斜坡地段预应力锚杆-加筋土组合支挡结构力学行为

Mechanical behavior of prestressed anchor-reinforced soil combined retaining structure in slope area

针对斜坡地段加筋土挡墙变形过大和稳定性不足的问题,开发了一种适用于斜坡路基的预应力锚杆-加筋土组合支挡结构.为验证预应力锚杆的引入对加筋土结构的性能提升,明确组合支挡结构承载特性,设计完成了斜坡区域加筋土挡墙和组合支挡结构静力模型试验,对比分析了两种结构响应差异.试验结果表明:相较于加筋土挡墙,组合支挡结构能更好地限制面板位移,控制墙顶沉降;墙底中部土压力显著减小且整体分布均匀,因此能适应更广泛的地基条件;回填土-原位坡体界面抗滑力更高,且能够避免该界面拉应力区的产生;预应力锚杆分担了附加荷载,格栅应变显著减小;加筋土挡墙潜在破裂面形状与朗肯破裂面一致,而组合支挡结构为双折线潜在破裂面.试验初步验证了组合支挡结构的优越性.

Facing the problems of excessive deformation and insufficient stability of reinforced soil retaining wall in slope area,a prestressed anchor-reinforced soil combined retaining structure for embankment in slope area was developed.To confirm the reinforcement effect associated with the prestressed anchors and to clarify the mechanical behavior of the combined retaining structure,scaled physical model tests were conducted for both the traditional reinforced soil retaining wall and the newly developed combined retaining structure.Deformation,earth pressure,reinforcement strain,and the potential failure surface were compared and analyzed.The results demonstrate superior lateral deformation and settlement control of the combined retaining structure compared to the reinforced soil retaining wall.The earth pressure at the bottom of combined retaining structure is reduced and evenly distributed,indicating higher compatibility under weaker underlying conditions.The horizontal confining effect induced by the prestressed anchors improves the interface resistance between the backfill and the preexisting slope and prevents the generation of a tensile pressure zone at the interface.Additionally,the strains of the geogrid are significantly reduced because the prestressed anchors share part of the load,and it is observed that the potential failure surface is transformed from the Rankine type(for the traditional reinforced soil retaining wall)to the bifold type(for the prestressed anchor-reinforced soil combined retaining structure).The tests results verified the superiority of the combined retaining structure.