Development and application of a wireless MEMS-based borehole inclinometer for automated measurement of ground movement

Abstract

Generally, the excavation work performed to lay the foundation and create the underground space of structures causes deformation of the surrounding ground. Such deformations could threaten the lives of residents and the safety of structures. Consequently, borehole inclinometers have been used to monitor these deformations. The typically used underground inclinometers have the disadvantages of lack of durability, difficulties in measuring local inclination because of a relatively long inclinometer, loss of data due to long connecting cables, and electromagnetic interference. To overcome these disadvantages, in the present study, a wireless MEMS-based borehole inclinometer system composed of a tilt sensor module, processor module, and slave and master nodes was developed. The developed borehole inclinometer system was configured by a two tier sensor to minimize its diameter. Its field applicability was improved by minimizing the cables between the sensor and the server through the application of a long range wireless module between the computer server and master node and a short range wireless communication between the master node and sensor node. A field test was conducted to verify the applicability and data reliability of the developed wireless MEMS-based borehole inclinometer. The reliability of the proposed system has been proved by the analysis of data collected for two months at two different construction sites.