Research On The Optical Measurement Technique Of The Settlement Of Subgrade Surface

Heavy-haul train leads to great damage on the subgrade and causes the settlement and deformation, which include the long-period cumulative subsidence and the elastic deformation. To monitor these aspects has a great realistic significance to the maintenance and safe operation of the existing railways.This paper designs an automatic monitoring system, using infrared LED and linear CCD for measuring the surface of subgrade settlement and the dynamic displacement of heavy haul railways. The main contents include three parts:1. For the single-point subgrade settlement's measuring apparatus, first, introduce its work principle and optical design, and then set up experiment system in the lab for verification. For multi-points measuring, design auto-scanning scheme and grouping network scheme, and discuss their application scope and key technology.2. Combined with the site condition, choose grouping network scheme for building measuring system at three critical sections along the Da-Qin railway. And then give a detailed analysis and corresponding solutions of the factors which have effect on the measurement accuracy.3. By changing the circuit and the optical design in some areas, the apparatus can also be used for measuring the dynamic displacement of the subgrade. After principle testing in the lab, this apparatus has been installed in the railway for measurement.By analyzing the data acquired from long-time monitoring, the regularity and the development trend of the subgrade can be got, which will provide scientific basis for promoting the railway transport capacity and designing new heavy haul railways.