Hard plastic clay geological drilling pile and cofferdam cross rapid construction method

The invention discloses a hard plastic clay geological drilling pile and cofferdam cross rapid construction method. The method comprises the steps that a main trestle, a branch trestle, a bailey beam and a drilling platform are installed; constructing a drilled pile with a steel casing; hole guiding and grooving are conducted, and a pile casing connecting system is installed between the bored piles; a cofferdam assembling platform and a heightening steel casing are installed, the cofferdam assembling platform is connected with the steel casing, and the installed cofferdam section is connected with the heightening steel casing; installing a lifting and lowering system, installing a cofferdam inner support, completing a cofferdam water tightness test, and lowering the cofferdam through the lifting and lowering system. According to the cross rapid construction method, even though the construction procedures are various, cross optimization can be achieved, rapid construction is achieved, and the construction peri