为研究抗滑桩和锚杆联合支护下边坡的地震响应规律及破坏过程,开展了相应的振动台模型试验。通过输入三种不同地震波,不断增大地震波的峰值,得到了支挡结构的动应力分布规律及加固机理。试验表明:①坡体裂缝的产生对其加速度响应规律影响很大,在裂缝产生后,常规的响应规律将发生突变。②在高烈度地震波作用下,深层次的基岩也会受到一定程度的损伤破坏,深层的破坏可能使得对边坡失稳模式的常规设防(针对滑动面)变得失去意义。③在地震过程中,由于坡体向外滑动,同一锚杆的不同位置发挥最大抗力的时间具有先后顺序,靠近坡面的锚杆段首先达到最大值,依次为后面的自由段、锚固段。④在地震作用较小时,桩后动土压力近似成抛物线分布,桩前动土压力成矩形分布;随着地震作用的增大,靠近滑带处的桩前、桩后动土压力增长较快。试验结果为该支挡形式的抗震设计提供有益的参考。
In practice, to make a study on the seismic response and dynamic effects of anti-slide piles and anchor bars, shaking table test was applied. Seismic performance and dynamic stresses distribution of the retaining structure were investigated by, constantly increasing the peak values of input three different earthquake waves. The experimental results indicate that: (1) Crack makes a great influence on slope dynamic response: when there are cracks, the traditional dynamic response of the slope would change significantly. (2) When high intensity seismic wave is applied, bedrock would get damaged, which leads to the conventional seismic fortification useless. (3) Earthquake would lead to slope sliding, the time for reaching maxium resisting force in different locations of the same anchor bar is not the same, the section near slope surface first, followed by free-field section and anchorage zone. (4) When the input seismic load is low, the distribution of dynamic stress is parabola for soil after pile and rectangle before pile; when the input seismic load gets greater, the dynamic stress near smooth zone grows fast. The test results provide valuable references for aseismic design of this retaining form in slope engineering.