Construction method of escape ventilation shaft in shield electric power tunnel interval

The invention discloses a construction method of an escape ventilation shaft in a shield electric power tunnel interval. The construction method mainly includes the steps of (1) tunneling a shield electric power tunnel, replacing top B-type pipe pieces in prefabricated concrete pipe pieces with detachable steel pipe pieces in preset areas of an escape shaft and a ventilation shaft in the electricpower tunnel interval, and continuously tunneling without influencing construction period; (2) synchronously positioning the positions of the escape shaft and the ventilation shaft on the ground, sinking a prefabricated pipe well or a steel sleeve to a position which is about 0.3-0.5 m away from the top of the shield electric power tunnel at the positions by using an open caisson method, and synchronously adopting a point precipitation or local advanced grouting water stop structure; (3) excavating a last connecting section of the shield electric power tunnel manually, welding steel bars to the steel pipe pieces at th