用微波炉快速测定黄土含水率最佳烘干时间的确定

Determination of the Best Drying Time for Rapid Detecting the Loess Moisture Content by Microwave Oven

以往现场测定黄土含水率的方法主要有烘干法、酒精灼烧发、比重计法、碳酸钙气压法等。微波炉的出现给含水率测定带来新的途径。微波炉烘干是否破坏了有机质,测试数据是否有效,最佳烘干时间是多少成为不可逾越的问题。笔者以延安地区黄土及红黏土为研究对象,采用微波炉烘干和常规实验室烘箱烘干方法,对比了不同烘干时间的土样含水率,确定了土样含水率达到稳定时的烘干时间。结果表明:微波炉烘干达到10min后,其结果与烘箱烘干法一致,方法有效;微波炉设定高火力,延安马兰黄土(Qp3)烘干时间为7min,离石黄土(Qp2)烘干时间为8min,对新近系N2b-j组红粘土烘干时间为10min;与烘箱烘干法相比,波炉烘干法可现场测试,省去了送样和和长时间烘烤时间,显著提高了工作效率,可作为工程施工及地质调查现场快速测定含水率的方法。

The drying method is a commonly used method in the determination of loess moisture content.The laboratory uses oven drying method.At the engineering site,the microwave ovens are commonly used for drying in order to save time.There is no uniform standard for the best time to dry in a microwave oven.In this paper,the drying of loess and red clay in Yan'an area has been carried out by microwave oven.The moisture content of soil samples with different drying time has been compared,and then the drying time for the moisture content of soil samples reached stability has been determined.The results show that,when the microwave oven is set to high firepower,the drying time is 7 minutes for Yan'an Q3 loess,8 minutes for Q2 loess,and 10 minutes for red clay in N2b-j group.This result can be used as a reference for rapid determination of moisture content of loess and red clay at the site of engineering construction and geological survey.