Notice of RetractionKey technology of constructing the cut-off wall under the foundation with large depth soils layer in Tibet´s Zhikong hydropower station

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

The concrete cut-off wall is a key technology, which applied in preventing seepage in the large depth complicated strata foundation. In Tibetan Zhikong hydropower station foundation engineering, including of the alluvial sand gravel, ice accretion sand gravel, ice-water sand gravel, floating rock and sand layer, the in situ constructing tests of excavating, concreting under water and connecting of two conjoint concrete cut-off wall sects were carried out by the hole-excavating of drill grasp method, drill splitting method and pure grasp method, adjusting the density of slurry in the process of excavating and concreting under water, and placing the conjoint steel pipe after excavating hole. The field experiment of connecting two adjacent cut-off wall sects was also executed by pre-placing the conjoint pipe before concreting, and then pulling the pipe after initial solidification. So the technology of excavating hole in strata, hole wall stability, preventing slurry leakage along the large pore of particles, connecting of adjacent concrete cut-off wall sects and inspecting the quality of concrete wall was applied widely in the condition of complicated strata in Qinghai-Tibetan Plateau. The soil particle grade conditions of slurry leakage in soils strata were revealed by the model testing. It is shown that the excavating depth of hole is over 70 meters in the complicated strata consisting of alluvial, ice accretion, ice-water sand gravel, floating rock and sand layer in Qinghai-Tibetan Plateau. During the excavating- slurry will leak intensively when the pore volume of single particle equals 11mm3.The leakage channels can be blocked up effectively by filling sand gravel and clay. The conjoint of anti-seepage wall could be disposed effectively by setting tie-in pipes in the hole, when concreting in slotted hole. The concrete anti-seepage wall over 70 meters depth in soils strata of Tibetan Plateau has been completed. The constructing technology of anti-seepage wall can- be applied in other engineering with similar geological condition.