Exact settlement measurement of substructures plays an important role in their status detection throughout all-life-cycle of high-speed railway. A Hydrostatic Pressure Difference Levelling system (HPDL) is developed based on the mechanism that pressures of any two points at different elevations in incompressible static liquid are different. The approach accounts for a hyperbolic variation in the density of the pressure transmission liquid with temperature, variation in the earth’s gravitational field and the elevation at the measurement point. High accuracy capacitive differential pressure transmitters are adopted owing to their high sensitivity, temperature-insensitive, low energy consumption, and sensing stability. The HPDL results are verified with settlement values measured by the precise level. It was demonstrated that the HPDL results correlate well with the precise level and can be considered as an effective method to measure the settlement of high-speed railway substructures.

在高速铁路的整个生命周期中，子结构的精确沉降测量在其状态检测中起着重要作用。基于不可压缩静态液体中不同高度的任意两个点的压力不同的机理，开发了一种静水压差平衡系统（HPDL）。该方法考虑了压力传递液体的密度随温度的双曲线变化，地球引力场的变化以及测量点的高度。由于具有高灵敏度，对温度不敏感，低能耗和感测稳定性，因此采用了高精度电容式差压变送器。通过精确水平测量的沉降值验证HPDL结果。