Study On The Key Problems Of Prestressed Pier Anchor Cable Of The Second-stage Engineering In Guangxi Yujiang Laokounavigation Junction

In the water conservancy project,the pier is an important part of the drainage structure,which plays the role of the separation between the gate and the gate.With the development of water conservancy and hydropower technology and steel structure in water conservancy and hydropower project,sluice hole is constantly widening,the safe operation of the pier are increasingly high requirements,The conventional pier structure must not be adopted only by increasing the reinforcement ratio and thickened pier size in this case,prestressed anchor pier came into being.Along with our country successfully applied the construction of prestressed pier anchor cable technology to the Gezhouba water conservancy hub for the first time in the 1970s,through the development of recent decades,the process has become relatively mature,which is widely adopted the Bridges,hydropo wer and other parts in the current domestic.At present the application of the construction technology of prestressed pier anchor cable in pier usually embed anchor block in advance,with long steel pipe after pouring in the pier at the same time.After the strength of the concrete age reach the specification requirement,erecting scaffolding on both sides of the pier to do a good job in construction platform,and then anchor cable perforati on,tension by manual and start the corresponding hole sealing grouting work accordingly.The prestressed anchor cable has been used in the pier of the overflow gate of the second-stage engineering in Guangxi Yujiang Laokou,and the anchor hole of the construction design is embedded with bellows,reinforcement with steel disk at the same time.The construction method has problems of a large number of corrugated pipe,which is the flexible structure,easily to produce crack in the process of concrete casting,and lead to lower pore forming rate,The construction is difficulty.And prestressed anchor cable tensioning usually adopt the erection bent or do the steel structure platform construction,it also has problems of long project construction time?too high cost and lower security problems.In order to solve the above problems of the quality,safety and schedule,basing on the existing researched results and Through the study on the key problems of quality,safety and schedule,Improve and perfect the old Port Phase II project in Guangxi Yujiang river pier construction technology and construction method of prestressed anchor cable and achieve good benefit.In this paper,the key issues in the construction process of the prestr essed pier of the second-stage engineering in Guangxi Yujiang Laokou hydropower station are studied.Presents to use the steel pipe instead of the engineering corrugated pipe,and adopts the embedded steel beam and hoist to tension the anchor hole to replace the commonly used erection method or steel structure platform to avoid the construction mechanics proble m encountered in the method of lifting operation.The method of the technical problems encountered in our researches,Theory should be based on practice,to solve the pier in engineering mechanics problems arising in the course of prestress tension and other key issues encountered in the construction.The main results are as follows:This paper applies the theory to practice,and uses the steel pipe inst ead of the engineering corrugated pipe,and adopts the embedded steel beam and hoist to tension the anchor hole to replace the commonly used erection method or steel structure platform to avoid the construction mechanics problem encountered in the method of lifting operation.The relevant calculation method and structure chart are established by using the relevant theories and knowledge of engineering mechanics to solve the engineering mechanics problems of the pier in the process of the prestressing tension and as well as other key issues encountered in the construction.The main results are as follows:1?Demonstrated the feasibility of using steel pipe instead of corrugat ed pipe.The construction method and construction scheme of steel pipe instead of corrugated pipe are put forward,and it has optimized and verified in the anchorage cable construction of the second-stage engineering in Guangxi Yujiang Laokou.2?Demonstrated the use of embedded steel girder and hoisting machine on the anchor cable hole construction method instead of the commonly used erection of the platform or do the construction of steel platform lifting operation of the method of operation are maneuverability.The corresponding construction methods and Construction plan are put forward,and it has optimized and verified in the anchorage cable construction of the second-stage engineering in Guangxi Yujiang Laokou.