Evaluation of MEMS-Based In-Place Inclinometers in Cold Regions.

摘要

Inclinometer probes are used to measure ground movement. While an industry standard, this technology has drawbacks, including costly trips for manual measurements, operator error, and limited measurements due to casing deformation. Relatively new MEMS-based in-place inclinometers (M-IPIs) consist of MEMS accelerometer segments separated variously by flexible joints or field-connection systems, and encased in watertight housing. M-IPIs provide nearly continuous ground movement measurements, accommodate greater ground movement due to their flexibility, and may contain temperature sensors. Two M-IPIs from different manufacturers were evaluated for three different vertical and horizontal applications in Interior Alaska. Each M-IPI was evaluated for ease of installation and subsequent retrieval, durability, and functionality in frozen ground. Measurements from both devices compared well to those from the inclinometer probe, indicating that these devices are suitable for use in cold regions. Field experience indicates that the installation procedure for each instrument is better undertaken at above freezing temperatures, due to required manual dexterity and the temperature requirements of casing adhesive. If used to measure both ground movement and temperature in frozen ground, the M-IPI temperature sensors should be calibrated. We recommend replacing cold-affected plastic components between installations to avoid unwanted breakage during reinstallation.