减载伸长路径下棕榈纤维加筋砂力学响应  

Mechanical Response of Palm Fiber-reinforced Sand under Reduced Extensional Path

作　　者：刘昆钰 唐玉肖 刘问[2] 刘学彦[2] 魏少伟 刘睿迪 LIU Kun-jue;TANG Yu-xiao;LIU Wen;LIU Xue-yan;WEI Shao-wei;LIU Rui-di(Yunnan Construction Investment Holding Group Co.,Ltd.,Kunming 650000,China;School of Water and Soil Conservation,Beijing Forestry University,Beijing 100083,China;Railway Engineering Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China;Beijing Tieke Special Engineering Technology Co.,Ltd.,Beijing 100081,China)

机构地区：[1]云南省建设投资控股集团有限公司,昆明650000 [2]北京林业大学水土保持学院,北京100083 [3]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081 [4]北京铁科特种工程技术有限公司,北京100081

出　　处：《科学技术与工程》2024年第18期7792-7803,共12页Science Technology and Engineering

基　　金：云南省交通运输厅科技项目([2018]39)。

摘　　要：为探究棕榈纤维对石英砂力学性能的增强作用,采用减载三轴伸长试验方法测试了饱和状态下棕榈纤维加筋石英砂的剪切力学性能,计算了棕榈纤维加筋石英砂在不同纤维长度和掺量下的应力-应变曲线、初始弹性模量和割线模量,基于摩尔库伦准则分析了棕榈纤维加筋石英砂剪切强度随纤维配比的变化规律,通过对比素砂和加筋砂在剪切过程中的体积应变及孔隙得出了棕榈纤维对石英砂力学性能的增强作用。结果表明:纤维加筋会增强石英砂在伸长破坏中的应力应变强度,对石英砂峰值应力和残余应力提升效果最佳的纤维掺量和长度为0.9%和12 mm;棕榈纤维加筋石英砂的初始弹性模量和峰值割线模量均随有效围压的增大而增大,整体刚度与有效围压呈正相关关系;纤维对石英砂剪切强度的增强效果只能在低围压状态时显现;在石英砂中添加棕榈纤维减小了石英砂的临界孔隙比及剪胀性。研究结果有助于促进纤维加筋砂的工程应用并提供相应理论参考。In order to explore the enhancement effect of palm fiber on the mechanical property of quartz sand,the reduced triaxial extension test was carried out to test the shear property of palm fiber reinforced quartz sand under saturated condition.The stress-strain curves,initial elastic modulus and secant modulus of saturated quartz sand reinforced with different fiber lengths and contents were calculated.The varying law of the shear strength of palm fiber reinforced quartz sand with the fiber content was analyzed based on the Mohr-Coulomb criterion.Furthermore,the strengthening effect of palm fiber on the mechanical properties of quartz sand was obtained through comparing the volume strain and porosity of contrast plain sand and reinforced sand during shear process.The results show as followed.Palm fibers can enhance the stress-strain strength of quartz sand during tensile failure,while the optimal fiber content and length for improving the peak stress and residual stress of quartz sand are 0.9%and 12 mm.The initial elastic modulus and peak secant modulus of palm fiber reinforced quartz sand increase with the rise of effective confining pressure,and the overall stiffness is positively correlated with the effective confining pressure.The strengthening effect of palm fibers on the shear strength of quartz sand only appears in the low confining pressure state.The critical porosity and shear dilating of quartz sand are reduced by the addition of palm fibers.The research results are helpful to promote the applications of palm fiber reinforced sand and provide the corresponding theoretical basis.

关 键 词：棕榈纤维 加筋砂 减载伸长 剪切强度 孔隙比 

分 类 号：TU411[建筑科学—岩土工程] S156.99[建筑科学—土工工程]