肋板形状对肋板式挡墙稳定性影响试验分析

Experiment for the influence of rib shape on the stability of ribbed slab retaining wall

肋板式挡墙是一种依靠肋板与肋板间土体的摩擦效应平衡墙背土压力的新(轻)型支挡结构,其稳定性受肋板形状的影响显著。开展由纸质肋板和有机玻璃面板构成的肋板式挡墙砂箱模型试验,研究3种典型肋板形状对肋板式挡墙稳定性影响规律,分析在极限稳定状态下肋板形状与肋板面积的内在关系。试验结果表明:肋板形状为上小下大的正立三角形肋板面积最小,其次为上大下小的倒三角形肋板,而矩形时所需的肋板面积最大。相对于矩形肋板,正立三角形肋板的面积节约率均值约为25.5%,底部约束的倒三角形肋板约为12.7%,倒三角形肋板约为6.3%;矩形、正立三角形和底部约束的倒三角形肋板式挡墙均为绕墙趾转动的倾覆破坏模式,倒三角形肋板式挡墙则随肋板间距减小由沿墙底滑移破坏模式转变为倾覆破坏;墙体肋板布置间距由疏至密变化,处于极限稳定状态的肋板式挡墙所需肋板长度呈非线性减小趋势,最终趋于稳定。

The ribbed slab retaining wall is a new and light retaining structure, which balances the earth pressure behind the wall by friction effect caused by the ribs and soil mass. The stability of the ribbed slab retaining wall is significantly affected by the shape of the ribs. This paper analyzed the intrinsic relationship between ribs and its area under the limit stable state by a sandbox model of ribbed retaining wall. The result shows that: the smallest area of ribs is the up triangular, and the second is the down triangular, and the rectangular is the largest. Compared with the rectangular rib, the up triangular saves area about 25.5%, the bottom constrained down triangular rib saves about 12.7%, and the down triangular rib saves about 6.3%. Besides, failure mode of the rectangular, the up triangle and the bottom constraint down triangle ribbed retaining wall is overturn around the wall foot, and the down triangular ribbed retaining wall changes from slippage mode along the bottom of the wall to overturning failure with the decrease of rib spacing. With the rib spacing becoming bigger, the length of rib required for the ribbed retaining wall in limit stable state tends to decrease in nonlinear and eventually to be stable.