纯粉煤灰路堤填筑特性试验研究

Experimental study on the properties of pure flyash embankment

由于燃煤品种、燃烧方式和程度、回收工艺不同，粉煤灰的化学成分、粒度组成、压缩特性、抗剪强度等性质存在较大差异。针对荆襄高速公路K151＋040-K161＋420段应用的粉煤灰，对其化学成分、粒度组成、最佳含水量、内摩擦角、粘聚力和压缩系数等指标进行了试验研究。结果表明：SiO2和Al2O3的含量超过75％，颗粒主要分布在0．01～0．125mm之间，细颗粒中含碳量较少，重型击实最佳含水量为30．7％，含水量在较宽的范围内变化时均能接近最大密实度，压缩系数α1-2约为0．18MPa^-1，级配良好，压缩适中，适用填筑路堤。

On account of difference in original coal kinds, combusting ways and degree and recovering technics, the chemical component, granulometric compositlon,compressibility and shearing strength of flyash will be difference much. Aiming at the flyash used in K151 ＋ 040 - K161 ＋ 420 section of Xiaoxiang expressway, the chemical component, granulometric composition, optimum water content, internal frictional angle, cohesive strength and compression coefficient are studied by experiments. It shows that the content of SiO2 ＆ Al2O3 exceeds 75% ,the sizes of particles smainly distribute at 0. 01 mm to 0. 125 mm,carbon content in fine particles is less, optimum water content with heavy compacting method is 30. 7%, maximum density can be obtainned with an wide variation water content range,compression coefficient is about 0. 18 MPa^-1. The graduation is well, compressibility is moderate. It is fit for filling embankment.