Construction method for blocking deep foundation pit tube well

The invention discloses a construction method for blocking a deep foundation pit tube well, which comprises the following steps that a sleeve extends into the tube well and is pre-buried in a raft foundation, a flange is fixed at the port of the sleeve, and the underground water level is monitored through a water pumping hole; the sleeve and the flange higher than the foundation elevation are cut; a first blind plate is fixed in the sleeve, and cement phosphoric acid water glass is poured above the first blind plate; a second blind plate is fixed in the sleeve, the second blind plate is located above the cement phosphoric acid water glass, and expansive concrete is poured above the second blind plate; and the flange is fixed above the expansive concrete through a bolt. The method has the beneficial effects that the sleeve and the flange can be directly pre-buried along with raft plate construction, the flange is fixedly connected through bolts in the later period, and the leakage risk caused by non-compact po