基于数字图像分析的土工合成材料加筋砂土拉拔试验研究  

Pull-out test on geosynthetic reinforced sand based on digital image analysis

作　　者：王家全[1,2] 祁航翔 林志南 唐毅[1,2] WANG Jia-quan;QI Hang-xiang;LIN Zhi-nan;TANG Yi(College of Civil and Architectural Engineering,Guangxi University of Science and Technology,Liuzhou,Guangxi 545006,China;Guangxi Zhuang Autonomous Region Engineering Research Center of Geotechnical Disaster and Ecological Control,Guangxi University of Science and Technology,Liuzhou,Guangxi 545006,China)

机构地区：[1]广西科技大学土木建筑工程学院,广西柳州545006 [2]广西科技大学广西壮族自治区岩土灾变与生态治理工程研究中心,广西柳州545006

出　　处：《岩土力学》2022年第12期3259-3269,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.41962017);广西自然科学基金重点项目(No.2022GXNSFDA035081);广西高等学校高水平创新团队及卓越学者计划项目(桂教人才[2020]6号);广西研究生教育创新计划项目(No.YCSW2021310)。

摘　　要：由于加筋土界面作用的复杂性,加筋土工程建设中铺设土工格栅时往往采用经验的方法,很大程度上造成了土工格栅的浪费及工程安全隐患,理清不同填料筋土界面作用的影响范围,有助于确定加筋土结构的合理加筋间距。为了揭示不同填料筋土界面作用的影响范围,采用4种不同类型的砂土与格栅在不同法向应力下进行了一系列的拉拔试验,并结合数字图像量测技术,分析了不同类型砂土下界面剪切带厚度、颗粒位移矢量、格栅拉拔阻力峰值及应变等演变规律。研究表明:界面剪切带厚度H随法向应力σv与砂土平均粒径d50的增加而增大,通过多变量拟合的方法,得到了H、σv与d50三者之间的函数表达式;格栅在拉拔过程中,砂土颗粒位移矢量以土工格栅为界有着显著的差别,格栅上部的颗粒位移矢量明显大于下部颗粒,且在格栅上下一定范围内会形成颗粒位移矢量集中带;拉拔阻力峰值随σv及d50的增加而增大;不同类型砂土各区段的格栅应变均表现出由前向后依次递减的趋势。Due to the complexity of the reinforced soil interface, the empirical methods are often used when laying geogrid in reinforced soil engineering construction, which largely causes the waste of geogrids and engineering safety hazards. Clarifying the influence range of the interfacial action of reinforced soil with different fillers is helpful to determine the reasonable reinforcement spacing of reinforced soil structures. In order to reveal the influence range of interface action between reinforcement and soil of different fillers, a series of pull-out tests was carried out with four types of sand and geogrid under different normal stresses. By combining with digital image measurement technology, the evolution laws of interfacial shear band thickness, particle displacement vector, peak pullout resistance, and strain of geogrid for different types of sand were analyzed. The results show that the thickness of interfacial shear band H increases with the increase of normal stress σvand the average particle size of sand d50. Through the multivariate fitting method, the function expressions among the thickness of the interfacial shear band H, the normal stress σvand the average particle size of the sand d50are obtained. In the pull-out process of geogrid, the displacement vector of sand particles is significantly different when the geogrid is taken as the boundary. The displacement vector of particles above the geogrid is significantly larger than that below the geogrid, and there is a concentration band of particle displacement vectors in a certain range above and below the geogrid. The peak pullout resistance increases with the increase of normal stress σv and the average particle size of sand d50. The geogrid strain of each section of different types of sand shows a decreasing trend from the front to the rear.

关 键 词：砂土类型 拉拔试验 格栅应变 界面剪切带 位移矢量 

分 类 号：TU431[建筑科学—岩土工程]