贵州地区炭质页岩填料路用性能与路基结构设计研究

Research on Performance and Subgrade Structure Design of Carbonaceous Shale Filler in Guizhou Area

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 the filling of carbon shale for expressways in Guizhou Province, the engineering properties of carbonaceous shale filler are tested, and based on the dry and wet effect, the characteristics CBR and resilience modulus of carbon shale filler under different dry and wet conditions are analyzed. It is found that the long-term nature of carbonaceous shale is affected by wet and dry effect and weathering effect. Its CBR decreases gradually with the increase of immersion time of sample, and 7 days after immersion in water was stable, it is 35.7% lower than that of water immersion 4 days. Meanwhile the CBR and resilient modulus decrease with the increase of dry wet cycles, and the stable value after the 5 cycle is decreased by 48.7% and 21 % respectively compared with the initial state. It is suggested that the CBR value of the 5 wet dry cycles is used as the long-term strength index of the carbonaceous shale filler, and the test shows that the stability CBR value could meet the requirements of the embankment filling intensity. At the same time, some typical treatment measures and subgrade structures are designed, which can provide reference for similar project.