Inclinometer ASTM D6230

Standard Practices for Monitoring Earth or Structural Movement Using Inclinometers

 

An inclinometer is a deformation monitoring system, which uses a grooved pipe or casing with internal longitudinal grooves aligned with the anticipated direction of movement, installed in either a soil/rock mass or a geotechnical structural element. The inclinometer casing can be surveyed with a single traversing probe or with an array of in-place inclinometer (IPI) gauges connected to a data logger. The measurement and calculation of deformation normal to the axis of the inclinometer casing is done by passing a probe along the length of this pipe or placement of a sensor array, guided by the internal grooves. The probe or sensor array measures the inclination of the pipe, usually in two orthogonal directions 90° apart (X- and Y-direction) with respect to the axis of the casing (Z-direction, usually the line of gravity). Measurements are converted to distances using trigonometric functions. Successive surveys compared with an initial survey give differences in position and indicate deformation normal to the axis of the inclinometer casing. In most cases the inclinometer casing is installed in a near-vertical hole, and the measurements indicate subsurface horizontal deformation. In some cases, the inclinometer casing is installed horizontally, and the measurements indicate vertical deformation.

Inclinometers are also called slope inclinometers or slope indicators. Typical applications include measuring the rate and direction of landslide movement and locating the zone of shearing, monitoring the magnitude and rate of horizontal movements for embankments and excavations, monitoring the settlement and lateral spread beneath tanks and embankments, and monitoring the deflection of bulkheads, piles or structural walls.