微波炉法测定遗址土含水率的可靠性研究

古代土遗址病害发展与土的含水率变化密切相关，但土遗址保护现场快速准确测定土的含水率不是一件容易的事。选择遗址土、含盐土、黄土等进行对比试验，研究分析微波炉烘干法（简称微波炉法）测遗址土含水率结果的可靠性。在测定试验土样界限含水率和易溶盐含量的基础上，对比分析微波炉法、烘箱法两种方法测定土含水率的误差来源。试验结果表明，土的塑性对微波炉法的测定有一定影响，但测定误差均在2%以内；土的含盐量影响水分的蒸发速度，不影响微波炉法的测定结果；微波法测定遗址土含水率准确，且具有快速、便捷等优势，值得在土遗址保护工程中推广使用。

Reliability research of soil moisture content measurement by microwave oven drying method for earthen monuments

The deterioration of ancient earthen monuments are highly related to the change in soil moisture content, so there is a practical need to find a way to measure accurately and easily the moisture content at heritage site.This paper reports the test results of soil water content measured by microwave drying method (MDM) compared with the standard method, the oven drying method (ODM), using soil samples including earthen monuments, saline soil and loess soil. The origin of test error by MDM is analyzed based on liquid limit test, plastic limit test, salt content test results. It has been found that the error of soil moisture content measured by MDM is increased with the increase in soil plasiticity compared with that measured by ODM; but the maximium error is restricted within 2%, satisfying the requrement of national code. Soil salt content is responsible for increasing the drying rate of the soil in MDM, but has no effect on the final masurement of soil moisture content. As a final conclusion, this research indicates that the MDM is a reliable method for soil moisture measurement in heritage conservation for its advantages of accuracy, speediness and convinence.