Shield launching construction method for water-rich soft soil liquefied stratum

The invention discloses a shield launching construction method for a water-rich soft soil liquefied stratum. The method comprises the following steps that S1, end starting reinforcement is conducted; s2, sealing installation of the tunnel portal; s3, a tunnel portal is chiseled away, a shield tunneling machine penetrates into the tunnel face, and a negative ring is assembled; s4, the shield tail passes through the starting hole, and synchronous grouting is started; in S1, a shield starting end adopts a thick diaphragm wall, and end reinforcement adopts horizontal grouting and horizontal freezing reinforcement; s2, tunnel portal water stop device installation, bracket installation and counter-force frame installation are included, and tunnel portal water stop device installation comprises tunnel portal embedded part arrangement and three-way sealing arrangement; the brackets are mounted on the left and right sides of the portal and are reinforced by I-shaped steel; the longitudinal axis of the shield tunneling