Sealed grouting front end device and grouting construction method

The invention discloses a sealed grouting front end device and a grouting construction method. The device comprises a protective casing, a junction pipe and a grouting connection pipe. The first end of the protective casing is detachably connected with a conical head; the pipe wall of the junction pipe is provided with a grouting hole, the protective casing covers the grouting hole by sleeving theouter side of the junction pipe, and the junction pipe and the protective casing can be relatively movably arranged and are provided with an anti-drop structure; and the first end of the grouting connection pipe is detachably connected to the end, far away from the conical head, of the junction pipe, and the first end of the protective casing sleeves the outer side of the first end of the grouting connection pipe and is provided with a sealing ring. When the grouting front end device carries out drilling in the soil body, the device is in a closed state, due to the fact that the sealing ringis additionally arranged,