离心模型试验中土工格栅拉力测量  

TENSION MEASUREMENT OF GEOGRID IN CENTRIFUGAL MODEL TEST

作　　者：俞松波[1] 沈明荣[1,2] 陈建峰[1,2] 叶铁锋[1] 石振明[1,2] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩石力学与工程学报》2008年第11期2295-2301,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50508030);上海市重点学科建设项目资助(B308)

摘　　要：选用高密度聚乙烯制成的三维土工网夹层作为模型土工格栅,进行一组软土地基上加筋路堤的离心模型试验。通过浇注的环氧树脂带应变测试与图像分析相结合的方法,研究路堤填筑过程中加筋材料拉应力的发展与分布。对环氧树脂分别进行了连续加载和分级加载标定试验,并提出相应的线弹性模型和广义开尔文模型。试验结果表明:(1)广义开尔文模型能较好地描述环氧树脂的力学特性,引进的时间因子使其能适用于不同拉伸速率的拉力计算;(2)线弹性模型未考虑环氧树脂的蠕变变形,弹性模量因加载速率不同而有所差异,故其无法准确计算路堤施工过程中的筋材拉力,试验的计算值平均偏大16%;(3)图像分析与应变测试具有较好的一致性,其偏差与位移大小和方向有关。A centrifugal test was conducted on a reinforced embankment on soft clay using the interlayer of a three-dimensional geonet, which was made of high density polyethylene（HDPE） as model geogrid. In combination with the analysis of the photographs taken in flight, the development and distribution of tensions of the model grid were obtained. The strain gauges with epoxy resin were calibrated through continuous loading and multi-stage loading tensile test; and then elastic model and generalized Kelvin model were used to describe the characteristics, respectively. The experimental results show： （1） generalized Kelvin model is suitable to describe the mechanical properties of epoxy resin with the time factor; （2） as the stage of creep process has not been considered, the tension calculated by elastic model is approximately 16% greater than calculated by generalized Kelvin model, and the deviation is varied with the extension rate; and （3） the tension calculated based on the observed photographs is in agreement with that based on the measured strain. It is found that the accuracy depends on the displacement direction and magnitude.

关 键 词：土力学 加筋路堤 离心试验 土工格栅 应变片 环氧树脂 

分 类 号：TU41[建筑科学—岩土工程]