Abstract: To ensure safe and easy demolition of tanks effectively in a short length of time, while significantly enhancing safety and saving much labor, by a work vehicle 3 with an attachment 1 having cutting edges that can be freely opened and closed for boring and cutting-off operations, a bore 10a is formed in a side wall of a tank 10. A notch is made in the side wall of the tank 10, starting from the said bore 10a. The bore 10a is expanded by means of removing a cut-off piece. Before the tank 10 buckles, it is supported at the position above the bore 10a. A notch is made in the side wall of the tank 10. The bore 10a is expanded by means of removing a cut-off piece. Then, a support force against the tank 10 is adjusted by a work vehicle 4 to buckle the tank 10 while utilizing a self weight of the upper portion of the tank 10. The buckled tank 10 is handled by the work vehicles 3 and 4.

Abstract: This invention relates to a method for dismantling a cylindrical tank, comprising steps of separating the sidewall of the tank from its bottom plate, cutting the sidewall into portions along a spiral line provided on the periphery of the tank in the direction from the lower end to the upper end, and removing the portions while temporarily supporting the sidewall, said temporary supporting step being conducted so that the lower end of the removed portion is gradually lowered and the location to support the sidewall shifts as the removing step proceeds. According to this invention, one can safely and inexpensively dismantle a cylindrical tank. The method of this invention can be used even if some structures exist in the peripheral area of the cylindrical tank. Further, this method does not need a step for providing rotatably movable means or a step for rotating the upper part of the tank, resulting in a simple method that is easy to implement.