论文部分内容阅读
土工结构的震害调查表明,桩板墙具备优良的抗震性能,安装锚索之后效果更佳。尽管如此,目前关于桩板墙的研究大多数集中于静力方面,对于动力响应情况和抗震工作机制的研究较少,关于两类典型桩板墙,即桩板墙和锚索桩板墙的地震响应特性的对比研究未见报道。基于此,将桩板墙和锚索桩板墙进行了同台的大型振动台模型试验,对比分析了两种结构的地震响应特性。试验结果表明:两种结构的土压力、锚索拉力和桩身位移地震时程响应规律均与输入的地震动参数密切相关,如曲线形状和变化趋势,并且它们的峰值出现时刻与地震动加速度峰值出现时刻基本一致。锚索的安装,能更好地保持边坡的稳定性和有效限制桩身变形,尤其是在高地震烈度区,当土体非线性增强时,优势体现愈发明显,即预应力锚索会产生减小桩身位移的效果,特别是当地震系数为0.4时,普通桩板墙的位移达到预应力锚索桩板墙的2.4倍。此外,锚索拉力的施加,能够使桩对土体产生“主动”的反压力,两种结构在静力和地震系数为0.1的工况下桩背所受的滑坡推力基本一致,嵌固段土体抗力的差距也不明显,实测点强度的最大差异不超过20%,说明锚索的作用没有得到充分发挥;但当地震系数大于等于0.2后,锚索作用开始体现,桩土变形的协调性更好,桩背与滑体的相互作用力增大,土体抗力较桩板墙大幅度减小,更有利于边坡的稳定。同时,锚索拉力的作用使结构的悬臂段桩身内力较大,在进行结构设计时,相比于普通桩板墙,锚索桩板墙应加强悬臂段,可以适当弱化嵌固段。分析成果可供高烈度地震区桩板墙的抗震设计、灾后恢复重建及今后相关规范修订参考。
The earthquake damage investigation of geotechnical structures shows that the pile wall has excellent seismic performance and the effect is better after the anchor cable is installed. In spite of this, most of the current research on pile wall focuses on the static aspect, and there are few researches on the dynamic response and anti-seismic work mechanism. For the two types of typical pile wall, namely the pile wall and the anchor wall Seismic response characteristics of comparative studies have not been reported. Based on this, a large-scale shaking table model test was conducted on the pile wall and the anchor pile wall, and the seismic response characteristics of the two structures were compared and analyzed. The experimental results show that both the earth pressure, the tension of anchor cable and the response time of seismic response of pile displacement are closely related to the input ground motion parameters, such as the shape and trend of the curve, and their peak occurrence times and ground motion acceleration The peak appears basically the same time. The installation of the anchor cable can better maintain the stability of the slope and effectively limit the deformation of the pile, especially in the area with high seismic intensity. When the soil is non-linearly reinforced, the predominance manifests itself more and more. That is, the prestressed anchor cable Which has the effect of reducing the pile displacement. Especially when the seismic coefficient is 0.4, the displacement of common pile wall reaches 2.4 times of the prestressed anchor plate wall. In addition, the application of tension of the anchor cable can make the pile produce “active” backpressure to the soil. The thrust of the two structures is basically the same under the condition of static and seismic coefficient of 0.1, The difference of soil resistance in solid section is not obvious, and the maximum difference of measured point strength does not exceed 20%, which shows that the function of anchor cable is not fully exerted. However, when the earthquake coefficient is greater than or equal to 0.2, The coordination between the pile back and the sliding body increases, and the soil resistance greatly decreases compared with the pile wall, which is more conducive to the stability of the slope. At the same time, the pulling force of the anchor cable makes the internal force of the cantilever section of the structure larger. During the structural design, compared with the ordinary pile wall, the cantilever section should be strengthened and the embankment section should be properly weakened. The results of the analysis can be used for seismic design of post-earthquake wall, earthquake disaster recovery and reconstruction and reference for future revision of relevant codes.