Construction method for special-shaped steel cofferdam

Abstract

The invention discloses a construction method for a special-shaped steel cofferdam, which comprises the following steps of: measurement and positioning, erection of a steel pipe pile bracket, installation of a steel cofferdam laying fixation device, assembly, heightening and laying of the steel cofferdam, deviation correction and positioning of the steel cofferdam, bottom seal in a compartment and the steel cofferdam, disassembly of the steel cofferdam steel pipe pile bracket, erection of a pile foundation borehole platform, positioning and installation of a steel casing (24), final bottom seal, drilling and pile formation, disassembly of the pile foundation borehole platform, water pumping from the steel cofferdam, chiseling of pile head concrete, construction of a bearing platform and apier body, cutting and reclamation of the steel cofferdam, and clearing of the river, wherein the assembly process of the steel cofferdam comprises assembly of a first section, namely a bottom section (6), and the shape of the assembled special-shaped bottom section can be tightly combined with the river. The method is suitable for foundation construction of a deepwater bridge pier without a covering layer and with complex terrain on the riverbed, saves the work amount of blasting and chiseling on the bottom rock layer of the riverbed, is easy for next bottom sealing construction, and can save the bottom sealing concrete number and the work amount of processing the steel cofferdam.

Description

technical field [0001] The invention mainly relates to a cofferdam construction method applied to a bridge pier foundation on a river bed, in particular to a special-shaped steel cofferdam construction method applied to a bridge pier foundation with complex river bed topography. Background technique [0002] Shaoguan Zhenjiang Bridge (center mileage DK179+951.508) is a key control project of the ZQ-3 bid of the newly-built Ganshao Railway Project. It is located in Shaoguan City, Guangdong Province and crosses the Zhenjiang River in Shaoguan City. The navigable level is VII, and the design navigable clear height 4.5m, side height 2.8m, navigable clear width 66m, upper bottom width 61m, highest navigable water level 57.88m, full bridge length 270.165m, span arrangement of (44+72+44)m prestressed concrete continuous beam and 3 -32m simply supported T-beam. The bridge has 5 piers and 2 bridges in total. Piers 1# to 4# are all located in the channel of the Zhenjiang River. They ...

AI Technical Summary

Problems solved by technology

The bridge has 5 piers and 2 bridges in total. Piers 1# to 4# are all located in the channel of the Zhenjiang River. They all use Φ1.5m bored pile group foundations. The caps are all located in deep water. The main piers 1# and 2# are located in the main channel. (the 1# pier is located at the turning of the river), the river is deep (the deepest reaches 11m), the water is rapid, the slope of the riverbed is large (the slope within the scope of foundation construction is large, and the height difference is 4.5m), there are many boulders and eroded river channels, no Overburden layer, the river bed is a hard limestone rock layer with a bearing capacity of up to 1200Kpa, and the cap is partially embedded in the river bed rock near the Ganzhou platform, which brings great difficulties to the construction of pile foundations and caps. Therefore, the ordinary steel cofferdam scheme The terrain cannot achieve the purpose of construction

Images