返包式土工格栅加筋土挡墙动态行为研究

Research on Dynamic Behavior of Geogrid Reinforced Soil Retaining Wall with Wrapped Face

为研究返包式土工格栅加筋土挡墙在高速铁路列车荷载作用下的受力变形行为和作用机理,本文利用室内大型模型试验进行加筋土挡墙墙体加速度、动土压力、墙面变形、残余土压力及土工格栅拉伸应变等分布规律的研究。试验结果表明:加筋土挡墙内部竖向加速度受加载频率影响较大,加载频率10 Hz时加速度突然增大;墙面累积水平位移沿墙高呈S形分布,随着应力增大,水平位移最大值位置从墙中部逐渐向中下部移动;动土压力主要受动荷载大小及加载次数影响,沿墙高呈衰减趋势;动载卸载后残余土压力较小,经过增长后逐渐趋于稳定;筋材累积应变在填筑-静载-动载过程中呈增加-稳定-减小-稳定的趋势,沿拉筋长度方向呈单峰值或双峰值分布,峰值位置从高到低距墙面水平距离逐渐减小。

In order to study the stress deformation behavior and mechanism of action of geogrid reinforced soil retaining wall with wrapped face under high speed railway train loads,a study on the distribution of accelerated velocity,dynamic soil pressure,deformation of wall face,residual soil pressure and tension strain of geogrids of reinforced soil retaining wall,was done through the large scale model test in the laboratory.Test results showed that,the vertical accelerated velocity inside the reinforced soil retaining wall was greatly affected by load frequency and increased suddenly at the load frequency of 10 Hz.The cumulative lateral displacement of wall face showed ＂S＂-shaped distribution along the wall height,and the location of max-value of lateral displacement gradually moved to the lower section from the middle section with the increasing of the dynamic load.The dynamic soil pressure,which showed the trend of attenuation down the wall height,was largely affected by the magnitude and the number of dynamic loads.The residual soil pressure after the unloading of dynamic load was small,and tended to be stable after increase.The cumulative strain of geogrids demonstrated a trend of increasing-stabilizing-decreasing-stabilizing in the process of the whole test of filling-static load-dynamic load process,showing single-peak or twin-peak distribution along the geogrid length.The horizontal dis-tance from the max-value position to the wall foot gradually decreased down the wall height.