Hydraulic Jacking Protection Of Railway Upper Span Structure

With the development of railway construction, a considerable part of our country’s existing railways have undergone electrification and the operation of double-deck container trains requires sufficient operating clearance. At the same time, the transformation of the longitudinal section of individual sections of the railway also makes many upper spans of the existing railways. The structure has the problem of insufficient headroom. The wide application of high platforms in EMU stations has also reduced the clearance between passenger flyovers, freight flyovers, pipelines, etc. that originally crossed the platforms, and the railway. The platform space layout appears to be suppressed, and the landscape is not coordinated. It is also necessary to improve the station lines. The height of the upper span structure. Therefore, carrying out the clearance reconstruction of the upper span structure is a problem to be solved in the existing railway reconstruction.

The commonly used methods for the reconstruction of the upper span structure of the existing railway include dismantling reconstruction, framing reconstruction, and reduction of line mark jacking reconstruction, each of which has its own characteristics and application conditions. Demolition and reconstruction is the removal and reconstruction of the original upper span structure and abutment. The demolition process has a greater impact on railway transportation. Fractional reconstruction involves uninterrupting road traffic on the upper-span structure and dividing the road into left and right sections for reconstruction. It is suitable for the situation where the road is relatively wide and does not allow interruption, and is generally used for highway structures. For the railway line under the upper-span structure is a slope top or flat slope line, the method of reducing the line elevation can be adopted under the premise of not affecting the train operation due to the descending slope. However, some lines have restrictions on the slope, and too long downhill will cause excessive investment costs, so it can only be used after comparing with the above method. The jack-up transformation is to use the original upper-span structure by cutting, lifting, extending, increasing the height of the pier cap or pier column and other technical measures to increase the headroom of the upper-span structure. This method has the characteristics of low investment and small impact on the surrounding environment, railway and highway transportation.

When the upper-span structure is lifted, work is done strictly in accordance with relevant regulations. If the upper span structure is an important traffic road, speed limit or traffic control is required during construction; protective signs should be set at the construction site of the hydraulic lifting device, and reflective signs and light signs should be displayed at night; personnel should be sent to protect the construction site. For railway vehicles, the following should be done: ① When scaffolding is erected near the piers on both sides of the existing railway line, steel pipe scaffolding should be used when constructing the girder, and the scaffolding should be connected to the existing piers and abutments. A dense mesh net should also be hung on the side of the railway, so that tools and materials do not intrude into the boundary. ②When using the train's running clearance to perform beam welding and wet concrete connection operations, set up protection. Stop welding operations before the train arrives to prevent sparks from falling and causing train fires. ③Across the existing railway, install the working platform at the bottom of the beam when carrying out the wet concrete connection of the beam and the construction of the transverse partition, and adopt the live protection measures when the construction is close to the existing electrified railway.

The application of the synchronous integral hydraulic jacking equipment in the clearance reconstruction of the upper span structure of the railway avoids a large amount of demolition and reconstruction works, the project cost can be reduced by about 50%, and the interference to the railway and road operations is reduced, and the construction requirements are met. , Has good social and economic benefits. In recent years, the jacking technology has been practiced in the railway electrification transformation construction, which not only reduces the transformation cost, but also saves the transformation time. Practice has shown that with the large-scale development of railway electrification reconstruction, this technology has broad application prospects.