路基土水分传感器室内标定方法与影响因素分析  

Method and effect analysis of laboratory calibration test on subgrade soil moisture sensor

作　　者：冷伍明[1,2] 涂仁盼 聂如松 梅慧浩[1,2] 范瑞祥 LENG Wuming;TU Renpan;NIE Rusong;MEI Huihao;FAN Ruixiang(School of Civil Engineering? Central South University,Changsha 410075,China;National Engineering Laboratory for High Speed Railway Construction,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]高速铁路建造技术国家工程实验室,湖南长沙410075

出　　处：《武汉大学学报（工学版）》2019年第3期231-239,共9页Engineering Journal of Wuhan University

基　　金：国家自然科学基金面上项目(编号:51878666);中国神华集团科研专项项目(编号:SHGF-14-55);中南大学研究生自主探索创新项目(编号:2017zzts156)

摘　　要：水对路基土的力学性能影响显著,但迄今对路基土含水率变化的长期跟踪测试的有效案例与研究不多.选用可靠的传感器和准确的标定是准确测试含水率变化的基础.首先介绍了EC-5土壤水分传感器测定土体含水量原理,提出了路基土水分传感器室内标定方法,然后利用某既有重载铁路路基土对EC-5土壤水分传感器进行了室内标定试验,研究了干密度和温度对EC-5土壤水分传感器测试结果的影响,建立了考虑干密度影响的含水率标定公式.结果表明,EC-5土壤水分传感器输出电压值与烘干法测定的质量含水量相关性很好,可以准确地测定路基土含水量;干密度变化对EC-5土壤水分传感器测量结果的影响较大,表现为输出电压值随着干密度的增大而增大;在0℃以上时可以不考虑外界环境温度对EC-5土壤水分传感器测量结果的影响.Water plays a significant role in the mechanical performance of subgrade soil. However, there are few successful cases or researches about long-term measurement of the variation of subgrade soil moisture content. Using reliable sensor and accurate calibration is the basis to measure moisture content accurately. In this study, the principle of measuring soil moisture content using EC-5 soil moisture sensor is introduced. The calibration method of EC-5 sensor is proposed. Laboratory calibration tests are carried out for a specific subgrade soil borrowed from an existing heavy haul railway. The effects of dry density and temperature on the measured soil moisture contents by EC-5 are considered. A calibration equation is established considering the effect of dry density. The test results show that the correlation between the exported voltages by EC-5 and the measured moisture contents by oven-drying method turn out to be very well. EC-5 is able to measure subgrade soil moisture content accurately. The effect of dry density on the measured results by EC-5 is great. The measured voltage by EC-5 increases with an increase in dry density. The effect of temperature on the measured results by EC-5 can be neglected when it was above 0 ℃.

关 键 词：土壤水分传感器 干密度 温度 体积含水量 标定试验 

分 类 号：TU411.8[建筑科学—岩土工程]