Deep large underground structure construction method

The invention discloses a deep large underground structure construction method. The method comprises the steps that a first tunnel extending in the first direction is constructed through an ultra-deep vertical shaft; a plurality of second tunnels which extend in the second direction and are arranged in parallel at intervals are constructed from the first tunnel through the special-shaped shield tunneling machine, and a plurality of independent primary supports are formed in the second tunnels; and the stratum and underground water between the adjacent second tunnels are stabilized through the pressure-controllable stratum reinforcing and freezing technology, then segments on the adjacent sides of the primary support are dismantled step by step, a connecting structure is constructed in an expanding excavation mode, meanwhile, an internal secondary structure is constructed, and the primary support and the secondary structure are stressed cooperatively to jointly form the deep large underground structure. Accord