引江济淮工程不同水泥掺量下膨胀土改性试验研究

Experiment on Expansive Soil Modification with Different Cement Contents in the Diversion Project from the Yangtze River to the Huaihe River

选取引江济淮工程代表性膨胀土进行了不同掺量水泥和养护龄期的对比试验。研究结果表明:水泥掺量为2%,养护时间1 d时改性膨胀土的样品自由膨胀率从51%大幅度降低至42.3%,降低了约18%;水泥浆掺量达到7%后,改性膨胀土的自由膨胀率陡降至26.9%-32.1%,已经属于非膨胀土;加入水泥后改性土的抗压强度呈缓慢增长态势,但是3 d养护周期以内掺量为2%、4%和5%条件下改性膨胀土的抗压强度值呈现降低了8%~12%;当水泥掺量达到3%后,改性膨胀土的粘聚力和内摩擦角均大幅增加,掺量3%~5%范围内增速最大,当水泥掺量达到7%养护7 d后,粘聚力增长了194.5%,内摩擦角增加了72.2%。

In this paper,the representative expansive soils were selected for the comparative test,by different cement content and curing age,in the diversion project from the Yangtze River to the Huaihe River.The results show that when the cement content is 2%and the curing time is 1 day,the sample free swelling ratio of cement-treated expansive soil is greatly reduced from 51%to 42.3%,which is about 18%.When the cement slurry content reaches 7%,free swelling ratio of cement-treated expansive soil drops to 26.9%~32.1%,which is already a non expansive soil.The strength increases slowly after treating,but the content is 2%,4%and 5%in the 3 days curing cycle,the strength decreased by 8%~12%;when the cement content reaches 3%,the cohesion and internal friction angle of the cement-treated expansive soil increase significantly,and the increase rate is the largest in the range of 3%~5%,and the cement content reaches 7%for 7 days,the cohesion increases by 194.5%,and the internal friction angle increases by 72.2%.