Method for dismantling compressed concrete beams in deep-foundation-pit unsupported enclosure system

The invention relates to a method for dismantling compressed concrete beams in a deep-foundation-pit unsupported enclosure system. The method is characterized by comprising the following steps that (1) according to the section of one compressed concrete beam in the deep-foundation-pit unsupported enclosure system, a counter-force support is manufactured; (2) the counter-force support is fixed to the compressed concrete beam through a horizontal shear resistance bolt; (3) the other pairs of counter-force supports are mounted a certain distance away from the position where the counter-force support is mounted by repeatedly carrying out the step (2); (4) horizontally-arranged jacks with the equal number are arranged between every two counter-force supports; (5) jacking force is applied to thejacks, the jacking force value is matched with the pressure borne by the compressed concrete beam, at the moment, a pressureless beam is formed, cutting is implemented on the pressureless beam, and the cutting face is parall