According to the design drawings, combined with the actual geological and topographical conditions, three main construction methods are generally adopted for the construction of the underwater pier, namely, the method of building island cofferdam with backfill soil, the method of erecting cap steel sheet pile cofferdam, and the method of building island by filling in steel sheet pile cofferdam.

The method of cap steel sheet pile cofferdam is generally applicable to the construction of the pier in water with a wide river surface and deep water. The main construction contents include: first build a temporary trestle to approach the pier position, and then set up the water construction platform. The drilling rig is installed on the water construction platform for bored pile construction. After the bored pile construction is completed, steel sheet pile cofferdams are inserted around the bearing platform (steel sheet pile cofferdam can also be constructed at the same time with the water construction platform). The size of steel sheet pile cofferdam is generally (a + 3) MX (B + 3) M, The bottom of the pile cap shall be sealed with concrete under the bottom of the bearing platform. The steel sheet pile, steel purlin, and steel pipe (or steel) support shall be constructed while pumping water. The pile cap shall be constructed, and the steel sheet pile cofferdam shall be removed finally. Larsen III or Larsen IV steel plates are generally used for steel sheet pile cofferdams.