Influence of Different Initial Conditions on Test Accuracy of Sand Moisture Content
Hu Jianwei1，Xie Yongjiang1,2,3，Weng Zhicai1,2,3，Liu Zike1,2,3，Wang Yuehua1,2,3，He Long1,2,3
（1.China Academy of Railway Science，Beijing 100081,China；2.Railway Engineering Research Institute，Beijing 100081,China；3.State Key Laboratory for Track Technology of High-Speed Railway, China Academy of Railway Science，Beijing 100081,China）
Abstract : Microwave method was used to test the Influence factors on testing precision of water content of sand,which were about the installation angle of the water content tester from 10° to 90°, the clay content of sand from 0.5% to 3.5%, fineness modulus from 2.2 to 3.2, and sand in the loosely packed state and close packing state under two different sparse densities. The results show that: when the installation angle of the water content measuring instrument is from 30° to 60°, the measured values are relatively concentrated, the error is small, the testing precision is high, and the optimal installation angle is 40° to 50°; the fluctuation of sand clay content has little influence on the precision of water content test, and the test results are all within the error limit of 0.3%; when the sand fineness modulus fluctuates within the range of 2.4 to 2.8, the influence of the test precision on the sand moisture content is basically negligible; treatment under different sand moisture content, the higher the initial moisture content, the greater influence of the sand sparse density on the testing precision. Therefore, for the microwave moisture analyzer, the sand that is consistent with the actual conditions should be used for calibration before the analyzer is used. In particular, the baseline calibration of the sand fineness and sparse density state at the site should be performed.
