珠江地区深层水泥拌合体强度试验研究

珠江地区某海上工程下覆深厚的淤泥层,采用深层水泥搅拌法对地基进行处理,由于处理深度大,地区经验少,须对水泥拌合体的强度进行研究。因此,原位取样,在室内展开了水泥拌合体强度的试验研究,通过掺入8%,10%,12%,14%,16%和18%的水泥,水灰比分别为0.9,1.1和1.3,对水泥拌合土各个龄期下的强度进行分析,结论显示即使在水灰比0.9,水泥掺入量18%的情况下,水泥拌合土90 d龄期的强度仍小于1.0 MPa,强度偏低。在加入粉煤灰和木镁外加剂后,水泥拌合土的强度得以提高,可达1.4 MPa。所以,在实际工程应用中必须要添加外加剂,以增加活性。

Experimental research on strength of cement deep mixing soil in Zhujiang area

There covers very thick soft clay in Zhujiang area. For a project of this area, the cement deep mixing method is used to improve the clayey ground. However, the soft clay is very thick and it is lack of experience, so we need to study the strength of cement mixing soil: after taking soil sample in situ, we start our test on the strength of cement mixing soil. Taking the cement amounts as 8%, 10%, 12%,14%,16% and 18% respectively, and water cement ratios as 0.9, 1.1 and 1.3, we analyze the strength of cement mixing soil at different ages. The results show that even under the condition of 18% cement amount and 0.9 water cement ratio, the strength of cement mixing soil at 90 d age is less than 1.0 MPa, which is lower than normal. After mixing fly ash and admixture of UNF-5, the strength of cement mixing soil is increased to 1.4 MPa.Therefore, admixtures must be mixed into the cement mixing soil to increase the active strength.