杜运兴 袁兰 周芬

摘   要：采用缩尺模型试验及三维有限元模拟研究了预应力筋长度对加筋体水平土压力分布的影响及加筋体中预应力筋的预拉力作用机理. 研究表明：墙背土压力的大小与分布规律与预应力筋长度无关;预拉力作用下，预应力筋位置填料的水平土压力沿筋长方向呈两端大中间小的分布规律，其中部填料的水平土压力值增幅随预应力筋长度的增大而减小;随着预拉力的增加，填料水平应力值会超过竖向应力值并与大主应力值完全重合;填料的平均破坏比系数呈先减小后增大的变化趋势，填料的应力水平表明在预拉力作用下填料存在最优的应力状态.

关键词：加筋土挡墙;预拉力;土压力;机理分析;模型试验;有限元分析

中图分类号：TU472.3                            文献标志码：A

文章编号：1674—2974（2019）09—0100—08

Abstract： The influence of the length of prestressed reinforcement on the distribution of horizontal earth pressure and the prestress mechanism of prestressed reinforcement were studied by using scale model test and three-dimensional finite element simulation. The study showed that the value and distribution of the earth pressure on the panel were independent on the length of prestressed reinforcement. With the action of prestress， the horizontal earth pressure value of prestressed reinforced layer was large at ends and small in the middle along the direction of reinforcement. The increase range of the pressure at middle of the layer decreased with the increase of the length of the prestressed reinforcement. With the increase of prestress， the horizontal stress value of filler can exceed the vertical stress value and coincide with the large principal stress value completely. The average failure ratio coefficient of filler decreased with the increase of prestress， and the stress level of filler presented an optimal safety state for the filler under the action of prestress.

Key words： reinforced earth retaining wall;prestressed;earth pressure;mechanism analysis;model test;finite element method

加筋土結构因具有造价经济、对地基承载力要求低、对地基变形适应性强等优点被广泛应用于铁路、公路、水利等工程领域[1-2]. 随着加筋土技术的广泛应用和深入研究，新型的加筋材料及加筋土形式应运而生. 无黏结预应力加筋土技术就是近年来被提出的一种新型加筋技术. 该技术由预应力筋、墙面板、侧压板及填料构成. 其中预应力筋两端分别与墙面板、侧压板连接，填筑完成后可以对预应力筋进行张拉，使墙面板、侧压板之间的填料产生水平约束，从而达到增强填料强度、减小填料变形的目的. 加筋体内水平土压力的大小与分布规律能……