摘要
套管式TDR水分传感器可以实现土体水分空间分布的连续变化观测。为明确套管式TDR水分传感器的测试准确性、稳定性及平面侧向感应范围,设计方形平面边长依次为100~600 mm、高度为400 mm的砂箱模型,进行10%目标质量含水率标准砂试样的标定试验。分析表明:砂箱边壁位于传感器平面侧向感应范围以外,质量含水率测试误差为正态分布随机误差,且置信水平为0.95的误差分布区间仅为(-0.41%,+0.41%),满足土工试验规范要求平行测定差值不大于1.0%的规定,测量精度达到了传感器标称±2%等级标准;针对沿深度变化的砂土含水率,TDR测试值通过了显著性水平α=0.05的多样本变异系数齐性检验,具有良好的稳定性;砂箱模型边壁侵入传感器平面有效感应范围将导致TDR测试值显著偏小,所用套管式TDR水分传感器的侧向感应范围约为300 mm边长的截面。
The TDR access-tube moisture sensor can measure the spatial distribution of soil water continuously. In order to definite the accuracy,stability and lateral inducting scope of access-tube sensors,a set of sandbox models of square planar were designed that the length of the side range from 100 mm to 600 mm and the height is 400 mm.The calibration experiments for standard sand samples were carried out that the target water content was 10%.Analysis results show that when the side wall of the sandbox is located outside the inducting scope of TDR, the test error of water content is random error following normal distribution.The error interval is only (-0.41%,+0.41%)with 0.95 confidence level,thus meeting specification requirement of soil test that the difference of parallel determination is less than 1 .0%.The measuring accuracy reaches the nominal precision level of ±2%. According to the variation of water content with depth,TDR values pass the testing for homogeneity of coefficients of variation at the 0.05 significance level,which proved TDR has satisfactory stability.The invasion of side wall into inducting scope leads to significantly decreased TDR testing values;therefore,the inducting scope of TDR ac-cess-tube moisture sensor is a cross-sectional area that the side length is about 300 mm.
出处
《铁道科学与工程学报》
CAS
CSCD
北大核心
2016年第5期827-835,共9页
Journal of Railway Science and Engineering
基金
国家重点基础研究发展计划(973计划)项目(2013CB036204)
关键词
套管式TDR
侧向感应范围
含水率
标定试验
砂箱模型
TDR access-tube
lateral inducting scope
water content
calibration experiment
sandbox model
