Improvement of a slope disaster warning system for practical use

Abstract

This paper reports on the development of an advanced slope disaster monitoring system for practical use. In 2010, we developed a distributed wireless sensor network and installed it on a slope along an expressway to detect and monitor water behavior and deformations in the slope due to heavy rainfalls at an early stage. In this previous research, three major issues remained unresolved: poor wireless communication data collection rate, sensing performance, and monitoring system. To resolve these issues, in 2013, improved monitoring systems with wireless mesh network functions were set up on slopes along six expressways managed by the West Nippon Expressway Company in Japan. Consequently, we confirmed that data were constantly being sent to the data server every ten minutes, even at single-hop wireless communication distances up to 400 m. Improvements in the sensor nodes by adding strain gauge sensors and contact input and output devices made them useful not only for monitoring slope failure but also for maintenance of the slope by the ground anchor method and evaluation of the drainage effect of the embankment. (However, improvements in the electric field strength and addition of a retry function resulted in a decline in battery life.) The improved monitoring system allows road managers to view the data at each site at any time. Further, the data can also be downloaded from the webserver on the Internet.