高摩阻超静定土工格栅在粗粒土夹层中的剪胀作用研究  

On the role of dilatancy induced by high resistance hyperstatic geogrids in coarse-grained soil layer

作　　者：崔新壮[1,2] 姜鹏 王艺霖[3] 金青 陈璐[4] CUI Xin-zhuan;JIANG Peng;WANG Yi-lin;JIN Qing;CHEN Lu(School of Civil Engineering,Shandong University,Jinan,Shandong 250061,China;School of Civil Engineering,Chongqing University,Chongqing 400045,China;Department of Civil and Environmental Engineering,the Hong Kong University of Science and Technology,Hong Kong,China;School of Civil Engineering,Binzhou University,Binzhou,Shandong 256603,China)

机构地区：[1]山东大学土建与水利学院,山东济南250061 [2]重庆大学土木工程学院,重庆400045 [3]香港科技大学土木与环境工程系,中国香港 [4]滨州学院建筑工程学院,山东滨州256603

出　　处：《岩土力学》2024年第1期141-152,共12页Rock and Soil Mechanics

基　　金：国家重点研发计划(No.2022YFB2601900);国家自然科学基金(No.52027813,No.52178429,No.U22A20235);山东省自然科学基金(No.ZR2020ME242)。

摘　　要：在加筋土工程中,采用异型格栅和设置粗粒土夹层可以有效增强筋土相互作用。然而粗粒土夹层厚度的确定方法仍有待进一步研究。基于一种带有凸起节点结构的高摩阻超静定土工格栅(high resistance hyperstatic geogrids,简称HRHG)与砾石的直剪试验结果,建立了剪切硬化筋土界面的剪胀本构模型,并进一步研究了筋土剪胀应力在土体内引起附加应力的分布规律。通过开展不同法向压力(30、50、80 kPa)下的直剪试验,研究了不同粗粒土夹层厚度(60、100、140、180 mm)对筋土相互作用的影响,并与筋土界面剪胀应力的分布规律进行了对比分析。结果表明,筋土界面剪胀本构模型可以有效计算剪缩位移和剪胀位移,且最终剪胀位移随法向压力增加而减小。由界面剪胀应力引起的粗粒土中附加应力随着与筋土界面距离的增加而降低,但是剪胀范围逐步增大。粗粒土夹层厚度的增加可以有效提高界面剪切强度,但存在最优夹层厚度使界面剪切强度的增幅迅速降低。最优夹层厚度随着法向压力的增加而减小。通过对比分析最优夹层厚度与剪胀应力比之间的关系,提出了基于筋土界面剪胀本构模型的确定最优夹层厚度的半经验公式,可为HRHG在工程中的设计或应用提供参考。In geosynthetic reinforced soil engineering,the interaction between reinforcement and soil can be effectively enhanced by the use of geosynthetics with additional structures and the setting of coarse-grained soil layers.However,the determination method of the thickness of coarse-grained soil layer is still unclear.In this paper,based on the results of direct shear tests on the high resistance hyperstatic geogrids(HRHG)designed with convex nodes and gravel,a constitutive model of dilatancy at the geogrid-gravel interface under shear hardening condition is established,and the distribution of the additional stress induced by dilatancy in reinforced soil is further investigated.By conducting direct shear tests under different normal pressures(30,50,80 kPa).The effects of different coarse-grained soil layer thicknesses(60,100,140,180 mm)on the interaction between reinforcement and soil are evaluated,and the dilatancy distribution at the interface between reinforcement and soil is also compared and analyzed.The results show that the established constitutive model for geogrid-gravel interfacial dilatancy agreed well with direct shear test results,suggesting that it can effectively calculate the shear shrinkage and dilatancy,and the final dilatancy decreases with the increase of normal pressure.The additional stress in coarse-grained soil layer induced by interfacial dilatancy decreases with increasing distance from the geogrid-gravel interfaces,but the scope of dilatancy increases gradually.The increase of the thickness of coarse-grained soil layer can effectively improve the interfacial shear strength,but there exists an optimal layer thickness,which rapidly reduces the increase of interfacial shear strength.The optimal layer thickness decreases with the increment of normal pressare.Through the comparative analysis of the optimal layer thickness and dilatancy ratio,a semi-empirical formula for determining the optimal layer thickness based on the modified dilatancy constitutive model is put forward,which can provide a r

关 键 词：超静定土工格栅 筋土相互作用 直剪试验 剪胀应力 粗粒土夹层 

分 类 号：TU411[建筑科学—岩土工程]