带齿格栅加筋挡墙工作机理的数值模拟研究

Numerical Simulation of Working Mechanism of Retaining Wall Reinforced with Denti-geogrid

采用数值模拟方法对带齿格栅加筋挡墙工作机理进行了研究,分析了其工作性态及其影响因素,提出了带齿格栅概化模型和极限拉拔力计算公式。研究表明:由于齿筋的存在,格栅水平位移较小,齿筋内侧尤为显著。有齿筋时,位移场梯度明显较大。位移场核心位于齿筋外侧25 cm左右,水平位移峰值约为3 cm。当齿筋离模型箱侧边界距离约3 m时,拉拔力达到峰值。当齿筋间距增大时,其作用长度将逐步开展,拉拔力随之增大。齿筋高度与拉拔力呈正相关,而厚度的改变影响极小。带齿格栅工作机理可大致由挤密阶段、绕流阶段和稳定阶段来加以描述。由概化模型求得的极限拉拔应力理论值与数值模拟结果相近,表明该模型具有一定合理性。

In order to explore the working mechanism of retaining wall reinforced with denti-geogrids, numerical simulation is performed. The working behaviors and the influencing factors are analyzed, the generalized model of denti-geogrid is suggested, and the ultimate pullout force calculation formula is proposed. The research shows that （1） because of the denti-strips, the horizontal displacement of inner segment of geogrid is relatively smaller, especially on inner segments of denti-strips ; （ 2 ） the displacement field gradient of denti-geogrid is obviously larger, the displacement field core locates at about 25 cm out of the denti-strip, and the peak value of horizontal displacement is about 3 cm ; （3） the pullout force reaches peak when the denti-strip is about 3 m distant from lateral boundary of model box, the effective span extends and the pullout force grows when the denti-strip spacing increases, denti-strip height is positive correlated with pullout force while the influence of thickness is insignificant; （4） the working mechanism of denti-geogrid could be described roughly by 3 processes such as compaction, detour flow and stabilization; （5） the calculation values of ultimate pullout force obtained from generalized model are close to numerical test result, thus the rationality of suggested model is verified.