橡胶砾石级配对筋土界面循环剪切特性的影响  

Influence of Rubber Gravel Grade on the Cyclic Shear Properties of the ReinforcedSoil Interface

作　　者：刘文燕[1] 钱振豪 刘飞禹[1] 冯忞 LIU Wenyan;QIAN Zhenhao;LIU Feiyu;FENG Min(School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,China;Shanghai Pudong Architectural Design and Research Institute Co.,Ltd.,Shanghai 201206,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444 [2]上海浦东建筑设计研究院有限公司,上海201206

出　　处：《防灾减灾工程学报》2024年第5期1158-1167,共10页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(52078285,52378355)资助。

摘　　要：橡胶砾石作为基础填料,具有低剪切刚度、高阻尼比的特性。为了研究土工格栅-橡胶砾石的循环剪切特性,利用室内动态直剪仪进行了一系列直剪试验,分析了4种橡胶砾石颗粒级配(级配不良GR1、GR4,级配良好GR2、GR3)、3种橡胶配比(10%、30%、60%)、3种竖向应力(30、60、90 kPa)下土工格栅-橡胶砾石界面的剪应力-剪切位移关系和体变特性。试验结果表明:在循环剪切过程中,各橡胶砾石级配均表现出剪切硬化的特点,但其抗剪强度与纯砾石相比均出现不同程度的降低;橡胶砾石抗剪强度随着竖向应力的增加而增大,4种级配土中GR2表现出最高的抗剪强度,但相较于纯砾石其抗剪强度约下降9%;界面最大竖向位移与竖向应力和橡胶含量成正相关,2种连续级配土GR2和GR3的界面竖向位移较小;在同一颗粒级配下,剪切频率和剪切位移幅值越大,混合土界面峰值剪应力越大;筋土界面剪切刚度随着循环次数的增加而增大,随着橡胶含量的增大而减小,而阻尼比与剪切刚度呈相反的规律。Rubber gravel,used as base fill,exhibits low shear stiffness and a high damping ratio.To investigate the cyclic shear characteristics of geogrid-rubber gravel,a series of direct shear tests were conducted using a laboratory dynamic direct shear apparatus.The shear stress-shear displacement relationship and volumetric characteristics of the geogrid-rubber gravel interface were performed under four different rubber gravel particle grades(poorly graded GR1 and GR4,well graded GR2 and GR3),three rubber ratios(10%,30%and 60%)and three vertical stresses(30 kPa,60 kPa and 90 kPa).Results revealed that all rubber gravel grades exhibited shear hardening during cyclic shear,but their shear strength decreased to varying degrees compared to pure gravel.Additionally,the shear strength of the rubber gravel increased with increasing vertical stress.Among the four grades,GR2 showed the highest shear strength,though it was still approximately 9%lower than that of pure gravel.The maximum vertical displacement at the interface was positively correlated with both vertical stress and the rubber content,while the continuously graded soils GR2 and GR3 exhibited smaller vertical displacements.Under the same particle grade,higher shear frequency and displacement amplitude led to greater peak shear stress at the mixed soil interface.Furthermore,while the shear stiffness of the reinforcement-soil interface increased with the number of cycles,it decreased as rubber content increased.In contrast,the damping ratio exhibited an inverse relationship with shear stiffness.

关 键 词：筋土界面 水平循环荷载 橡胶砾石 颗粒级配特征 阻尼比 

分 类 号：TU411.7[建筑科学—岩土工程]