SCS combined hydropower station pressure underground pipe design method

Abstract

The invention discloses a way to design pressing tube of SCS combined hydraulic power station. Between the steel inside and the round wall fill concrete tube, between the concrete tube and the round wall fill the outside steel tube. The outside steel tube is anti-seepage , the middle concrete tube resists external pressure, and the inside steel tube only resists water pressure inside when operating. It decrease by large the content of steel and concrete and the cost, and it is convenient to transfer the water pressure from inside to outside. The way of design brings the good capability of steel and concrete into play, and apt to the work environment very well. Otherwise, in operation there is no need to add other ways, so it increases the speed of the operation by large.

Description

technical field [0001] The invention relates to a design method for a pressure buried pipe of a hydropower station, in particular to a design method for a steel lining-concrete-steel lining (SCS) combined type hydropower station pressure buried pipe. Background technique [0002] In the past 20 or 30 years, the use of underground buried pressure steel pipes has been increasing. On the one hand, it is because of the massive construction of underground power stations; secondly, there are many engineering pipelines along the unfavorable ground conditions, out of the need to protect the environment; thirdly, due to the current The HD value of penstocks continues to increase, and it is more and more difficult to design and manufacture open pipes. High-strength alloys are expensive and in short supply. The use of underground buried penstocks can use the surrounding rock to share the load and reduce the thickness of the steel lining. [0003] However, as the single-unit capacity of...

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Problems solved by technology

[0004] (1) Under the action of high internal water head during the operation period, if the concrete lining is designed to resist cracking, it is necessary to thicken the concrete lining and increase the concrete grade, thereby expanding the excavation section and bringing inconvenience to the pouring of the concrete lining, and it is also not conducive to Transfer the internal water load to the surrounding rock;

[0005] (2) The general concrete lining is designed according to the crack limit, which brings another difficulty. During the maintenance period, the external water will directly act on the steel pipe wall through the cracks in the concrete lining. It often becomes the control working condition, which requires thickening the distance between the steel plate and the densely reinforced ring and increasing the size of the reinforced ring. However, the hoop stress in the steel lining is often very small during normal operation, and its tensile strength cannot be fully exerted. role, thus wasting steel and bringing great inconvenience to construction;

[0006] (3) In order to give full play to the tensile effect of the steel lining, a reserved joint is set between the steel lining and the concrete lining. Although the tensile effect of the steel lining can be exerted as much as possible, it will cause damage to the external water during the maintenance period. The stability of the steel lining brings fatal hidden dangers, and the design of relying on measures such as stiffening rings to increase the stability of the maintenance period brings great trouble to the construction, and at the same time, the cost of construction and installation increases sharply

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