秸秆纤维加筋黄土三轴剪切特性试验  

Experimental Study on Triaxial Shear Properties of Straw Fiber Reinforced Loess

作　　者：张琬 丁九龙[1] 李波 陈泽一 薛一峰[2] 赵玮[2] ZHANG Wan;DING Jiu-long;LI Bo;CHEN Ze-yi;XUE Yi-feng;ZHAO Wei(School of Civil Engineering and Architecture,Xi’an University of Technology,Xi’an 710048,China;Hydropower Engineering Branch,Shaanxi Province Institute of Water Resources and Electric Power Investigation and Design,Xi’an 710001,China)

机构地区：[1]西安理工大学土木建筑工程学院,西安710048 [2]陕西省水利电力勘测设计研究院水电工程分院,西安710001

出　　处：《长江科学院院报》2024年第1期136-142,共7页Journal of Changjiang River Scientific Research Institute

基　　金：国家自然科学基金项目(42007264);陕西省自然科学基础研究计划项目(2023-JC-QN-0630)。

摘　　要：为了探明秸秆纤维加筋黄土的剪切力学特性,开展三轴剪切试验和电镜扫描试验,研究纤维掺量、纤维长度和土体含水率对秸秆纤维加筋黄土应力-应变特性和抗剪强度的影响,并分析加筋机理。结果表明:加入秸秆纤维主要通过增加土体黏聚力以有效提升黄土的抗剪强度,但不会改变黄土偏应力-应变曲线的类型及特征,仍表现为应变硬化型;秸秆纤维的最佳掺量和长度分别为0.3%和10 mm,当纤维掺量和长度超过最佳值时,土体中存在过多的软弱结构面会削弱加筋土体的整体性,筋土间黏结和摩擦作用降低,土体抗剪强度减小;加筋黄土的最佳含水率为素黄土的最优含水率,含水率超过最佳值后,筋土表面结合水膜增厚,筋土间润滑作用增强、摩擦力减弱,土体抗剪强度降低。To investigate the shear mechanical properties of straw fiber reinforced loess,we conducted triaxial shear tests and scanning electron microscopy tests.These tests aimed to examine the influence of fiber content,fiber length,and soil moisture content on the shear-strain characteristics and shear strength of the reinforced loess,as well as the reinforcing mechanism.The results of the tests demonstrate that the addition of straw fibers significantly enhances the shear strength of loess by increasing soil cohesion.Importantly,the admixture of straw fibers does not alter the type and characteristics of the deviatoric stress-strain curve of loess,which remains strain-hardening in nature.Through further analysis,we determined that the optimal values for fiber content and length are 0.3%and 10 mm,respectively.Beyond these optimal values,an excessive number of weak interfaces within the soil mass would weaken the integrity of the reinforced loess.Consequently,the bond and friction between the fibers and soil decrease,leading to a decline in the shear strength of the reinforced loess.Additionally,we found that the best moisture content for reinforced loess coincides with the optimal moisture content of pure loess.However,if the moisture content of reinforced loess exceeds this optimal value,a thickening water film forms on the surfaces of the fibers and soil.This,in turn,increases lubrication and reduces friction between the fibers and soil,ultimately resulting in a decrease in the shear strength of reinforced loess.

关 键 词：加筋黄土 秸秆纤维 三轴剪切试验 电镜扫描 力学特性 

分 类 号：TU54[建筑科学—建筑技术科学]