Application of MEMS Gravity Sensors to Detect Underground Hazards at the Global Centre for Rail Excellence

Traditional gravity sensors are mechanical, large and expensive. Smaller sensors based on quartz spring technology have been available for many years yet they remain relatively large, high cost and insufficiently rugged for deployment in many infrastructure applications.

For gravity to move beyond existing applications, a sensor that offers high sensitivity and stability in real-world environments, has a small form factor and low power consumption, is rugged and has relatively low cost needs to be available.

This paper presents the development of a MEMS vibrating beam gravity sensor and its application in a gravity survey at the Global Centre for Railway Excellence site in Wales.

From borehole drilling, the existence of a void, probably an old coal mining, was known at 10–12m depth. Based on information from the borehole drilling potential scenarios were forward modelled to demonstrate that a micro-gravity survey could detect the void. Then a field survey was performed using SMG’s MEMS GAIA gravimeter. The paper reports the results of that survey which demonstrated the ability of this new technology to detect the void and its application to site surveys for infrastructure and construction.