Analysis of pull-out capacity of plate anchor using upper bound limit method

Based on the upper bound theorem of limit analysis, admissible velocity field of strip anchor is constructed by using a combination of several rotational block sets. Upper bound solutions of pull-out capacities of deep and shallow strip anchors in undrained clay are analyzed. Pull-out capacity and failure surface characteristics under different embedment inclinations and depths are studied. The results are compared with results of existing methods. It is shown that the bearing capacity of deep strip anchor is independent of the incline angle of anchor embedment and the roughness of anchor surface. The failure surface radius of deep strip anchor under completely smooth condition is half of the radius under completely rough. The failure surface of shallow strip anchor enlarges rapidly with embedment ratio increasing; and the pull-out capacity of shallow strip anchor also increases with the increasing of embedment ratio. Comparison of the upper bound solutions with the existing solutions shows good agreement. Failure surface derived from rotational block set is explicit. It can be a reference for the practical design.