Method of constructing cofferdam after integrally lowering multiple layers of inner bracings of steel sheet pile cofferdam

Abstract

The invention discloses a method of constructing a cofferdam after integrally lowering multiple layers of inner bracings of a steel sheet pile cofferdam. The method is applied to the technical field of cofferdam construction and comprises the following steps of: heightening and constructing pile casings of the pile foundation at the bottom of a bearing platform, arranging a temporary assembly platform on the pile casings and assembling the inner bracings on the temporary assembly platform; disassembling the temporary assembly platform, arranging supporting structures at the designed elevation positions of the inner bracings on the pile casings, and lowering the inner bracings to the supporting structures; sequentially inserting steel sheet piles by using the inner bracings as inner guide till closing to form the cofferdam; and clearing sludge at the inner bottom of the cofferdam, then carrying out underwater bottom sealing by concreting, and after the strength of concrete for sealing the bottom reaches requirements, pumping water in the cofferdam dry, and constructing the bearing platform and pier bodies; and disassembling the cofferdam. The method has the beneficial effects that larger potential safety hazards caused by a conventional method of installing inner bracings and connection systems by layer-by-layer water pumping in a steel sheet pile cofferdam construction process are avoided; construction procedures are simple and easy to operate; the safety of operating personnel and the construction quality can be ensured to a greater extent; the construction period is shortened; and the construction cost is saved.

Description

technical field [0001] The invention is used in the technical field of cofferdam construction, and in particular relates to a cofferdam construction method in which multi-layer internal supports are lowered as a whole before the steel sheet pile cofferdam is lowered as a whole. Background technique [0002] The application of deepwater foundations in my country began in the 1950s. The three main stages of development and application of deepwater foundations are described from the aspects of foundation size, materials used, and structural forms, namely, pipe string foundation, caisson foundation and bored pile foundation. , composite foundations and special foundations. Steel sheet pile cofferdam is currently a very advantageous deep-water foundation cofferdam construction technology, and it is widely used in the construction of passenger dedicated lines and high-speed railway bridges. Most of its design and calculation methods are based on simplified calculations and enginee...

AI Technical Summary

Problems solved by technology

This kind of construction technology is used in the early construction of the project, and its disadvantages are that the process is cumbersome and complicated, the construction is difficult, and the construction period is long;

[0007] 2. Layered pumping is installed with internal supports, and there is a water head difference inside and outside the steel cofferdam (unbalanced water pressure inside and outside), which is prone to cofferdam deformation or even collapse accidents, and the safety factor is low;

[0008] 3. Complicated procedures and working conditions have increased the force calculation work of steel cofferdams and the input of manpower and material resources for cofferdam observations;

[0009] 4. The cumbersome technological process greatly increases the investment of construction personnel, and the construction cost is high

[0010] According to the statistical results of previous on-site construction, the construction period of a deep-water steel sheet pile cofferdam with about 2 layers of inner support can reach about 90 days. With the depth of the cofferdam and the inner support As the number of floors continues to increase, the construction difficulty and safety management risks of the internal support of the pumping and layered installation will increase, and the construction investment cost will also increase accordingly.

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