The Construction Method Proposal Study On The Excavation And Supporting & Protection Works For Powerhouse Of Liuhong Hydropower Station

The construction method of this research papers is specially made for the excavation, supporting & protection works of the Powerhouses of Liuhong Hydropower Station. The Power Plant is of underground type including Main & Auxiliary Powerhouse, Erection Room, Power Cable Tunnel, Tailrace Tunnel, Tailrace Channel, Traffic Tunnel, Drainage gallery, ventilation tunnel and Switch Yards etc. The Powerhouse is large in span and high in sidewall with a maximum height of 36.5 meters, width of 18.6 meters and length of 81.52 meters of which includes 19.5 meters long for Erection Room, 44.0 meters long for Main Powerhouse and others for Auxiliary Powerhouse. There are totally twelve tunnels connected to the Powerhouse, the wall between tunnels is thin with a poor geology condition and problem of surrounding rock stability. A whole set of construction method proposal is founded depending on the features of Powerhouses such as complex in design structure, a large number of tunnels connected, high sidewall, large span, too many work procedures, high technical requirement, great construction disturb as well as high standard in construction quality, safety and work progress. This construction method proposal study is composed of construction general layout and construction procedures of excavation and supporting & protection works for the Main & Auxiliary Powerhouse. The following work procedures is specially described in detail including the vault excavation, the staircase segment excavation, the protection layer excavation, special place excavation, geological problem handling, and safety control measures of the blasting method during excavation works construction, and anchors rebar construction, pre-stressed anchors cable construction, concrete jet construction and vault consolidating grouting construction during the supporting & protection works construction. It provides a feasible and specific construction method proposal for the excavation of Powerhouse of Liuhong Hydropower Station.Because the excavation, supporting & protection works of the Powerhouse belong to the large-scale hole room group construction, regarding the Powerhouse such important spot, its construction progress, the quality, the safety request extremely is specially strict. In view of the project features of structure complex, too many procedure and great construction disturbs, an entire set of more complete construction procedures and the science reasonable construction method is proposed to overcome the construction conflicts and disturb to speed up the construction progress. "The fine construction" principle is performed during construction. For the important quality control point, the innovation measure and the new construction method are proposed in particular so to provide the practical feasible plan to guarantee good project quality. In sight of the features of large span in excavation, high sidewall, poor geology condition and surrounding rock, too many construction disturb and difficulty in blasting control, the entire process, omni-directional predetermined plan to the safe construction is proposed, and reliable precaution measures is also designed specially for the significant dangerous source to safeguard the project proceeding smoothly.