GTS performed additional tests this month and discovered that there may be some slight movement after all. Attached is a graph of data from one of five inclinometer wells, this one from a well located within the berm itself. If you compare the test dates, it shows both positive and negative movement, back and forth, which can be attributed to instrument inconsistency. The measuring instrument is extremely sensitive and it's not unusual to have slight inconsistencies among tests. The positive/negative differences in the early readings were averaged and the conclusion was that the slope had moved very little.
The concern now is that the three most recent tests over the last 18 months for this particular well show a possible trend (all positive, no negative data points) indicating the possibility of slope instability. The graph indicates movement of about 1/8 inch. Very small but it could indicate some instability. There is a blockage in one of the well shafts near N building about 40 feet down and Chris is trying to locate a camera this week to find out if the shaft has separated (minor inconvenience) or is sheared (major problem which could be proof of substantial earth movement). Chris has yet to plot the other three inclinometer data readings and will compare the data from those locations to see if there is a similar trend.
It may be necessary to wait another six months (we have become very accustomed to waiting) and conduct additional tests. If the readings indicate a negative direction, as in earlier tests, those results would be averaged with prior data and would again support the conclusion that the slope is stable. If future readings show a continued positive trend the conclusion may be that the slope is still moving, if ever so slightly. Further work to mitigate the problem may be necessary. The engineers are being extra cautious as no one wants to declare the problem solved and spend a lot of money fixing things up, only to discover that the slope is still unstable. At present the test results remain somewhat inconclusive and further testing may be required to increase the confidence level in the conclusions and recommendations.
