Research, Practice And Benefit Analysis Of Construction Technology On Large Diameter And Variable Cross-section Pile Foundation And The Elevated Pile Caps In The Large Deep Water Bridge

Engineering project for deepwater bridge foundation is one of the key points of bridge construction, and the quality of its construction scheme is closely related to the project progress, quality, safety and efficiency. How to solve the special characteristics of a single project, the technical strength and equipment level of the enterprise itself, the technical research and innovation, the establishment of the implementation of technical feasible, economic and reasonable construction technology program to ensure the construction period, to achieve the established quality and safety objectives to maximize corporate profits, has a very practical significance.The present research aimed to resolve the following problems based on the deepwater bridge and high pile cap stage implementation problems encountered: water flow needs, complex geology, inland waterway, immediately upstream of operation frequent car ferry crossing, and large diameter variable cross-section pile foundation, flood and tide influence. First of all, considering the project hydrology, geology, climate, surrounding facilities and the influence of special projects and constraints, we determine to use the two stage of implementation of water steel platform on trestle bridge + 60 t gantry crane with the general construction technology of hoisting the case of innovation through comparative analysis. Second, we carefully considered various loads the whole process encountered, especially the steel platform construction of trestle bridge steel accidental load, and we replace the conventional steel deck of steel bridge deck by trestle bridge innovative precast reinforced concrete slab, to ensure the trestle bridge platform security, economy and applicability. Third, by using the large diameter steel tube construction technology, large diameter pile with variable sections of variable cross-section hole the technology of large diameter, variable cross-section pile mud preparation technology, mud circulating system and hole cleaning technology, processing and assembling and transporting steel cage of different diameter steel cage connection, the technology of underwater concrete filling and construction technology research, we ensured the project completed successfully. Fourth, through comparative analysis and design scheme, we optimized the technical proposal of the high pile cap adopts the single wall steel suspension box cover, and the steel hanging box plate mold block design into sections bridge other sub-segment of the construction template to be universal.After the implementation of the project, the overall technical scheme guarantees the construction, passing straight ship and adjacent to the ferry vehicle ferry and people crossing the safe, smooth and efficient completion of the Da’ao bridge deepwater large diameter variable section pile foundation and the construction of high pile cap; all steel trestle bridge platform has achieved its goals after 300 t loaded steel platform ship accident impact nondestructive main structure; deepwater large diameter variable section pile foundation construction smoothly and reach the predetermined schedule, quality and safety, the full bridge of large diameter pile foundation pile with variable cross section are continuous and complete without defects, pile bottom and base rock closely, sediment; construction of high pile cap and seen the ebb and the flood peak test, safe; because of the owners of funds and other reasons that delay the whole project 3 years, in the absence of delay compensation, we successfully completed the whole project eventually with a net profit rate of 6.5%.