oa Multiple Receiver Loop SNMR Surveys Applied to Geo-Technical and Civil Engineering Problems

While surface nuclear magnetic resonance (SNMR) has primarily been applied to hydrology problems -- particularity in 1D -- there exist myriad other applications for this technology. there is a large number of problems where directly detecting and/or imaging water is of primary concern. A few examples include geo-technical and civil engineering problems such as locating voids in roads that are potential sinkholes, monitoring or exploring for leaky dams, landslide hazard assessment and permafrost monitoring. Many of these problems are Inherently 3D in nature. Although the latest generation of multi-channel SNMR instruments has opened the door to 3D surveys, little work has gone into this area. Questions such as feasibility and survey design require 3D modeling capabilities.<br>We have developed a general forward modeling algorithm that supports arbitrarily shaped loops, with surface topography, as well as decoupled transmitter and receiver loops. the algorithm makes all calculations in the frequency domain and models the entire dataset. Three dimensional electrical conductivity and water distributions are supported and the loops may be embedded in or at the surface of the earth.<br>using our new algorithm, we investigate the feasibility of several novel SNMR applications. We consider the case of a leaky levee or dam structure with Internal erosion and piping. We seek to determine whether SNMR loops can be used to monitor the presence and progression of the erosion. We consider loops both on on the surface and embedded within the structure. We also examine the problem of using SNMR to image water filled voids that can turn into sinkholes.