Construction method of extra-long tunnel ventilation inclined shaft zero-interval over-crossing intersection main hole

The invention provides a construction method of an extra-long tunnel ventilation inclined shaft zero-distance over-crossing intersection main tunnel, which comprises the following steps: (1) air duct zero-distance over-crossing main tunnel design, (2) advance excavation and support of a main tunnel influence section, (3) periphery grouting reinforcement and backfill, (4) air duct micro-step over-crossing construction, (5) intersection main tunnel portal construction, and (6) trapezoidal small pilot tunnel method top-picking construction. (7) supporting an upper step of the main hole; (8) removing a temporary shed frame support; and (9) normally constructing the main hole. The construction method is suitable for construction projects of crossing the main hole of the intersection tunnel on the connection air duct of the long and large tunnel ventilation inclined shaft of the expressway under various complex geological conditions. According to the construction method, the construction difficulty of overcrossing