Differential-Pressure Type Precision Measuring System of High-Speed Railway Substructure Settlement

A differential-pressure type settlement measuring method based on pressure transmitter was proposed for precision measurement of high-speed railway substructure settlement and deformation. First, the settlement measuring principle was introduced based on Euler differential equation of static fluid. Then, the measurement system error caused by temperature change was solved by differential-pressure treatment and temperature correction of fluid density. Typical technical parameters of the pressure sensor, such as the thermal sensor drift and sensor range, were analyzed; and a high-precision integrated system for automatic settlement measurement, namely HSMS-1, was designed and used in practice to measure the settlement of a high-speed railway bridge. The results showed that the measured values by HSMS-1 were consistent with those by an electronic level in the temperature range of -18 to 42 ℃, and the maximum error was only 0.44 mm. With a measurement range of 300 mm, the accuracy class of system could reach 0.2. Therefore, this system is applicable to long-term automatic monitoring of high-speed railway substructure settlement in complex natural environments.