锚杆格构支护边坡振动台模型试验研究

 以锚杆格构支护的均值土坡为研究对象，设计并完成了几何相似常数为15的硅胶边坡模型振动台试验，研究了支护结构的动力地震响应特征。通过试验，得出如下结论：(1) 在同一正弦波激励下，格构同一测点的动应变值的变化范围是基本保持不变的，与正弦波激励的变化规律一致。但在破坏阶段，测点的动应变值表现为无规律的变化且应变值均较大。(2) 同一激励下，横、纵格构梁的受力水平是基本相平的；对于同一行格构，中间应变值较大；同一列格构，由上到下呈“大→小→大→小”的变化特征，说明边坡竖向变形变化很大且受锚杆约束的影响；格构梁的不同部位受力不同，需要对薄弱部位进行补强。(3) 相同频率下，格构测点的动应变值随着加速度的增大，整体上表现为递增趋势。(4) 低频正弦波的频率较接近边坡的自振频率，坡体加速的动力响应就明显，边坡的相对位移则越大，因此，格构的动应变相应增大。试验结果表明，试验采用的硅胶边坡模型可用于边坡支护结构的动力响应分析，且模型可以重复使用，极大地降低了试验成本。

EXPERIMENTAL STUDY OF SLOPES SUPPORTED WITH FRAMED ANCHORS ON SHAKING TABLE

To study the dynamic response of homogeneous slopes supported by lattice beams under earthquake，a small slopes model made of silica gel on shaking table was designed at the geometric scale of 1∶15. Under the same sinusoidal loading，the range of the strains at the same measuring point on the lattice beam is found to be largely unchanged before the failure and the strains varied sinusoidal accordingly. But in the stage of failure，the dynamic strains vary irregularly and reach very large values finally in the destruction phase. Additionally，the stress level of the horizontal lattice beam is the same as that of the vertical lattice beam under the same seismic excitations. For the horizontal lattice beams，the strains at the middle of the beams are larger than those at two ends of the beams. And for the vertical beams，the strains from the top to the bottom exhibit a feature of larger- smaller-larger-smaller variation，indicating that the slope deformation along the vertical beams are restrained by the anchors. When the frequency of the sinusoidal loading is the same，the dynamic strains on the lattice beams increase with the increasing of the seismic acceleration. When the input acceleration is the same，the measured strains are larger at low frequency cases than those at high frequency ones. The reason is that the input low frequency is close to the natural frequency of the model and thus the dynamic responses in low frequency conditions are stronger. The results demonstrate that the silicone slope model is suitable for studying the dynamic response of the slope with supporting structure. The model can be used repeatedly and greatly reduces the cost of test.