Construction of Rockfill Dams with Geomembrane Face:Bovilla and Sar Cheshmeh
Impervious geomembrane systems,widely used in rehabilitation of CFRDs,are being adopted to substitute concrete facings in new rockfill dams,because they avoid the problems related to inadequate installation of waterstops,and to deterioration of waterstops and/or concrete slabs due to settlements,differential movements,weathering,seismic events. Additional advantages are reduced construction times and costs.Significant examples of geomembrane facings on new rockfill dams are Bovilla in Albania and Sar Cheshmeh in Iran.Bovilla,91 m high,was originally designed as a concrete face rockfill dam.Difficulties in construction,concerns about the final quality of the concrete facing,potential for future cracking of the slabs,and the need to reduce construction costs and bring the project back to schedule,suggested changing the original design to an upstream geomembrane system. The impervious liner is a geocomposite consisting of a polyvinylchloride (PVC) geomembrane laminated during fabrication to an antipuncture geotextile,and ballasted with thin unreinforced concrete slabs.With>230% elongation at break and perimeter seals conceived to follow differential movements,the system fulfils two crucial requisites:good deformability allowing resisting large differential settlements even in case of seismic events,and complete watertightness. The new design allowed completing the project ahead of schedule and at lower costs.Sar Cheshmeh is a 70 m high tailings dam where an upgrading project carried out in 2008 included heightening by about 19 m the main embankment and saddle dam No.1. The raising consists of a zoned rockfill with an upstream exposed PVC geocomposite as impervious component. The PVC geocomposite is placed on extruded porous concrete curbs and is anchored to the curbs by PVC strips. This new unconventional design provided a waterproofing system totally deformable,hence capable of accommodating all differential movements that can occur during service,granting a safe dam that was constructed easily,in shorter times,and at lower costs.Future stages will raise the dam to a total added height of 40 m. The paper discusses the process leading to the selection of the geomembrane systems,the design and installation,the advantages achieved,and up-to-date performance.
dams upstream geocomposite geomembrane eztruded curbs PVC deformable anchorage
Scuero A. Sembenelli P. Vaschetti G.
Carpi Tech,Corso San Gottardo 86,6830 Chiasso,Switzerland SC Sembenelli Consulting,Via Santa Valeria 3/5,20123 Milan,Italy
国际会议
The 1st International Symposium on Rockfill Dams(第一届堆石坝国际研讨会)
成都
英文
493-503
2009-10-18（万方平台首次上网日期，不代表论文的发表时间）