Abstract:

To provide basis for the concrete quality control for Xiluodu dam, we carried out in-situ shear test on normal concrete layers which are poured from the raw material with mix proportion identical to the actual concrete of Xiluodu dam. Results showed that friction factor f'  and  cohesion c'  of the bond surface between concrete layers were respectively between 1.44-0.97MPa and 3.00-1.85MPa, while  f'  and c'  of concrete itself were 1.80MPa and 3.145MPa respectively. When the maximum normal stress σ_max  was 7.12MPa, the ultimate shear strength  τ_max  of concrete itself was 15.96MPa, and  τ_max  of the bond surface between concrete layers was between 9.67-12.11 MPa. Except from the concrete itself, concrete layers connected with paved mortar has the highest ultimate shear strength. The treatment of  exposing coarse sand on the old concrete surface then paving mortar worked best, and the effect of using rich mortar for the upper concrete was favorable. Shear failure of the specimens with concrete layers occurred on the bond surface, and the shearing plane was generally flat. But the concrete itself had uneven failure surface and most of the largest aggregates were sheared off.  

Key words: Xiluodu hydropower station, concrete, in-situ shear test, shear parameters, shear strength