剑麻纤维/砂土复合材料三轴剪切强度特性  

Triaxial Shear Strength Characteristics of Sisal Fiber/Sand Composite Material

作　　者：武立林 钱卫[1] 刘瑾[1] 张化鹏 WU Lilin;QIAN Wei;LIU Jin;ZHANG Huapeng(School of Earth Sciences and Engineering,Hohai University,Nanjing,Jiangsu 210000,China)

机构地区：[1]河海大学地球科学与工程学院,江苏南京211100

出　　处：《河北工程大学学报（自然科学版）》2020年第4期26-33,共8页Journal of Hebei University of Engineering:Natural Science Edition

基　　金：国家重点研发计划项目(2018YFC1508501);江苏省水利科技项目(2017010)。

摘　　要：为改善砂土的抗剪强度特性,针对剑麻纤维加筋砂土复合材料,通过一系列不固结不排水三轴试验,对不同纤维掺量、纤维长度和砂土干密度条件下剑麻纤维/砂土复合材料的剪切强度特性进行深入研究,并对剑麻纤维加筋机制进行分析。试验结果表明:复合材料中纤维相对含量改变时,初始刚度变化不大;适量的纤维掺量和纤维长度可以在砂体内形成三维网状结构,对比未加筋试样黏聚力显著提高,表明纤维加筋可有效提高砂土的抗剪强度;由于密度增加使得剪切过程中纤维与砂颗粒间的咬合和滑动摩擦力增加使复合材料抗剪强度显著提高;围压增加纤维与砂土界面有效接触面积导致砂土抗剪强度与峰值偏应力明显增强。采用剑麻纤维加筋砂土可增强砂土间界面作用力,明显改善砂土抗剪强度特性。In order to improve the shear strength characteristics of sand,it is aimed at sisal fiber reinforced sand composite material in this paper.The effect of fiber content,fiber length and dry density on the shear characteristics of reinforced sand was thoroughly studied by unconsolidated-undrained triaxial shear test so as to investigate the reinforcement mechanism of fiber-reinforced sand.The test results show that fiber reinforcement has little effect on the initial stiffness of sand.Appropriate fiber content and fiber length can form a three-dimensional network structure in sandy soil,which higher than that of unreinforced samples.It shows that fiber reinforcement can effectively improve the shear strength of sand.The shear strength of the composite material increases significantly due to the increase in the bite and sliding friction between the fiber and sand particles in the shear process.The increase of confining pressure on the effective contact area between fiber and sand results in the increase of shear strength and peak deviatoric stress.Sisal fiber reinforced sand can enhance the interfacial force between sand and improve the shear strength of sand.

关 键 词：剑麻纤维 复合砂土材料 三轴试验 剪切特性 破坏应力 

分 类 号：TU441[建筑科学—岩土工程]