水泥土室内制样方法与配合比试验

水泥土室内配合比试验是深层水泥搅拌法工程应用中一项重要的前期工作。基于大量室内试验,总结提出干土制样法与湿土制样法两种不同的水泥土制样方法及其试验流程,并对其优缺点与适用性进行比较,得出以下结论:1)当以试验土样目标含水率为变量,或试验土样初始含水率大于目标含水率时,应采用干土制样法; 2)当研究在土样初始含水率下其他因素对水泥土强度的影响时,采用湿土制样法更为合适、高效。以香港冲积层黏土为研究对象,采用干土制样法分析土样含水率对水泥土无侧限抗压强度的影响。试验结果表明,在含水率40%～80%范围内,不同龄期的水泥土强度均随含水率的增加而减小,且在高含水率(大于70%)下水泥土强度随龄期增长不明显。

Sampling methods and mixing ratio experiment for cement-mixing soil

One of the important preconditions for engineering practice of deep cement mixing method is to conduct mixing ratio experiment for cement-mixing soil.Based on a large amount of laboratory experiments,we propose two different sampling methods for cement-mixing soil,i.e.,dry soil sampling method and wet soil sampling method,and corresponding test procedures,and compare the advantages,disadvantages and applicability of each method.It is concluded that:1) dry soil sampling method should be adopted for experiments in which the objective water content is variable,or smaller than the initial water content;2) wet soil sampling method is more suitable and efficient when it aims to study the effects of other parameters on the strength of cement-mixing soil with initial water content.Taking the alluvial clay from Hong Kong as a research object,we study the effect of water content on the unconfined compression strength of cement-mixing soil by mixing ratio experiment with dry soil sampling method.The results show that the strength of cement-mixing soil decreases as water content increases,and when the water content is more than 70%,the strength increases slowly with the increasing curing period.