Verification of pull‑out resistance of anchors in soil/rock formations using empirical and finite element methods

摘要

This paper introduces an investigation using 3-D finite element method (FEM) and empirical methods for prediction of pull-out resistance (skin friction) of ground anchors installed in soil, and soft rock formations are presented. Four full-scale ground anchor tests installed into different soils and rock types namely, clay, silty sand, and sandstone, were carried out. The tests were performed up to twice of working loads or failure loads so that the ultimate skin friction resistance for each soil/rock strata under the pull-out loads was estimated. Furthermore, an extensive site investigation campaign was performed to predict the in situ soil/rock characteristics. Field test setup and installation method of the full-scale ground anchors were presented in details. FEM (Plaxis 3D subroutine) was used to verify the results of the pull-out field tests. Besides, the measurements of the field tests were compared with the values of unit skin friction resistance given by the well-known codes of practice (AASHTO, and BS 8081) for design of ground anchorage. It was found that the proposed 3-D FEM and the adopted constitutive models provided good agreement with the field test results.