A contactless positioning system for monitoring discontinuities in three dimensions with geological and geotechnical applications.

In this paper, a contactless positioning system is presented which has been designed to monitor the kinematic behavior of mechanical discontinuities in three dimensions. The positioning system comprises a neodymium magnet, fixed on one side of a discontinuity, and a magnetoresistive sensing array, fixed on the opposing side. Each of the anisotropic magnetoresistive sensors in the sensing array records the magnetic field along three orthogonal directions. The positioning system intrinsically generates compact data packages which are transmitted effectively using a range of standard wireless telecommunication technologies. These data are then modeled using a global least squares fitting procedure in which the adjustable parameters are represented by the position and orientation of the neodymium magnet. The instrumental resolution of the positioning system can be tuned depending on the strength of the magnetic field generated by the neodymium magnet and the distance between the neodymium magnet and the magnetoresistive sensing array. For a typical installation, the displacement resolution is shown to be circa 10 μm while the rotation resolution is circa 0.1°. The first permanently deployed positioning system was established in June 2016 to monitor the behavior of an N-S trending fault located at the contact between the eastern Alps and the Vienna Basin. The robust design of the positioning system is demonstrated by the fact that no interruptions in the broadcasted data streams have occurred since its installation. It has a range of potential applications in many areas of basic and applied research including geology, geotechnical engineering, and structural health monitoring.

[1]  Beatriz García,et al.  A multicriteria system for the monitoring and alert of the cracks found in Santos Morcillo Lake, Central Spain , 2014 .

[2]  R. Couture,et al.  Understanding the kinematic behavior of the active Gascons rockslide from in-situ and satellite monitoring data , 2015 .

[3]  F. Qin,et al.  Ferromagnetic microwires enabled multifunctional composite materials , 2013 .

[4]  Robert Mellors,et al.  Anthropogenic subsidence in the Mexicali Valley, Baja California, Mexico, and slip on the Saltillo fault , 2010 .

[5]  Valentina Zhukova,et al.  Novel magnetic microwires-embedded composites for structural health monitoring applications , 2010 .

[6]  J. Stemberk,et al.  Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria) , 2015 .

[7]  Tao Zhang,et al.  A Wireless Monitoring System for Cracks on the Surface of Reactor Containment Buildings , 2016, Sensors.

[8]  Robert J. Mellors,et al.  Land subsidence in the Cerro Prieto Geothermal Field, Baja California, Mexico, from 1994 to 2005 , 2011 .

[9]  Peng Lin,et al.  A Flexible Network Structure for Temperature Monitoring of a Super High Arch Dam , 2012, Int. J. Distributed Sens. Networks.

[10]  M. Derron,et al.  Statistical analysis of seasonal displacements at the Nordnes rockslide, northern Norway , 2010 .

[11]  M. Wieland,et al.  Long-term dam safety monitoring of Punt dal Gall arch dam in Switzerland , 2012 .

[12]  Jerome P. Lynch,et al.  A summary review of wireless sensors and sensor networks for structural health monitoring , 2006 .

[13]  J. Balek,et al.  Monitoring Giant Landslide Detachment Planes in the Era of Big Data Analytics , 2017 .

[14]  F. Nava,et al.  Fault Slip, Seismicity, and Deformation in Mexicali Valley, Baja California, Mexico, after the M 7.1 1999 Hector Mine Earthquake , 2002 .

[15]  Adam Chrzanowski.  Modern Surveying Techniques for Mining and Civil Engineering , 1993 .

[16]  J. López-Gutiérrez,et al.  New insights on speleoseismology: The geothermal gradient and heat flow values in caves for the study of active faults , 2017 .

[17]  Thomas B. Afeni,et al.  Review of surface mine slope monitoring techniques , 2010 .

[19]  R. Simpson,et al.  Using Surface Creep Rate to Infer Fraction Locked for Sections of the San Andreas Fault System in Northern California from Alignment Array and GPS Data , 2014 .

[20]  M. Ruymbeke,et al.  Observation and interpretation of fault activity in the Rochefort cave (Belgium) , 2012 .

[21]  N. Derby,et al.  Cylindrical magnets and ideal solenoids , 2009, 0909.3880.

[22]  Riccardo Salvini,et al.  Application of an integrated geotechnical and topographic monitoring system in the Lorano marble quarry (Apuan Alps, Italy) , 2015 .

[23]  Laura Asensio,et al.  A synthetic model of cracking in Santos Morcillo Lake, central Spain , 2012 .

[24]  Long-term behavior and safety assessment of Sance Rockfill Dam , 2011 .

[25]  Emidio DiGiampaolo,et al.  Wireless Passive RFID Crack Width Sensor for Structural Health Monitoring , 2015, IEEE Sensors Journal.

[26]  V. Holý,et al.  The instrumental resolution of a moire extensometer in light of its recent automatisation. , 2016, Measurement : journal of the International Measurement Confederation.

[27]  Richard A. Schultz,et al.  Terminology for structural discontinuities , 2008 .

[28]  M. J. Van De Wiel,et al.  Calculating flux to predict future cave radon concentrations. , 2016, Journal of environmental radioactivity.

[29]  R. Bilham.  Coseismic Strain and the Transition to Surface Afterslip Recorded by Creepmeters near the 2004 Parkfield Epicenter , 2005 .