External expansion type large-diameter cylinder suction pile provided with explosive enlargement device

The invention relates to foundation steel pipe piles, in particular to an external expansion type large-diameter cylinder suction pile provided with an explosive enlargement device and used for oceaneering. The cylinder suction pile comprises a main cylinder (1), and a top plate (2) covers the top face of the main cylinder (1). An annular explosive box (3) is fixedly connected to the inner wall of the main cylinder (1) and surrounds the inner wall of the main cylinder by one circle. The explosive box (3) and the inner wall of the main cylinder (1) form a sealed explosive enlargement bin. A box body of the explosive box (3) is composed of a stacking structure (4) and a steel plate (5). Explosives (6) are placed in the explosive box (3). The wall thickness of the main cylinder (1) is smaller than the thickness of the steel plate (5) of the box body of the explosive box (3). A detonation device is installed on the box body of the explosive box (3). The compression resistance, uplift resistance and lateral comprehensive bearing resistance of the pile are effectively improved due to the fact that the explosive enlargement device is installed in or connected with the cylinder pile and one or more external expansion type lantern-shaped local enlargement parts are formed through explosive enlargement.