Study On Monitoring System For High-speed Railway Roadbed Subsidence Displacement

This subject is a practical project from a Dalian high-speed railway company. Its aim is to implement remote and real-time monitoring for weak roadbed subsidence displacement. This weak roadbed is made of underground old coal mining area. If the weak roadbed collapses widely, it will threat seriously train and human. Therefore, the application of this monitoring system is very important for assuring the safety of train.Based on characteristics of the practical project, this subject proposes a new non-contact method which can measure the subsidence displacement automatically and real-timely. It also finishes an applicable and reliable remote monitoring system.The monitoring system is mainly made of two monitoring terminals and a set of monitoring center. Monitoring terminal consists of a laser distance sensor, some special shaped targets, a step motor, a singlechip controlling system and a GPRS wireless data transport module and so on. Monitoring center is composed of a special-purpose server, the data collecting and dealing module, database and the data display module and so on.The monitoring terminal contains a set of measure device and some targets. The measure device is fixed on a strong place out of the weak roadbed and named measuring point. Targets are fixed in the range of weak roadbed and called measured point. Laser distance sensor, as one part of the measure device, measures the distance between measuring point and measured point. Targets changes roadbed subsidence displacement to the distance variation got by laser sensor. Singlechip control system collects the variable distance and changes it to the roadbed subsidence. To assure the reliability of this system, we set 10 targets in every weak roadbed. SCM control system controls a step motor to make laser distance sensor aim at every target accurately. The monitoring terminal collects roadbed subsidence displacement in a real time, and sends this information to monitoring center wirelessly by GPRS data transport module. The function of monitoring center is receiving data, extracting, saving and displaying them. If there is something dangerous, it will give an alarm automatically at once. The system can realize the real-time transferring of data to Internet, which provides the supervisors with spot data every moment and everywhere as long as they can access to the Internet.