Method for keeping roundness of pressure steel pipe in concrete backfilling process

Abstract

The invention discloses a method for keeping the roundness of a pressure steel pipe in a concrete backfilling process, and belongs to the technical field of pressure steel pipe construction. The method comprises the following steps: before concrete backfilling, a keeping device is put into the pressure steel pipe, keeping hydraulic cylinders on two sides are driven to synchronously contract by a PLC (Programmable Logic Controller) control system, and moving end plates on two sides are driven to approach by the keeping hydraulic cylinders, the movable end plates push a supporting plate to expand outwards through a diagonal draw bar, so that the supporting plate is in contact with the inner wall of the pressure pipeline; and the PLC control system control the keeping hydraulic cylinders to contract to drive the supporting plate to apply pressure to the inner wall of the pressure pipeline, the pressure borne by the outer wall of the pressure pipeline is balanced, the roundness of the pressure pipeline is guaranteed, deformation of the pressure pipeline is effectively avoided, and the pressure applying amplitude of the supporting plate to the pressure pipeline is controlled by sensing the change of the oil pressure of the inner cavity of a movable supporting hydraulic cylinder, the arrangement of a stroke sensor on the keeping device is reduced, so that the keeping device is simpler in structure and higher in use stability.

Description

technical field [0001] The invention relates to the technical field of penstock steel construction, in particular to a method for maintaining the roundness of penstock steel pipes during concrete backfilling. Background technique [0002] Penstocks are used more and more in hydropower stations, especially the water delivery system of pumped storage power stations, which are often lined with penstocks in large quantities due to the influence of geological conditions. In the process of water conservancy construction, the pressure steel pipe is rolled by steel plate. During the transportation, the inner support and the outer reinforcement ring are used to reinforce it to prevent deformation; in the subsequent construction process of the pressure steel pipe outsourcing concrete pouring construction, the internal support is also required. Continuous support is used to prevent the deformation of the penstock during the outsourcing concrete pouring process; therefore, the internal ...

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Problems solved by technology

[0003] There are two traditional forms of internal support, one is welding, the internal support used in this method does not have the function of rounding, it can only play a role of reinforcement after rounding, and increase welding, after use according to the specification Requires the workload of cutting, grinding weld scars, and trimming of support pipes. In addition, if you do not pay attention to grinding, it will also damage the base metal and reduce the thickness. If it exceeds 2mm, welding repairs are required, which seriously affects the quality of the penstock. The way of screw rod, this method uses the screw rod to adjust the circle and play the role of support and reinforcement. The design and processing of the screw rod requires high precision. During use, when encountering thicker steel plates, it is laborious to manually adjust the screw rod The rounding effect is poor, and in the process of concrete backfilling of penstocks except for the horizontal section, it is often carried out in sections. The existing support method is very troublesome to install and disassemble when backfilling in sections, which affects the efficiency of concrete backfilling construction

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