模型土工格栅应变测量方法研究

Strain sensing method of geogrid in centrifugal model test

文章采用高密度聚乙烯塑料窗纱作为模型土工格栅,进行1组加筋边坡离心模型试验;通过在模型土工格栅表面涂抹环氧树脂条带并粘贴应变片的方法,并根据拉力标定试验换算得到的筋材内力,监测模型试验过程中筋材应力分布,研究加筋边坡填筑过程中筋材应力分布规律。研究结果表明:环氧树脂条带与柔性703胶条相比,黏结效果稳固,对高密度聚乙烯塑料窗纱模型材料具有良好的适应性;采用环氧树脂条带粘贴应变片测量筋材内力,测量结果较好反映了加筋边坡的筋材应力分布,测试方法可行;下部坡体偏软弱时坡体在上覆荷载作用下将发生侧向挤出边坡失稳,加筋体内部坡脚至H/3(H为坡高)高度形成潜在滑动面。研究成果对于优化筋材测量方法、探究筋-土相互作用机理具有一定意义。

In this paper,high density polyethylene(HDPE)window screen is used as model geogrid to carry out a group of centrifugal model tests on reinforced slope.Through the method of coating epoxy resin strips on the surface of model geogrid and pasting strain gauges,and according to the internal force of reinforcement converted from tensile calibration test,the stress distribution of reinforcement in the process of model test is monitored,and the stress distribution law of reinforcement in the process of reinforced slope filling is studied.The results show that compared with flexible 703 adhesive tape,the bonding effect of epoxy resin tape is stable,and it has good adaptability to HDPE window screen model material;the stress distribution of the reinforced slope is well reflected by the measurement results,and the test method is feasible;the lower slope is weak,and the slope will be squeezed out laterally under the overlying load,and the potential sliding surface will be formed from the slope toe to the height of H/3(H is the slope height).The research results are of significance to optimize the reinforcement measurement method and explore the mechanism of soil-reinforcement interaction.