Inclinometer Cumulative vs. Incremental Plot HELP 1

[lawcus]

Hi!
I'm a Junior Geotech with about 2 years experience, Geologist by profession; and I'm new at inclinometer monitoring (actually I'm quite new at a lot of Geotech things)
I have a question about Cumulative Displacement graphs:
If I understood the manual correctly, it adds up the displacement from the bottom of the hole upwards? Is that why it always deviates outward from the bottom (sort of like a center of rotation at the bottom?)
and what is the formula? (Baseline Reading - Current Reading? then add them all up from the bottom up)
sorry I'm really confused i actually need to know how it's plotted and calculated.

and about the Incremental Displacement, if I also understood the manual correctly:
It says Incremental displacement = Displacement at Depth - Baseline (or initial) Displacement at Depth

Am I right?

I need more guidance from the experts.

Cheers guys.

Cant upload anything, work-filtered internet.

 

[GeoPaveTraffic]

Sorry but the correct interpretation of inclinometer data is too involved for us to help you given your lack of experience. You need to talk to someone in your current firm that understands the data and can help you get started.

If you firm doesn't have someone with the correct experience, then you need to hire someone else to interpret the data for you.

Good Luck.

Mike Lambert

 

[lawcus]

Hi Mike, thanks for the advise, that's what we are currently doing. I am just part of the data retrieval, and my supervisors are doing all the analyses.

I'm actually just curious about how it's calculated. I already asked them about this one, but their explanation was not too clear. I was trying to look for other help on simpler explanation for me to understand.

Anyway, thanks for the help.

 

[Panars]

Slope Indicator gives a good explanation of the data reduction in their manual for their product. You can find a link here:
[URL unfurl="true"]http://www.slopeindicator.com/pdf/manuals/digitilt-probe.pdf[/url]
The basic process is not too difficult and can be put into a spreadsheet. However, there are multiple error correction methods that require special software.

Basically, the accelerometers in the inclinometer probe measure the tilt of the probe. From this you can calculate the deviation between the top set of wheels and the bottom set of wheels. By taking successive readings at different depths, you can calculate the profile of the casing. By comparing different sets of readings, you can calculate the movement of the casing with time.

Yes, the displacements are summed from the bottom. The assumption is that the bottom of the inclinometer casing is in stable ground. This is why it is important that the inclinometer extend deep enough to get into stable ground. If the bottom is not in stable ground, then you have to rely on accurate survey measurements of the top of the casing and back calculate the displacements. Although theoretically possible, this is very difficult to do in practice.

 

[lawcus]

Hi Panars thanks for the explanation and the link for the reference.
That explains a lot why we need to add from the bottom-up.

Cheers mate.