Lumped parameter modelling of single-tendon ground anchorage systems

Research into the static and dynamic performance of ground anchorage systems has been in progress at Aberdeen University since the early 1980s. This programme has involved computer and laboratory modelling in conjunction with measurements on active construction sites. Latterly the work has concentrated on investigating resin bonded rock bolt anchorages and has led to the development of a new method for the non-destructive testing of anchorages. As part of the programme research was undertaken to assess how changes in the material properties of the resin grout and the presence of debonding/grout defects influenced anchorage dynamic response. To that end a lumped parameter model has been developed to simulate anchorage dynamic response. The acceleration response was examined at a number of points in the anchorage system i.e. at the protruding length as well as at the anchorage head, along the free length, along the fixed length and even within the rock mass itself. A parametric study was then undertaken with regard to changes of material properties of the resin and the introduction of defects such as debonding. The following paper presents results which have arisen to date from the analysis undertaken on this preliminary numerical model.