微型桩-加筋土挡墙应力变形特性和加固机理分析

Study on stress and deformation behavior and reinforcement mechanism of Micropile- MSE Retaining Wall

为了增强公路加筋土挡墙系统的外部稳定性、护栏抗冲击性能,并控制加筋土的变形,提出了微型桩-加筋土挡墙系统:竖直和倾斜的一对微型桩从路面穿过加筋回填土区域,锚固进地基,同时在桩顶浇筑承台和地基梁,通过连接构件将公路护栏与地基梁及微型桩相连,形成一个自上而下的整体加固体系。利用数值手段对不同加筋土挡墙结构的应力变形特性和加固机理进行对比分析,结果表明:与"未加固"、"单根竖直桩加固"、"竖直桩+倾斜锚杆"以及"竖直桩+水平锚杆"这四种挡土墙工况相比,所提出的微型桩-加筋土挡墙的位移分别可以减小46.9%、34.6%、33.3%和22.7%,竖直桩身弯矩与后三者相比分别可以减小72.7%、72%和47.7%。因此,验证了微型桩-加筋土挡墙具有较好的应力变形特性。

In order to enhance the global stability and impact resistance of barrier of road MSE retaining wall, and also control the deformation of MSE, the Micropile - MSE Retaining Wall system is put forward ： a pair of vertical and inclined micropiles go through the MSE region and are anchored in the foundation, then pile cap and grade beam are placed on the pile top, after that, the road barrier is connected to the grade beam and micropiles by jointing elements, finally, a top - down reinforcement structure is formed integrally. Comparative stud- ies were done on the stress and deformation behavior as well as reinforcement mechanism of MSE retaining wall with different reinforcement methods through numerical method. The results turn out that compared with ＂unreinforced＂ , ＂single vertical pile reinforcement＂, ＂vertical pile plus inclined anchor＂ and ＂vertical pile plus horizontal anchor＂ MSE wall cases, the displacement of the proposed Micropile - MSE Retaining Wall can be reduced by 46.9%, 34.6%, 33.3% and 22.7%, respectively, and the bending moment of its vertical pile can be reduced by 72.7% , 72% and 47.7% compared to the last three cases, respectively, which indicates the effectiveness and superiority of Micropile - MSE Retaining Wall. As a result, it is proven that the Micropile - MSE Retaining Wall has favorable stress and deformation behavior.