加筋土挡墙－抗滑桩组合支挡结构数值模拟

摘要

针对软弱土层上方高填方路堤的填筑问题，提出了一种加筋土挡墙－抗滑桩组合支挡结构。采用有限差分软件FLAC3D建立加筋土挡墙－抗滑桩组合支挡结构数值分析模型，着重分析了不同面板浇筑方式对加筋土挡墙墙面水平位移、墙背土压力、桩身水平位移、桩身弯矩和土工格栅应力分布的影响。模拟结果表明：后浇式刚性面板组合支挡结构的墙面水平位移呈线性分布，最大位移出现在墙顶；所受土压力远小于刚性面板；桩身水平位移和弯矩均较大。刚性面板组合支挡结构的土工格栅最大拉应力出现在面板与格栅连接处，而后浇式刚性面板组合支挡结构土工格栅最大拉应力随着层高的增加，出现位置距离挡墙越远。后浇式刚性面板组合支挡结构由于其面板位移和受力较小，性能良好，故其适合在软弱土高填方地区推广使用。%A composite retaining structure composed of reinforced soil retaining wall and anti-slide piles is proposed to solve the construction problems in high fill embankment upon soft soil.Finite difference software FLAC3D was used to establish the numerical models of composite retaining structure.The influences of cast mode of panels on lat-eral displacement of wall surface,lateral earth pressure behind retaining walls,lateral displacement and bending mo-ments of anti-slide piles and stress distribution of geosynthetic geogrids were analyzed.Numerical results revealed a linear distribution of lateral displacement of panels in post-cast rigid mode and the maximum displacement at the top of walls.Earth pressure on post-cast panels was far less than that on rigid panels.Moreover,the displacement and bending moments of anti-slide piles in the composite retaining structure with post-cast rigid panels were larger than those in the structure with rigid panels.The largest tensile stress of geosynthetic geogrids in the structure with rigid panels was found at the junction between panels and geogrids;while for the structure with post-cast rigid panels,the position of the largest tensile stress deviated from the retaining wall as the layer of geogrids were higher.Composite retaining structure with post-cast rigid panel could be used and promoted in high embankment area on soft soil due to its good performance with small displacement and earth pressure on post-cast panel.