摘要
三明治形加筋土是一种在黏土中加入加筋砂层形成的混合填料形式的新型加筋土。为了研究不同条件下三明治形加筋土筋-土界面的动力剪切特性,采用大型直剪仪对三明治形加筋土进行了一系列循环剪切试验,研究了不同薄砂层厚度、循环剪切幅值和竖向应力对界面剪切特性的影响。试验结果表明:筋-土界面的剪应力峰值随着循环次数的增加而增加,循环周次为10时,薄砂层厚度为5、6、7、8、9 mm的条件下,筋-土界面的剪应力峰值分别为24.84、27.4、27.94、26.33、24.68 kPa,表明薄砂层厚度为7 mm时,筋-土界面在循环剪切阶段的峰值剪应力最大;剪切幅值越大,界面循环剪切的最终剪缩量越大,同一循环次数对应的剪切刚度和阻尼比越小;在不同竖向应力下,界面在循环剪切过程中都发生了循环剪切硬化现象,循环周次为10时,竖向应力为30、60、90 kPa的条件下,筋-土界面的剪应力峰值分别为20.4、25.14、32.96 kPa,表明剪应力峰值随竖向应力的增大而增大,同一循环次数对应的剪切刚度也随竖向应力的增大而增大。
A new-style sandwich reinforced soil is clay reinforced with geogrid encapsulated in thin layers of sand. To investigate the interfacial shear behavior of sandwich reinforced soil, a series of cyclic shear tests was performed through a large-scale direct shear device. The influence of thickness of sand layer, shear amplitude and normal stress on the interface shear behavior were investigated. Results indicated that the peak shear stress of the interface increased with the increase of cycle number. When the thickness of sand layers were 5, 6, 7, 8, 9 mm in the last cycle number, the corresponding peak shear stresses of the interface were 24.84, 27.4, 27.94, 26.33, 24.68 kPa, respectively, showing the maximum peak shear stress of the interface occurred with 7 mm of the thickness of thin sand layer. The ultimate vertical displacement increased with the increase of cyclic shear amplitude, and shear stiffness and damping ratio of the interface decreased with the increase of cyclic shear amplitude at the same cycle number. When the normal stresses were 30, 60, 90 kPa, in the last cycle number, the corresponding peak shear stresses of the interface were 20.4, 25.14, 32.96 kPa, respectively, showing the peak shear stress increased with the increase of normal stress, and the shear stiffness increased with the increase of normal stress at the same cycle number.
作者
刘飞禹
施静
王军
蔡袁强
LIU Fei-yu;SHI Jing;WANG Jun;CAI Yuan-qiang(Department of Civil Engineering, Shanghai University, Shanghai 200444, China;College of Architecture and Civil Engineering, Wenzhou University, Wenzhou, Zhejiang 325035, China;Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province, Wenzhou University, Wenzhou, Zhejiang 325035, China;Innovation Center of Tideland Reclamation and Ecological Protection, Wenzhou University, Wenzhou, Zhejiang 325035, China;College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang 310000, China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第6期1991-1998,共8页
Rock and Soil Mechanics
基金
国家自然科学基金(No.51478255
No.51678352
No.51622810
No.51278383)
上海市自然科学基金(No.14ZR1416100)
科技部国家重点研发计划(No.2016YFC0800203)
科技部国际合作专项(No.2015DFA71550)~~
关键词
加筋土
循环剪切
剪切刚度
阻尼比
reinforced soil
cyclic direct shear test
shear stiffness
damping ratio
