I found that most of the research on density-driven porous flow are based on numerical simulation and lab-scale monitoring. I wonder if there are any good equipment/technique can be used for monitoring the density driven unstable flow in a field site (for example, the coastal area).
I'm considering about using geotechnical tools, like TDR and Electrical Resistivity Tomography. But had no experience with using these and not sure if they are able to be applied for this problem.
Any thoughts and suggestions on this issue? Thx!
We have used TDR and Electrical Resistivity Tomography for monitoring the movement of water within a landslide. TDR is great because it gives you a precise volumetric water content but only for a small point (or rather a small space the size of a tennis ball). Electrical Resistivity Tomography on the other hand does not actually give you information on the exact water content but rather of the relative status (wet, wetter, rather dry) for a long profile.
You might want to check out page 130 (and the part around it) in my dissertation:
Book Landslide analysis and early warning - Local and regional ca...
Hi Benni Thiebes ,
Thanks a lot for your comments and I've just read your dissertation. I'm also thinking about coupling TDR with ERT. Actually my field site is a bit more complex. Since it's a coastal marsh land and largely affected by tides, which means the groundwater level in the marsh varies. On the other hand, we want to focus more on characterizing the pore-water salinity than the water content. We are thinking about ERT to imaging the resistivity change of the soil profile but then realized that resistivity change can be resulted by both water level change (water content) and pore-water salinity, which makes it difficult to figure out the salinity distribution. Coupling ERT with TDR may work as TDR gives water content information (less affected by salinity?) but still not sure if it's possible to interpret salinity distribution through ERT results.
Thanks!
Yue
Self potential is a good for fluid flow especially if you have a conductivity model from ERT to constrain results.
Yue Liu , yes, in my case salinity was not an issue but will greatly affect your ERT results. If you have questions on TDR probes, you could contact Rolf Becker
Hi Yue,
Perhaps a spatial TDR or a frequency dependent dielectric approach might help. We have used the dielectric methods to determine the state variables (moisture content, porosity etc.) of soils along side concentration of suspended solids in aq. solutions in the recent past. You have rightly pointed that pore fluid salinity impacts the TDR traces, but this can be taken care of either by modifying the sensor or by applying a semi-empirical approach.
Prof. Alexander Scheuermann at UQ would be the one nearby to have an expert opinion.
Kind regards,
Partha
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