investigate the dynamic response of back-to-back reinforced soil walls with full-height rigid facing.The results indicate that the acceleration amplification factors on reinforced soil zone and retained soil zone increase significantly with increasing elevation and reach the maximum at the top of the wall.The maximum acceleration amplification factors under input motions with increasing acceleration amplitude can be divided into three stages,including stable stage,rising stage,and attenuation stage.The incremental maximum dynamic and residual facing displacements increase in a linear manner with elevation.For the input motion smaller than the critical acceleration,facing displacements are smaller,while facing displacements increase rapidly for the input motion exceeding the critical acceleration.In addition,the critical acceleration has an important influence on the deformation modes for back-to-back reinforced soil walls with full-height rigid facing.The incremental reinforcement tensile strains increase significantly with increasing input acceleration,and the incremental maximum strain in each reinforcement layer generally occurred near the connection in the lower layers and moved further inward along the height direction in the upper layers.