Study On The Arrangement Of Main And Secondary Ropes And The Anchor Hole Shape Of Prestressed Pier In A Spillway

The prestressed pier is a common supporting structure of of large arc gate,which is mainly used to separate the sluice bore,bear the thrust of radial gate and often act as the supporting body of the bridge on the dam crest.It plays an extremely important role in large water conservancy project.However,with the increasing of the arc gate,large tensile stresses will occur in key parts such as the anchor block,the neck of the pier,and the anchor hole,and the stress situation will be complicated.In order to improve the prestressed effect of gate pier,many scholars have done relevant research on the structure of the pier neck and the anchor block.but at present the pulling-anchor Coefficient is relatively large in China,and the arrangement of the primary and secondary anchor ropes is mainly based on the design of engineering experience,and the traditional trapezoidal anchor hole type gate pier is not good.There are few researches on the arrangement types of main anchor rope and secondary anchor rope and anchor holes in the existing research,so it is necessary to conduct in-depth research on the layout of main anchor rope and secondary anchor rope and the shape of anchor hole.Taking the prestressed middle pier of a spillway in an actual project as the research object this paper studies the influence of the main anchor rope layout type,the secondary anchor rope layout type and the shape of anchor hole on the stress of the key parts such as anchor hole,pier neck and anchor block.The influence of the number of main anchor ropes,the thickness of protective layer and the coefficient of anchor on the stress of key parts of the prestressed pier are studied;The necessity of the secondary anchor rope is demonstrated according to the stress characteristics of the anchor block,the effect of the number and tonnage of the secondary cables on the stress of the key position of the prestressed pier is further studied;Aiming at the problem of large tensile stress on the top and downstream surfaces of traditional trapezoidal anchor holes,the top surface of the anchor hole was designed from a plane to a curved surface,and the influence of its paramcters on the stress of the anchor hole was studied.The results show that under the condition of constant total anchoring force,with the increase of the number of main anchor ropes,the tensile stress values on the top and downstream of the anchor hole decrease,and the compressive stress values on the anchor end of the main anchor rope also decrease;With the increase of the thickness of the protective layer of the main anchor rope,the tensile stress value on the top and downstream faces of the anchor hole decreases first and then increases,and the tensile stress value at the neck of the pier increases;Increasing the pulling-anchor Coefficient can effectively reduce the tensile stress at the neck of the pier,but at the same time,it will increase the tensile stress and compressive stress around the anchor hole and downstream of the anchor block.The secondary anchor rope arrangement can effectively reduce the tensile stress on the anchor block due to the main anchor rope and the arc door thrust;The reasonable design of the number and tonnage of the secondary anchor ropes is beneficial to the stress status inside and around the anchor block.Designing the top surface of the anchor hole from a flat surface to a curved surface can effectively reduce the tensile stress on the top surface and the downstream surface of the anchor hole;The shape parameter ? of curved anchor hole has a great influence on the tensile stress on the top surface of the anchor hole,with the increase of parameter 0,the tensile stress on the top surface of the anchoring hole decreases,When parameter 0 increases to 90°,the top surface of the anchor hole is tangent to the downstream surface of the anchor hole,and the overall force effect of the anchor hole is better.The results of this paper can provide reference for the layout of main and secondary cables of the prestressed pier and the shape design of anchoring holes.