Technological Innovations In Construction Of Spillway Piers Of Sesan Hydropower Station,Cambodia

The number of hydropower projects with high dams is rapidly decreasing in China with the development boom in the recent decades,while the development rate of hydropower resource in the basins with flat terrain is still low.In the recent years,the planning of tubular turbine hydropower station has an increasing tendency,and the bulb turbine generator is preferred in many hydropower projects.For a wide river with large flow rate,tubular turbine hydropower station seems to be the optimal choice,which leads to significant economic benefit.In run-of-river hydropower stations,for efficiently discharging flood in flooding season,dams with a number of sluices must be designed.Sluice piers are thus necessary,even though the construction of piers is complex and difficult.Therefore,it is of great significance to study how to improve the construction efficiency,save the construction cost,and complete the project as scheduled or in advance.The technological innovations presented in this paper can be applied in the construction of low falling head tubular turbine hydropower station,which may lead to great economic benefits.The large-rising-layer construction technique of piers is studied and applied in practice.The study contains the design and application of the fixed type steel formwork of piers with large rising layer,the design of the installation procedure of rebar and anchor cable embedded pipe,the fast installation of rebar and formwork,the placing technique of concrete,the analysis of economic benefits.It is shown that the fixed large rising layer formwork has an obvious advantage over other methods in cost control and in the on-site installation and removal.The installation and removal of the fixed large rising layer formwork is fast,safe,and reliable,and it can significantly shorten the time required by formwork construction.In addition,the stability of the present technique ensures large rising layer concrete placement,which can reduce the disturbance of layer separation and shorten the construction schedule.The fixed large rising layer formwork has a positive effect on the construction of overflow dam,and it can be applied to similar projects.Furthermore,the rebar work,mix proportion ofconcrete,and concrete placement technique are studied in the present paper,and some experience on site construction management and pier fast-rising construction is concluded.The optimal solutions to the rebar work,concrete mix proportion,and concrete placements are applied in the present project,which play a positive role in shortening the construction schedule of piers and saving the cost of site management.