Inclinodeformeter pressure measurements in creeping landslides: analytical solutions and field applications

The paper derives analytical solutions for deformation of viscoelastic pipe in elastic soil under far-field principal stress increments. These solutions are validated in laboratory tests and numerical analysis and provide the basis for back-calculation of earth pressure increments from measured changes in shape of an inclinometer pipe cross-section using inclinodeformeter (IDM) technology. The procedure has been applied to back-calculating earth pressure changes and soil stiffness in three creeping landslides in Switzerland, which are similar in size but have a range of different boundary conditions and displacement rate fields. In these applications, pressure increments of less than 1 kPa could be reliably back-calculated allowing for identification of compression and extension zones, as well as yielding and failure of soil in the landslides under study, confirming the previously developed models of the landslide mechanisms and suggesting that IDM pressure measurements could serve as a reliable tool for analysis and monitoring of creeping landslides.