TEST METHOD OF HOLLOW DRIVEN PILE WITH A WIDENED BASE Russian patent published in 2020 - IPC E02D33/00 

FIELD: construction.

SUBSTANCE: invention relates to the field of construction, in particular to methods of static testing of pile foundations from driven (pressed) hollow piles with open ends mainly in weak wet and waterlogged soils underlaid by bearing layer of soil with required physical and mechanical characteristics. Method for driving a driving hollow pile with a closed lower end includes a dipping of a pile, stepwise loading of the pile with a static pressing load, forming a broadened base, determination of bearing capacity of pile on side surface and determination of total bearing capacity of pile at end and side surface. Hollow pile is lowered with the punching puncher at the specified depth and then its stepped loading is performed with a static pressing load till conditional stabilization and the bearing capacity of the pile F_d is determined, which is equal to the sum of bearing capacities of the pile at the end F_dR and side surface F_df. Then pile is unloaded and casing inventory pipe-rod with detachable tip is inserted into its cavity and into cavity of puncher, puncher is immersed to the depth of formation of the widened base with formation of a well-cavity under the pile, after which the pipe-rod is removed and a well reamer is introduced into the internal cavity of the pile, with the help of which the soil under the pile end is cut or compacted. Extractor is withdrawn from pile cavity and stepped loading of pile is performed again and its carrying capacity is determined on side surface F_df; then pile is unloaded, expanding shoe-expander is installed in cavity of puncher, and forming a broadened base by layer-by-layer filling of the hard soil material to the well-cavity above the shoe-expander to a height to the lower butt end of the pile and its sealing by the end face of the detachable ferrule of the pipe-rod to the lower butt end of the pile. Pile is produced to failure state, its stepwise loading is performed again and the bearing capacity of pile F'_d is determined equal to the sum of its carrying capacities along end face in broadened base F'_dR and side surface F_df, then, calculating difference between each total value F_d and F'_d and value of bearing capacity F_df on side surface of pile, determining separately bearing capacity of pile on end face in compacted soil F_dR and in widened base F'_dR.

EFFECT: technical result consists in improvement of accuracy of determination of load-carrying capacity of piles due to exclusion of formation of pilot well, provision of more complete information on bearing capacity of pile, as well as expansion of field of use on ground conditions.

4 cl, 4 dwg