The invention provides a construction method for an underground
pipe rack to pass through a river. The method comprises the following steps that paying off is conducted, and the
pipe rack river passing section excavation line position is determined; beside the safety distance, a diversion channel connecting the upstream part and the downstream part of a
pipe rack river passing section excavation line is excavated; a first
cofferdam and a second
cofferdam capable of intercepting
water flow are arranged on the two sides of the pipe rack river passing section excavation line correspondingly, after the area between the first
cofferdam and the second cofferdam is subjected to water lowering, excavation is conducted from one end of the pipe rack river passing section excavation line, the designed depth is excavated, a first foundation pit support is arranged on the side wall of the foundation pit, excavation continues till the final depth required by the pipe rack river passing section is reached, and a second foundation pit support is arranged on the side wall of the part, below the first foundation support, of the foundation pit; according to the
normal sequence, the pipe rack river passing section is constructed, and after construction is finished, the pipe rack river passing section is subjected to waterproof treatment; and the foundation pit is subjected to backfill, the river is changed into an old way, and forward pipe rack construction continues. The technology is simple, excavation is conducted through a technology method, safety and guarantee are provided, cost is low, and the construction method is economical and reasonable.