隔断层厚度对盐渍土路基边坡稳定性的影响研究

我国现阶段的公路建设里程不断增长,相较于常规平原地区,高寒区公路建设要克服盐渍土路基带来的各类不良影响。高寒地区常见的盐渍土体中富含盐分,容易出现盐分迁移和结晶的现象,从而导致路基边坡稳定状态发生变化。现有工程施工方案中常设置隔断层,但目前关于隔断层厚度对路基边坡稳定性产生影响方面的研究仍较为薄弱。通过设计多种厚度的级配砾石隔断层,利用有限元模拟软件,可模拟并对比各厚度级配砾石隔断层对路基边坡稳定性的影响结果。研究成果显示,相较于无级配砾石隔断层的盐渍土路基,设置隔断层的路基边坡稳定性有所降低,并随着隔断层厚度的增加下降;当级配砾石隔断层的厚度设置超过30cm后,模拟路基边坡的危险滑动面位置触及坡脚隔断层处,随后其厚度继续变大并不会对危险滑动面产生明显影响。

Effect of Crumb Rubber Content on Low Temperature Performance of Rubber Modified Asphalt

The low temperature performances of rubber modified asphalt and crumb rubber composite SBS modified asphalt with the different contents are analyzed through the bending beam rheometer (BBR) test. The results show that with the increase of crumb rubber content, the stiffness modulus of rubber modified asphalt gradually decreases, the creep rate gradually increases, the asphalt gradually softens, the low temperature deformation and the stress dissipation capacity gradually improve, and the low temperature performance gradually improves. As the content reaches 18%, its low-temperature performance grade (PG) can be upgraded by one level compared with the base asphalt. For crumb rubber composite SBS modified asphalt, with the addition of SBS, the stiffness modulus of the rubber modified asphalt slightly increases while the creep rate also increases. It is explained that the addition of SBS makes the rubber modified asphalt rubber hardened, and also its low temperature deformation and stress dissipation capacity are improved. As the rubber powder content increases from 5% to 18%, its low temperature stiffness modulus decreases by about 50%.