水泥粉煤灰搅拌饱和黄土强度影响因素试验研究

摘要

Most of sections along Lanzhou to Zhongchuan Airport Railway Engineering fall into the saturated foundation with low bearing capacity, high compressibility and are reinforced by composite cement-soil mixed pile foundations. The strength performances of cement-fly-ash mixed saturated loess are tested and studied. Under such conditions with different cement and fly ash ( hereinafter referred to as the"two ash") admixture ratio, different cement strength grade, different age, the variation of unconfined compressive strength of cement soil is analyzed. The test results show that the unconfined compressive strength increases with the increasing of two ash admixture, age, the unconfined compressive strength of two ash admixture for cement soil 20% is 1. 42 times of two ash admixture 15%, and is 1. 9 times of the two ash admixture 12%;when the total admixture of two ash is unchanged, with fly ash in total of two ash ratio of 1/5 ,1/4 , 1/3 , cement soil strength decreases slightly; the unconfined compressive strength of cement soil increases obviously with the increasing of strength grade of cement, and the strength of cement soil increases dramatically with the increasing of the amount of cement and fly ash.%兰州至中川机场铁路工程沿线大多地段属于饱和黄土地基，承载力低，压缩性大，采取水泥土搅拌桩复合地基进行加固。对水泥粉煤灰搅拌饱和黄土强度特性进行试验研究。在不同的水泥和粉煤灰(以下简称“二灰”)掺和比、不同的龄期、不同的水泥强度等级下，分析水泥土无侧限抗压强度的变化规律。试验结果表明：水泥土无侧限抗压强度随二灰掺量、龄期的增加而增大，二灰掺量为20%的水泥土无侧限抗压强度是二灰掺量为15%的1.42倍，是二灰掺量12%的1.9倍；当二灰总掺入量不变，粉煤灰掺入量占二灰比例为1/5、1/4、1/3时，水泥土强度略有降低；水泥土无侧限抗压强度随水泥强度等级的提高而显著增大，且随二灰掺量的增加，水泥土强度增加幅度增大。