Abstract: An excavation bucket incorporating an impact actuator assembly is described herein. The excavation bucket includes a bucket body, a movable head, a movable floor portion mounted to the movable head and an impact actuator provided between and mounted to the bucket body and the movable head. The movable head is longitudinally movable in the bucket body. The movable head is provided with tools, such as teeth, to penetrate hard soils. These tools are slidably mounted in the movable head to reach a retracted position when they are pushed against hard soil. When the impact actuator is activated, the longitudinal impacts generated by the impact actuator drive the tools into the hard soil if the tools are in their retracted positions. However, if the impact actuator is activated while the tools are not in their retracted position, the longitudinal impacts will cause the repetitive longitudinal movements of the movable head and thus of the movable floor with respect to the bucket body.