Inlinometer data

[fardilha]

I have to frequently, manage with inclinometer data, as a result of that several doubts come to me:

1 - In many ocasions ( particulary when the displacements are less then 1 or 2 mm ), the " outputs " ( for the 2 usualy ortogonal components A and B ), don´t show any particular evolution. Some times the horizontal displacement increase other times is the opposite.

2- Are there any literature related with this subject available.

3- What are the major causes for data field instabilization? Presence of water, bad casing assembly, etc.

4- Programs, that could generate a 3 D model, from de a X/Y chart.

5 - As anyone, manage with SISGEO, inclinometer equipment.

Thanks

rui.fardilha@clix.pt

 

[bmike]

My guess on your first question is that the readings are not being precisely taken at the same point in the casing each time. If there is any curvature at all at your reading depths, you will get a slightly different slope each time you take a reading. Since you are essentially measuring the slope of the casing at discrete points, this may manifest itself as apparent small forward and backward movements.

 

[TAC]

We've had some fits with our slope incinometer before. bmike could be right. Make sure that you have the cable marks lined up in the same place for every reading. Conasistency is important.

Another possibility is settlement of granular backfill around the casing. I don't know how long your casing has been in place or what you used for backfill around the casing, but we suspect that an initial shift in our data from a recent job may have been due to loose granular backfill settling around the casing. Movements were very small < 1-2 mm but were noticible.

Another possibility is noise in the instrument. Periodically our data shifts one way or the other along the whole length of the casing and seems to be from noise. Try checking out the incremental displacement as opposed to the cumulative displacement. You should see the data jingle (technical term) back and forth on either side of the zero displacment line (with the exception of sections where you actually are getting movement). If more of the data points happen to fall to one side more than the other, then cumulatively you will see a slight movement in that direction. Sometimes the data points will fall more to the other side and you will see a slight shift back the other way.