Testing of an opto-electric landslide sensor around a toll road-bridge

This paper describes the testing of a landslide sensor around a bridge in a toll road. The landslide sensor is one system that is able to detect land displacement or structural inclination due to natural or human activities. The proposed landslide sensor consists of surface and borehole optical extensometers, electrical inclinometer, rainfall sensor, and supporting system. The supporting system consists of a microcontroller-based data acquisition system, a GSM and internet-based data transmission system, a central server, a real-time data analyzer system and a web-based interface. The landslide sensor testing was carried out by monitoring displacement and inclination of the structure around two bridge girders. The observations from the proposed optical sensor and from the conventional electronic inclinometer sensor have been recorded and compared to that from previous studies. Inclination of 0 – 0.3 degrees to east direction in the ground surface was observed as it was reported in earlier studies, and inclination to north direction of 0 – 3.9 mm was occurred in 30 m of land depth. Generally, the bridge was in a periodic north – south movement, alternately, with maximum daily movement of 14 mm, for one - month observation, caused by night and day temperature variation.