Paper Keywords: 1 to 10 # dam section of the Three Gorges Power Stationpenstock fabrication and installation
Abstract: 1 # to 10 # dam section of the Three Gorges hydroelectric station penstock diameter of 12.4m, material, respectively, for 60kgf/mm -class high-strength low-alloy quenched and tempered steel and 16MnR steel, with a large diameter, pipe wall thickness, higher technical requirements features. Steel pipe in the production, transportation , erection, installation and welding processes are used some new technology, control of the whole process of the construction process to ensure that the Three Gorges Left Bank penstock fabrication and installation quality. The accumulated experience for the construction of large-diameter penstock.
1, an overview:
There are 10 units of the monolith A section of the Three Gorges Project Left Bank Power House inlets, each inlet were set to have a diversion penstock unit using the stand-alone single-tube the way of water supply. Intake penstocks design diameter of 12.4m, the maximum design water pressure of 1.4MPa is currently on the diameter of the largest water diversion penstock steel lined reinforced concrete, the structural form of the joint force layout on along the water into the dam segment, behind the dam pipe section and the lower horizontal section back Stake from 20 +024.172 to 20 +118.00 central axis installation the elevation EL113.584 ~~ EL57.000m, dam section (on the ramp straight section) is made of 16MnR, plate thickness 26mm, the dam back tube curved segment inclined straight segment, bending under the paragraph on the curved segment, the inclined straight section made of 16MnR, plate thickness 28 ~ 34mm, the next bend, the next level of material 60kgf/mm 2- stage high-intensity tone and tempered steel , thickness 34 ~ 60mm. 1 # 6 # Section penstock next level segment set the elastic cushion pipe, single pipe axis of long 120.122m Quantities 1446t; 7 # 10 # Monolith pressure steel pipe next horizontal section to set the sleeve-type expansion joints, single pipe axis of long 112.852m Quantities 1278t; 1 # 10 # dam section of quantities of a total of 13788t.
2, the relationship between the pipeline and related constructionmaterial:
The relationship between 2.1 and dam concrete construction:
1 # 6 # Section of part of the back of the monolith bedrock elevation ranging from left factory tube I stay trough the form of excavation, left Factory 7 # to 10 # Section the penstock I stay trough the concrete pouring made. Dam within the pipe segment rise formed simultaneously with the dam concrete, the dam blocks pouring tube to install the elevation and age of more than 7 days, both sides of the non-steel pipe monolith rose to the elevation of 110m or more, before that portion of pipe installation.
2.2 and payment of the relationship of the plant:
Conduit bend section and horizontal section arranged in the lower part of the payment of plant, steel monolith tube while I stay trough formed on both sides of non-steel pipe monolith to achieve elevation 82m, the lower part of the horizontal segment of pipe installation, and from next bend paragraph, section by section up installation.
2.3 Filling of the dam longitudinal seam:
Longitudinal slit dam, pipeline I stay trough across two longitudinal seam steel pipe installation until the corresponding longitudinal seam completed on the pipe installation above the elevation, the installation of the steel pipe.
2.4 and I stay in the groove relationship:
Prior to installation, civil engineering and construction preparation work must be completed after the end of the pipe installation, concrete backfill placement of the pipe.
3, the production of the penstock:
3.1 steel pipe production materials
3.1.1 The parent material
All steel for steel pipe manufacturing design requirements and construction drawings shall comply with the provisions of the factory of steel pipe base metal 16MnR and 60kgf/mm, high strength steel in steel mills, ultrasonic testing of pressure vessels, "(ZBJ74003-88), 100 % flaw detection, each batch of steel plate shall be factory certificate, the base metal chemical composition and performance should meet the following requirements:
(1) 16MnR steel plate chemical composition (%)
C |
Si |
Mn |
P |
S |
Ni |
Cr |
Mo |
≤ 0.02 |
0.20 to 0.60 |
1.20 to 1.60 |
≤ 0.035 |
≤ 0.035 |
|
|
|
(2) 16MnR steel plate mechanical performance
Sample Specification |
Sampling Location |
of σ s (Kg / mm 2 ) |
of σ b (Kg / mm 2 ) |
δs (%) |
Cold bending performance d = 3a 180 ° |
Low temperature impact toughness VE-20 ℃ J |
GB |
Transverse |
31 |
50 to 65 |
≥ 19 |
Intact |
≥ 27 |
(3) 60kgf/mm2 high strength steel chemical composition (%)
C |
Si |
Mn |
P |
S |
Ni |
Cr |
Mo |
≤ 0.09 |
0.15 to 0.30 |
1.0 to 1.6 |
≤ 0.030 |
≤ 0.030 |
≤ 0.60 |
≤ 0.30 |
≤ 0.30 |
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