寒区路基冻融过程中改良盐渍土抗剪性能分析

Analysis of shear resistance of improved saline soil during freezing and thawing of subgrade in cold regions

为了探究路基水泥、粉煤灰改良盐渍土冻融过程中的抗剪性能,取冀北某公路路基土样,配置复合盐渍土,对经历不同温度节点冻融循环后的改良盐渍土进行直剪试验。结果表明:冻融过程中掺加水泥改良的盐渍土土体抗剪性能提升显著;盐渍土中掺入5%水泥+15%粉煤灰的改良后,黏聚力和内摩擦角较5%水泥改良土体均有小幅提升。双掺水泥、粉煤灰较单掺水泥有更好的改良效果。

In order to explore the shear resistance of saline soil subgrade improved by cement and fly ash during the freeze-thaw process,the composite saline soil was prepared from a subgrade soil sample of a highway in northern Hebei,and the freeze-thaw test at different temperature nodes was carried out after the improvement with different amounts of cement and fly ash,and the direct shear test was conducted after the freeze-thaw.The results show that the shear resistance of saline soil improved by adding cement during freezing and thawing is significantly improved;After the saline soil is improved by adding 5%cement+15%fly ash,the cohesion and internal friction angle are slightly improved compared with 5%cement improved soil.It is better to mix cement and fly ash at the same time than cement alone.