两类拉筋的对拉薄壁面板式路堤挡墙性能对比分析

Comparison Analysis of Performance of Thin Panels Mutually Anchored by Geogrids and Steel Bars in Reinforced Embankments

为探究钢拉筋和土工格栅加筋的对拉薄壁面板式路堤挡墙的性能差异,采用FLAC3D数值模拟软件分析了不同填土高度的拉筋拉应力、面板水平位移和侧向土压力,同时结合施工难易程度、结构耐久性、经济性等因素对两种路堤进行比较,结果表明:(1)在高填方(填土高度10~12 m)情况下,土工格栅式拉筋面板中部出现显著外鼓变形;钢筋式拉筋面板顶部与底部外伸位移较大、中部则向内凹,其变位模式与前者相反;(2)相比于土工格栅,钢筋承受拉力更大,面板所受侧向土压力也较大;路堤填土高度达到6 m以上时,钢筋在底层两端部所受拉力最大;(3)钢拉筋比土工格栅拉筋对面板的侧向变形控制能力强,侧向位移约为土工格栅拉筋的1/10;但钢拉筋与面板节点施工控制要求较高,且长期防腐蚀性难以保障,耐久性、经济性、路堤易压实性等均弱于土工格栅拉筋,而土工格栅拉筋因其面板侧向变形控制能力较弱,一般不适于较高填方(6 m以上)。为便于施工,可采用对拉包裹式加筋土挡墙,装饰面板独立于其后填料。

In order to investigate performance similarities and differences of thin panels mutually anchored by geogrids and steel bars in reinforced embankments,tensile stress of the reinforcements,horizontal displacements of the panels and lateral earth pressure on them are analyzed using FLAC3D numerical simulation method under varying embankment height.Meanwhile,construction operability,service durability and effective cost of the two structures are generally compared.The results show that:(1)As for embankments with 10m to 12m heights,the middle of the panel pulled by geogrids clearly bulges out;On the contrary,the middle of the panel pulled by steel bars concaves inward and displacements of its top and bottom are relatively larger than the middle.(2)Compared with the geogrids,steel bars bear higher tension force,and lateral earth pressure on their panels is correspondingly larger.The steel bars suffer the maximum tension at the two ends of the bottom layer if the embankment height reaches more than 6m.(3)The deformation of the panels anchored by steel bars is much less than that by geogrids,and the former is about 1/10 of the latter.But for the former,construction requirements of joints between the bars and the panels are too rigorous,and their long-term corrosion protection is difficult to potentially cause worse service durability than the geogrids.Besides,in terms of effective cost of the structure and compressibility of the backfills,the former is also not as good as the latter.However,as for controlling lateral deformation of the panels,the geogrids are worse than the steel bars,and they are accordingly not more suitable for the embankments with more than 6 m heights.For construction convenience,a two-side package-pulling type reinforcement retaining wall can be used with decorative panels independent of the filling.