Attachment system for detachably coupling a female tube end and a male tube end to each other in order to form foundation piles, comprising: - a cylindrical sleeve hole in a tube sleeve of the female tube end ; - a corresponding cylindrical sleeve hole in a tube sleeve of the male tube end which is alignable with the sleeve hole in the female tube end when the male tube end is being fitted in the female tube end ; and - a coupling element which comprises a cylindrical base body which is fittable in these sleeve holes when the sleeve holes have been aligned with respect to each other, in order to couple the tube ends to each other; characterized in that the attachment system furthermore comprises: - a blocking pin which is provided on and extends radially with respect to the base body or one of the sleeve holes ; and - a blocking slot which is respectively provided in one of the sleeve holes or the base body and in which the blocking pin is fittable; wherein the blocking pin and the blocking slot are arranged in such a way that the coupling element is rotatable through an angle after it has been fitted in the sleeve holes , wherein the blocking pin is fitted in the blocking slot with guiding action; that at least one of the sleeve holes and the base body are provided with corresponding sleeve slots which extend at least partly axially with respect to the respective sleeve hole or the respective base body , so that these sleeve slots together form a fitting hole after the coupling element has been fitted in the sleeve holes and after the coupling element has been rotated through the angle, and that the attachment system comprises a blocking element which is fittable in this formed fitting hole in order to prevent the coupling element in the sleeve holes from rotating. - a cylindrical sleeve hole in a tube sleeve of the female tube end ; - a corresponding cylindrical sleeve hole in a tube sleeve of the male tube end which is alignable with the sleeve hole in the female tube end when the male tube end is being fitted in the female tube end ; and - a coupling element which comprises a cylindrical base body which is fittable in these sleeve holes when the sleeve holes have been aligned with respect to each other, in order to couple the tube ends to each other; characterized in that the attachment system furthermore comprises: - a blocking pin which is provided on and extends radially with respect to the base body or one of the sleeve holes ; and - a blocking slot which is respectively provided in one of the sleeve holes or the base body and in which the blocking pin is fittable; - a blocking pin which is provided on and extends radially with respect to the base body or one of the sleeve holes ; and - a blocking slot which is respectively provided in one of the sleeve holes or the base body and in which the blocking pin is fittable; wherein the blocking pin and the blocking slot are arranged in such a way that the coupling element is rotatable through an angle after it has been fitted in the sleeve holes , wherein the blocking pin is fitted in the blocking slot with guiding action; that at least one of the sleeve holes and the base body are provided with corresponding sleeve slots which extend at least partly axially with respect to the respective sleeve hole or the respective base body , so that these sleeve slots together form a fitting hole after the coupling element has been fitted in the sleeve holes and after the coupling element has been rotated through the angle, and that the attachment system comprises a blocking element which is fittable in this formed fitting hole in order to prevent the coupling element in the sleeve holes from rotating. <EOS>