EVALUATION OF CRANE PAD PERFORMANCE ON PARTIALLY IMPROVED GROUND ADJACENT TO A SEAWALL

摘要

A Demag CC1800 crawler crane was partially erected on crane mats adjacent to a seawall when settlementsrnnear a corner of the crane mat area were observed to be slightly larger than previously assessed. A groundrnimprovement program including installation of dry soil cement mix (DSM) piers was implemented tornimprove soil bearing capacity. Due to near-surface obstructions, only 75 percent of the DSM piers wererninstalled to the design depth. Because of the partial installation of the DSM piers, an evaluation of the cranernpad stability and the effect of the crane loading on the stability of an adjacent 10-ft high concrete seawall,rnwhich was believed to have limited (if any) reserve capacity, was required. A two-dimensional finiternelement model was developed to evaluate the responses of the partially improved ground and the sea wallrnto the loads imposed by the crane. Geotechnical site investigation and laboratory testing programs werernperformed to better define the subsurface conditions near the area where settlements occurred and to providernthe required mechanical parameters for the soil constitutive model. Analysis results indicate that total andrndifferential settlements of the crane pad and the increase in load on the seawall were tolerable providedrnlimited excavation and replacement of weak dredged soils outside the DSM area would be implemented.