摘要
为研究堆石级配对堆石-土工格栅界面剪切特性的影响,根据Einav提出的堆石级配方程配制5种不同级配的堆石试样,进行了设土工格栅加筋与不设土工格栅加筋堆石的界面直剪试验,分析了最大粒径和分形维数对界面抗剪强度以及加筋系数的影响,并给出了加筋系数与堆石平均粒径d;与土工格栅网孔尺寸之比(粒孔比)的关系。试验结果表明,土工格栅的加筋作用主要取决于堆石颗粒与格栅之间的嵌锁作用。当堆石材料中小于格栅网孔尺寸的粗粒含量较高时,嵌锁作用显著,界面抗剪强度增大。反之,当堆石中大于格栅网孔尺寸的粗粒含量较高时,堆石与格栅间的嵌锁作用减弱,滑动作用增强,界面抗剪强度降低。因此,加筋系数随堆石级配最大粒径的增大而减小,随分形维数的增大而增大。此外,加筋系数随粒孔比的增大呈指数衰减,当粒孔比小于0.22时,加筋系数大于1.0,粒孔比大于0.3后,加筋系数趋于0.8。该试验结果对坝顶土工格栅加筋体结构的设计具有重要的参考价值。
In order to study the effect of the interfacial shear characteristics between rockfill materials and geogrid,the interface direct shear tests on the rockfill material with and without geogrid reinforcement are carried with the rockfill material samples prepared with five different gradations in accordance with the gradation equation proposed by Einav(2007),and then the effects of the maximum particle size and fractal dimension on the interfacial shear strength and reinforcement coefficient are analyzed,while the relationship between the reinforcement coefficient and the ratio of mean particle size d;of rockfill material to the aperture size of geogrid(particle-aperture ratio)is given out as well.The experimental results show that the reinforcement effect of geogrid mainly depends on the interlocking effect between the particle of rockfill material and the geogrid.When the content of the coarse particles in the rockfill material with the size less than the aperture size of the geogrid is higher,the interlocking effect is significant along with the increase of the interfacial shear strength.Conversely,when the content of the coarse particle in the rockfill materials with the size larger than the aperture size of the geogrid is higher,the interlocking effect between the rockfill material and the geogrid is to be weakened along with the enhancement of sliding effect and reduction of the interfacial shear strength.Therefore,the reinforcement coefficient is to be decreased along with the increase of the maximum particle size of the gradation of the rockfill material and increased along with the increase of the fractal dimension.Moreover,the reinforcement coefficient is to be exponentially decayed,and then the reinforcement coefficient is to be larger than 1.0 when the particle-aperture ratio is less than 0.22,while it tends to be 0.8 when the particle-aperture ratio is larger than 0.3.The experimental results have important referential values for the design of the reinforced structure on the crest of the dam.
作者
王柳江
刘归华
毛航宇
王珊
沈超敏
WANG Liujiang;LIU Guihua;MAO Hangyu;WANG Shan;SHEN Chaomin(College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,Jiangsu,China;International Joint Laboratory of Long-term Behaviour&Environmentally Friendly Rehabilitation Technologies on Dams,Nanjing 210098,Jiangsu,China;Water Affairs Bureau of Jiangning District of Nanjing,Nanjing 211112,Jiangsu,China)
出处
《水利水电技术（中英文）》
北大核心
2022年第5期82-90,共9页
Water Resources and Hydropower Engineering
基金
国家自然科学基金资助项目(U1765205,51979091,52009036)
中央高校基本科研业务费专项资金(B210204021)。
关键词
堆石材料
土工格栅
界面剪切特性
颗粒级配
直剪试验
rockfill material
geogrid
interfacial shear characteristics
particle gradation
direct shear test
