铁路预应力路堤加固技术数值研究

研究目的:铁路预应力路堤在国内外尚属一种新型路基加固法,其受力变形特性暂未得到系统化研究,相关加固设计理论仍处于探索性阶段。因此,有必要通过数值手段了解预应力路堤的工作状态,以掌握其加固性能。鉴于此,借助ABAQUS软件平台构建预应力路堤仿真系统,分析差异化预应力加固参数对路堤变形和承载能力的影响以及预应力加固构件的受力特征。研究结论:(1)路堤本体段坡面较优加固位置为距本体顶面以下0.3倍本体高度处;(2)坡率1∶1的预应力路堤在第1、2排侧压板分别施加50 k Pa、100 k Pa预压荷载时,其变形与承载力均可达传统路堤(坡率1∶1.5)水平,并可通过提升加固标准进一步强化路堤承载性能;(3)当对第1、2、3排侧压板分别施加50 k Pa、100 k Pa、100 k Pa预压荷载时,路堤内部附加围压S11>13.5 k Pa区域大致呈"x"形分布并形成横贯路堤的"预压加固区";(4)侧压板锚固区受力集中且复杂,应注意保障锚固区板体强度;(5)力筋在路堤加载前后的应力变化量与坡面侧向变形特征相关;(6)本研究成果可为铁路预应力路堤的加固设计提供技术指导。

Numerical Research on the Prestressed Reinforcement Technology of Railway Embankment

Research purposes:Prestressed railway embankment is a newly-developed subgrade reinforcement method;its mechanical and deformation characteristics have not been systematically studied yet,and the corresponding design theory is still under exploration.Therefore,it is necessary to study the working state and reinforcement performance of a prestressed embankment(PE)using numerical simulations.This paper established numerical models of typical PEs using the ABAQUS software platform and further analyzed the deformation and bearing behavior of PEs and the stress characteristics of reinforcement components under different reinforcement parameters.Research conclusions:(1)The optimal reinforcement position is about 0.3 H away from the top surface of the embankment zones below the subgrade beds,where H is the height of the embankment zones below the subgrade beds.(2)The deformation and bearing capacity of a PE(slope ratio 1∶1)with preloading pressures of 50 kPa and 100 kPa applied to the first and second row lateral pressure plates(LPPs),respectively,is approximately equivalent to the corresponding traditional embankment(slope ratio 1∶1.5),and the bearing capacity can be further improved by increasing the prestress reinforcement levels.(3)For the PE with preloading pressures of 50 kPa,100 k Pa and 100 kPa applied to the first,second and third row LPPs,respectively,the internal reinforcement regions that have an additional confining pressure S11 greater than 13.5 kPa approximately present an x-shaped contour and form a preloading reinforcement zone crossing the whole embankment.(4)The stresses at the anchorage zone of a LPP are concentrated and complex,and attention should be paid to ensure the strength of the anchorage zone.(5)Stress variation of a prestressed bar before and after loading on a PE is related to the lateral deformation characteristics of the embankment slope.(6)The research results can provide technical guidance for design of prestress reinforced railway embankments.