千枚岩用于高速公路路基填料的适用性研究

Study on Application of Phyllite as Highway Subgrade Filler

对千枚岩的物理力学特性、水稳定性以及其CBR与压实度的关系进行了研究,结合现场千枚岩路基填料碾压特性,提出了千枚岩作为高速公路路基填料适用层位及压实要求。结果表明:随着千枚岩风化程度加重,其颗粒密度和块体密度减小,含水率、吸水率和孔隙率逐渐增加,点荷载强度减小;随着干湿循环作用次数增加,千枚岩试样崩解量递增、耐崩解性指数减小;与干燥千枚岩相比,饱水千枚岩强度显著降低,降低幅度达39%~64%;适当提高压实标准,弱风化千枚岩可用作路基填料,中风化千枚岩可用于路堤和下路床,强风化千枚岩只适用于下路堤;采用3%~4%水泥改良中风化、强风化千枚岩可适用于路基各结构层。

The physical and mechanical properties and water stability and the relationship between CBR and compaction degree of phyllite are studied. Combined with on-site phyllite rolling characteristics, the applicable layer and compaction requirements of phyllite as a highway subgrade filler are proposed. The results show that with the increase of weathering degree of phyllite, the grain density and bulk density decrease, and the water content, water absorption and porosity increase gradually, and the loading strength decreases; with the increase times of drying and watering cycle action, the amount of phyllite sample disintegration increases, the disintegration resistance index decreases ; Compared with the dry phyllite, the strength of the saturated phyllite is obviously reduced, with the reduction range of 39 % -64 % ; Appropriately improving the compaction standard, weakly weathered phyllite can be used as subgrade filler, intermediary weathered phyllite can be used as embankment and down roadbed. Strongly weathered phyllite is only applicable to the down embankment; 3 % -4 % cement modified intermediary weathered and strongly weathered phyllite is applicable to all the structural layers of subgrade.