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针对贵州地区高速公路炭质页岩路基填筑问题,开展了炭质页岩填料的路用工程性质试验,分析了不同干湿循环条件下炭质页岩填料加州承载比CBR及回弹模量变化特征,发现:炭质页岩填料长期强度受干湿效应与风化作用衰减显著,其CBR值随试样浸水时间增加逐渐降低,浸水7d后才渐趋稳定,比浸水4d时下降35.7%;其CBR值与回弹模量随着干湿循环次数增加均出现衰减,5次循环后的稳定值较干湿循环前分别下降了48.7%和21.0%。建议采用5次干湿循环后CBR值作为炭质页岩填料的长期强度指标。试验表明,该类填料的长期稳定CBR值满足下路堤填料强度要求。同时文中提出了贵州地区高速公路炭质页岩路基典型路段的处治措施及路基结构型式,可为类似工程提供参考。
In order to solve the problem of carbonaceous shale embankment construction in expressways in Guizhou Province, the road engineering properties of carbonaceous shale fillers were tested. The CBR and CBR of carbonaceous shale fillers under different dry and wet cycles were analyzed. The results showed that the long - term strength of carbonaceous shale filler was greatly attenuated by wet - dry effect and weathering. The CBR value of the carbonaceous shale filler decreased gradually with the immersion time of the sample, stabilized gradually after 7 days of immersion, and decreased by 35.7% than that of the 4th day. The values of CBR and the modulus of elasticity decreased with the increase of the numbers of wet and dry cycles. The values of stability after 5 cycles decreased by 48.7% and 21.0% respectively than those before drying and wetting cycles. It is recommended that the CBR value be used as a long-term strength indicator for carbonaceous shale packings after five wet-dry cycles. Tests show that the long-term stability of this type of filler CBR value to meet the embankment packing strength requirements. At the same time, the paper puts forward the treatment measures and subgrade structure of typical sections of carbonaceous shale embankment in Guizhou area, which can provide references for similar projects.