Measuring Six-Degree-of-Freedom Movements of Buried Objects in Soil Using a Magnetometer

Abstract Measuring the six-degree-of-freedom movement of objects in soil can provide valuable information about geotechnical performance. Existing technology for monitoring six-degree-of-freedom movements can be cumbersome because it typically relies on a combination of multiple devices that each measure one or two degrees of freedom. A magnetometer is an innovative piece of technology to measure the entire six-degree-of-freedom movement of an object in soil in real time. The equipment consists of a source that generates an electromagnetic field and one or more sensors that can detect their location and orientation versus time based on the characteristics they sense about this field. A commercially available magnetometer with a maximum distance of 1.5 m between the sensor and source has been used to conduct a variety of laboratory tests on scaled models of offshore anchors that move through soil when loaded. These tests demonstrate the versatility and potential of using magnetometers to monitor the performance of foundations, retention systems, pipelines, and slopes.