预应力格构梁基底反力分布规律模型试验研究

MODEL TEST STUDY ON CONTACT PRESSURE OF PRESTRESSED ANCHOR LATTICE BEAM

针对现有格构梁内力计算方法中对梁底反力研究的不足,通过1：2比例尺的大型物理模型试验,分析研究了预应力格构梁基底反力的分布规律.分析结果表明格构梁基底反力分布不均匀,横梁基底反力为结点大、跨中小;竖梁基底反力为上部小、下部大,呈梯形分布,且随着坡顶加载量的增加,这种趋势越加明显;预应力阶段各横梁基底反力相等,滑坡发展阶段各横梁基底反力呈上小下大梯形分布;竖梁各跨土压力均值与对应横梁均值存在一定比例关系,其比例系数范围为0.4～0.6;格构梁角结点基底反力最大,边结点次之,中结点最小,比例关系为2.15：1.15：1.00.

This paper examines the deficiency in research about the contact pressure of current lattice beam internal force calculation methods. It carries out the study of a 1: 2 large-scale physical model test and analyzes the distribution of foundation counterforce. The result indicates that the distribution of beam contact pressure is not uniform. For horizontal beam,the foundation counterforce near node is stronger than that in the middle segment of the beam. For vertical beam,the reaction appears to be a trapezoidal distribution with top weaker and this trend is more obvious with the loading. The contact pressure of each horizontal beam is equal in prestressing stage while it appears a distribution as the vertical beam in landslide developing stage. There is a certain proportion relationship between the span reaction of vertical beams and that of the corresponding horizontal beam span. The coefficient of proportionality is between 0. 4 and 0. 6. The reaction force is all different among the angle node,the edge node and the center node. It is the strongest at the angle node. The edge node comes the second. The center node weakest.Their proportions are 2. 15︰1. 15︰1. 00.