新型二氧化硅复合材料在路基固化土中的力学性能测试研究

Testing and research on the mechanical properties of new silica composites in subgrade solidified soil

以纳米SiO_(2)(nano-SiO_(2))石灰综合固化的黄土为研究对象,通过标准击实试验、无侧限抗压强度试验、回弹模量试验、CBR承载力试验,研究了纳米SiO_(2)掺量和养护龄期对固化黄土最大干密度、最优含水率、静回弹模量及CBR等物理力学性能的影响,通过扫描电镜测试了固化黄土的微细观结构。结果表明:纳米SiO_(2)石灰综合固化黄土随着纳米SiO_(2)掺量的增加最优含水率逐渐增大,最大干密度减小,固化黄土的无侧限抗压强度、回弹模量和CBR随纳米SiO_(2)掺量的增加而增大,随养护龄期的延长不断增长,养护前期(7~28 d)固化黄土的强度增长速度快,后期强度增长速度变慢;扫描电镜结果显示,纳米SiO_(2)的掺入改善了土颗粒的团聚方式,填塞了土颗粒间的孔隙,达到了提高黄土强度和改善稳定性的效果。

Taking the loess solidified by nano-SiO_(2) lime as the research object,the effects of nano-SiO_(2) content and curing age on the physical and mechanical properties of solidifyed loess were studied through standard compaction test,unconfined compressive strength test,resilience modulus test and CBR bearing capacity test,and the microstructure of solidified loess was tested by scanning electron microscope.The results showed that with the increase of nano-SiO_(2) lime content,the optimal moisture content gradually increased,the maximum dry density decreased,the unconfined compressive strength,resilience modulus and CBR of the solidified loess increased with the increase of nano-SiO_(2) content,and increased with the extension of the curing period,and the strength growth rate of the solidified loess in the early stage of curing(7~28 d)was fast,and the strength growth rate of the solidified loess in the later stage slowed down.The results of scanning electron microscope showed that the incorporation of Nano-SiO_(2) improved the agglomeration mode of soil particles and filled the pores between soil particles,thus improving the strength and stability of loess.