SOME COMMON PROBLEMS IN LOCATING SUITABLE LOCATIONS FOR INCLINOMETER PLACEMENT IN ACTIVE SLOPES: DISCUSSION AND SOME SUGGESTED SOLUTIONS

A common solution for monitoring active slopes that endanger lives and/or property is to install inclinometers. Unfortunately, it is very easy to inadvertently install inclinometers incorrectly, even for experienced practitioners. Incorrectly placed inclinometers may prove to be ineffective in addressing intended purposes such as detection of movement, characterization of movement (is the mass movement constant, accelerating or decelerating?) and characterization of the sliding surface (is the sliding planar, rotational, or complex?). Incorrect placement may also fail to forecast catastrophic failures in a warning system. In this study, a number of placement problems related to choosing a suitable location are discussed: placement such that the inclinometer misses a deeper seated sliding plane; placement such that that the inclinometer misses a shallower sliding plane; placed in an area where there is so much unexpected distortion that the sensor probe can no longer pass through the inclinometer casing; and placement in a location such that the inclinometer/casing is destroyed by catastrophic collapse or other unforeseen event.

Three possible solutions are proposed based on using information from surface mapping to characterize the subsurface. The first technique from the emerging field of optimization, seeks to optimize the spacing between inclinometers both laterally and vertically. In the second solution, an artificial neural network framework uses features mapped from the surface to characterize the subsurface. The third approach applies numerical integration at carefully selected points for subsurface characterization. These suggested solutions/approaches not only offer a general foundation for a fresh look at some commonly encountered problems in engineering geology, but also provide potential for further development.