为了研究水泥粉煤灰不同掺量对超盐渍土的力学性能影响规律,分别以1%,3%,5%水泥和20%、25%、30%粉煤灰掺入宁夏平罗县姚伏镇的超盐渍土中对其进行固化,并进行7 d 和28 d 龄期的三轴 UU 试验。结果表明:7 d 龄期,相同掺量粉煤灰固化超盐渍土的摩擦角和粘聚力随水泥掺量的增加呈近似线性增加;28 d 龄期,相同掺量粉煤灰固化超盐渍土的摩擦角随水泥掺量的增加趋势呈先慢后快;粉煤灰掺量为20%时,摩擦角随龄期的增加而增加,粉煤灰掺量为25%和30%时,摩擦角随龄期的增加而减小;固化超盐渍土轴向应变较小时,水泥和粉煤灰对主应力差的影响较小,随着轴向应变的增大,水泥粉煤灰固化超盐渍土的作用逐渐增强。建议利用水泥粉煤灰固化超盐渍土时,当固化盐渍土地基三向约束较强时,可以采用1%~3%水泥和20%~25%粉煤灰固化超盐渍土,反之,采用5%水泥和30%粉煤灰或更高掺量的水泥粉煤灰固化超盐渍土。
In order to study the influence of different content of cement and fly ash on mechanical properties of hypersaline soil, the hypersaline soil from Yaofu, Pingluo county of Ningxia, was mixed with 1% , 3% and 5% cement and 20% , 25% and 30% fly ash for solidification, respec-tively, and the soil of 7-day and 28-day age were investigated by triaxial UU test. The results show that for the soil of 7-day age, when the dosage of fly ash is the same, the friction angle and the co-hesion linearly increases with the content of cement; that for the soil of 28-day age, the friction an-gel increases slowly first, and later it increases fast with the cement. Comparing the overweight sa-line soil of 28-day age and 7-day age, several interesting conclusions are obtained. When the dosage of fly ash is 20% , the friction angle increases with the age; when the dosage of fly ash is 25% or 30% , the friction angle decreases with the age. When the axial strain is small, the dosage of cement and fly ash has little effect on the main strain. With the increase of axial strain, the solidification of cement and fly ash of hypersaline soil is obvious. Some advices are also proposed for the design and construction of solidification of hypersaline soil with cement and fly ash. When solidified saline soil suffers from strong constraints, 1% - 3% cement and 20% - 25% of fly ash stabilized saline soil can be used, otherwise 5% cement and 30% fly ash or higher dosage of cement fly ash solidified saline soil must be used.