抗滑桩-加筋土挡墙组合支挡结构开发

Development of combined retaining structure composed of anti-slide pile and reinforced earth retaining wall

针对山区陡坡地形上加筋土挡墙抗滑稳定性的不足,提出抗滑桩+刚/柔组合墙面加筋土挡墙组合支挡结构,阐述该组合支挡结构的研发思路、结构形式和技术特征。采用有限差分程序FLAC3D建立该组合支挡结构的数值模型,对比分析抗滑桩和抗滑桩+承台2种结构的加筋土挡墙墙面水平位移、抗滑桩位移和桩身弯矩、土工格栅拉力及路基稳定性,重点探讨抗滑桩桩长、覆盖层模量和上覆荷载的影响。研究结果表明:在抗滑桩顶部设置承台可以有效减小墙面和桩身水平位移,提高路基稳定性;将抗滑桩和承台的连接方式由刚接改成铰接会使桩身弯矩显著减小,而对墙面和桩身位移及路基稳定性影响不大;未设置承台时墙面和桩身水平位移更容易受到抗滑桩桩长、覆盖层模量和上覆荷载变化的不利影响。

A combined retaining structure(CRS)composed of anti-slide pile and reinforced earth retaining wall with flexible/rigid facings was proposed to improve the stability of reinforced earth retaining wall constructed on steep terrain of mountainous areas.The development process,structural style,and technical features of CRS were introduced.The finite difference program FLAC 3D was adopted to establish the numerical models of CRS.The horizontal displacement of facing of reinforced earth retaining wall,the displacement and bending moment of anti-slide pile,the tensile force of geogrid and the stability of subgrade of two cases,namely,anti-slide pile only and anti-slide pile connecting with bearing platform,were compared and analyzed.The influence of the length of anti-slide pile,the modulus of overburden and the surcharge load was also intensively explored.The results show that the horizontal displacements of the wall facing and anti-slide pile could be effectively reduced with a bearing platform installed on the anti-slide pile,and the stability of subgrade is also improved.The bending moment of anti-slide pile decreases significantly when the connection between the anti-slide pile and bearing platform is changed from rigidity to a hinge joint,while little effect on the displacements of wall facing and anti-slide pile and the stability of subgrade is obtained.The horizontal displacements of the wall facing and anti-slide pile of the case without bearing platform are easily affected by the variation of the length of anti-slide pile,the modulus of overburden and the surcharge load.