Study On Method And System For Automatic Measuring And Monitoring All Parameters Of Subgrade Settlement

ABSTRACT:With the rapid development of high-speed railway and heavy haul railway in China, subgrade settlement measurement and settlement control have attracted much attention in recent years. There are some disadvantages of existing methods, such as incomprehensive parameters in measurements, problems of establishing surveying datum points for subgrade subsidence monitoring, and difficulty in getting the whole situation of subgrade subsidence due to the relative independence measuring points. Furthermore, most traditional methods are done manually, which are time-consuming, hard sledding and less efficient.This thesis focuses on the studies of real-time automatic measuring methods of multi-parameters and comprehensive subgrade settlement. In our research, a new real-time automatic system was realized to meet the requirement of rapid development of railway in China, which can measure many kinds of settlements accurately.The main innovations of this thesis consist of:1) A novel method to measure the surface settlement is proposed and a device has been developed. The device mainly contains a point light source and a point-position measurement device that uses a linear CCD to detect the position change of the point light's image. Any position change of the point light source can be measured and the settlement for one point can be obtained remotely. The multi-point settlements can be obtained by using a series of such devices. Some methods such as self-calibration of the magnification, automatic background subtractions etc. have been adopted to enhance the stability, adaptability and accuracy of the measurement system.2) A new method to automatically measure subgrade layered settlement and lateral displacement and another new method to automatically measure transverse section settlement are proposed in this paper, both of which are based on inclinometers. There are one or two step motors used to make the vertical or horizontal inclinometer move along the PVC pipe in the subgrade, and in this way, the scanning and measuring the subgrade settlement can be realized. The measuring principle, system configuration and design of software and hardware were given in the paper, and the stability and reliability of the system were verified by the laboratory experiments and field experiments. 3) A remote automatic monitoring system for subgrade settlement is researched and developed, which includes surface settlement measurement subsystem, layered settlement and lateral displacement measurement subsystem, transverse section settlement measurement subsystem and wireless data transformation subsystem. The long-term, comprehensive, remote automatic monitoring of subgrade settlement has been realized. By field experiments the feasibility and practicality of this system is validated.