Combined water blocking structure for buried type pressure steel tube

Abstract

The invention discloses a combined water blocking structure for a buried type pressure steel tube. The combined water blocking structure comprises a pressure steel tube (2), wherein the front sectionof the pressure steel tube is inserted into a reinforced concrete tunnel (1); a group of water blocking rings (3) is arranged on the front section, inserted into the reinforced concrete tunnel, of thepressure steel tube; a group of reinforcing rings (4) is arranged on the rest of sections of the pressure steel tube; backfill concrete (5) is arranged at the peripheries of the rest of sections of the pressure steel tube; a joint of the backfill concrete and the reinforced concrete tunnel is equipped with a permanent deformation seam (9); a copper sheet water stop ring (10) is arranged in the permanent deformation seam; the reinforced concrete tunnel and the backfill concrete are positioned in a rock body (6); and seepage-proofing curtain grout (7) and inclined reinforcing grout (8) are arranged in the rock body. The structure can block inner and outer water from soaking into the periphery of the pressure steel tube very well, reduces outer water pressure, ensures safe operation, is simple and convenient in operation process, reduces operation cost, and is remarkable in water blocking effect, so that the purpose of economic rationality is achieved.

Description

technical field [0001] The invention relates to a combined water blocking structure of buried pressure steel pipes, which belongs to the technical field of metal structures of water conservancy and hydropower projects. Background technique [0002] From the reservoir, the forebay or the surge chamber to the hydro turbine of the power plant, the penstock is mostly used as the pipeline for conveying water. The penstock is usually buried in the rock mass, and concrete is filled between the penstock and the rock mass. Generally, the front end of the penstock is connected to the reinforced concrete tunnel. There is a possibility of internal water leakage at the connection between the penstock and the reinforced concrete tunnel; usually the incompleteness of the rock mass around the penstock is treated by grouting the anti-seepage curtain, but it may also form a seepage channel of the reservoir. According to the requirements of the code, it is generally not allowed to open holes...

AI Technical Summary

Problems solved by technology

There is a possibility of internal water seepage at the connection between the penstock and the reinforced concrete tunnel; usually the incompleteness of the rock mass around the penstock is treated with anti-seepage curtain grouting, but it may also form a seepage channel of the reservoir

According to the requirements of the code, it is generally not allowed to open holes on the penstock for various types of grouting. The circumferential consolidation grouting in the hole should be completed before the installation of the steel pipe. For heavy grouting without cover, the compactness and anti-seepage performance of the shotcrete layer are not as good as that of the cast-in-place lining concrete, and the orifice section is the weak link area affected by the excavation and blasting, and there are cases of grout leakage or poor grouting effect. It is possible to connect the upstream and downstream of the curtain to form a water seepage channel, resulting in high seepage pressure downstream of the curtain

[0003] Practice has shown that the water-blocking structure of buried penstocks in the prior art is to install a water-blocking ring at the beginning of the steel pipe and perform anti-seepage curtain grouting in the surrounding rock mass. Function, there are different degrees of defects, resulting in occasional safety hazards of unstable pressure steel pipes due to excessive external water pressure during maintenance, or water seepage in the upstream side wall of the plant, which affects the performance of project benefits. This is a problem worthy of further investigation. research question

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