组合支护结构加固高边坡的地震动响应特性研究

 基于原型边坡设计大型振动台模型试验，通过监测不同幅值和类型地震波作用时的桩身土压力、坡体加速度、格构梁位移和锚索预应力，研究组合结构与加固边坡体的动力响应特性，评价加固效果。试验结果表明：锚索与抗滑桩在地震时协同工作，桩身土压力随输入波幅值增加而增大，锚索预应力变化规律与边坡体的稳定程度有关，表现为先减小后增大；地震造成抗滑桩主动土压力的合力作用点上移至l/2处，被动土压力区的2个转点也发生明显变化；输入地震波峰值不大于0.5 g时，格构梁位移响应值较小，坡体中部抗滑桩以下不存在加速度放大效应，边坡整体稳定性好。另外，运用加速度时程的Hilbert边际谱研究了坡体内部的震害损伤特性，损伤识别结果与试验监测数据吻合。该研究成果可为更加合理地考虑地震区锚索格构梁–抗滑桩联合防护边坡的设计提供指导。

Shaking table test on seismic response of slopes reinforced by pile-cable retaining structure

The seismic behaviors of the slope reinforced with the multi-frame beam，anchor cables and double-row anti-slide piles were investigated with the large-scale shaking table model test. The earth pressure acting on the pile，the axis force in the anchor cable，the acceleration in the slope and the deformation of the frame-beam were measured under the action of El Centro and Wenchuan-Qingping earthquake waves. The anchors and anti-slide piles perform as a collaborative structure under earthquake. The earth pressure increases with the amplitude of input seismic waves. However，The variation of anchor cable prestress is related to the stability of the slope，its value decreases firstly and then increases. The acting point of the resultant force of the active earth pressure moves up to the position of l/2. The pivots of pile embedded bedrock are varied significantly. When the peak ground acceleration of input seismic wave is less than 0.5 g，the displacement response of the frame-beam is small and the acceleration amplification effect does not exist obviously below the pile in the middle part of slope. The damage characteristics of internal slope analyzed using the Hilbert marginal spectrum theory are in agreement with the measured data.