Effect of opening of joints on the behavior of concrete dams during operation

Autor: Vovkushevskii, A. V., Trapeznikov, L. P., Sheinker, N. Ya., Ginzburg, S. M., Yudelevich, A. M.
Zdroj: Power Technology and Engineering (formerly Hydrotechnical Construction); February 1995, Vol. 29 Issue: 2 p73-76, 4p
Abstrakt: Conclusions 1.Theoretical investigations confirmed considerable opening of the contact joint both in nonoverflow and especially in powerhouse sections of the Bratsk dam. Other conditions being equal, the length of the zone of opening of the contact joint in the powerhouse sections is 2–3 m greater than in the nonoverflow sections.2.Opening of joints has a seasonal character. In the winter the zone of opening in the powerhouse sections reaches the grout curtain (9–10 m from the upstream face), in the summer it is about half as much.3.Such opening of the contact joint together with the phenomenon of decompression of the foundation leads to an increase of the uplift pressure, increase of seepage discharges, and decrease of safety against shearing. In turn, an increase of uplift pressure can lead to an increase of the zone of opening of the joint by 1–2 m.4.A decrease in the winter of the upper pool level from the NPL (402 m) to 398 m brings the contact zone into about the same state as in the summer at the NPL.5.Calculations showed that the zone of opening of the contact joint can be followed by a closed joint zone with displaced surfaces (sliding zone) and only then does the remaining part of the joint have an undisturbed initial strength. The size of the sliding zone depends on many factors and requires further refinement, but in any event this zone can completely enter the second column.6.In the future we must refine the state of the contact zone in various sections with a more accurate consideration of the characteristics of the contact joint (friction with the initial strength) and with consideration of decompression of the foundation or the formation of cracks in it, seepage in the foundation, and effect of opening of the column joints.
Databáze: Supplemental Index
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