NEW MATERIALS FOR SAFE FILL DAMS
In fill dams, the impervious layer is placed at the upstream face (CFRD, asphalt concrete), or in central position (clay, asphalt concrete, bentonite cores). These systems entail difficulties in design, availability and placement of materials, construction, and quality control. Performance is not always as expected, often due to inability of the impervious layer to accommodate settlements at foundations, settlements due to bad compaction, seismic events, etc. A waterproofing system made with a flexible PolyVinylChloride (PVC) geomembrane is more efficient in accommodating without breaking very large settlements, and differential movements between the deformable dam body and the concrete appurtenances. While the quality of traditional waterproofing materials depends on local situation, geomembranes have constant controlled properties and quality. Geomembranes allow reducing constraints related to type and grading of fill material, to thickness and type of filter layer. The dam can be constructed with a large range of locally available materials. A new unconventional system, exploiting at best the properties of PVC geomembranes, has been developed and is under consideration for several fill dams. The system embeds flaps of PVC geomembrane in an upstream base layer, while the dam is being raised. The impervious PVC geomembrane liner is deployed over the dam face and anchored by welding to the PVC flaps. A watertight perimeter seal, designed to follow the differential movements between the fill and the rigid concrete appurtenances (intake towers, spillways, etc), completes the system. This new waterproofing system is more effective and reliable because all its components are flexible and designed to follow all possible settlements and differential movements. It is also designed for extremely strong anti-puncturing resistance. The PVC system can be constructed concurrent with raising of the dam fill, reducing times and costs of the entire dam construction, and allowing more simple construction by companies with limited previous experience. The paper discusses design, installation, advantages compared to traditional systems, and a pilot project at Toulnustouc CFRD, Canada.
Geomembrane Geocomposite Deformability Settlements Seepage
A.M.Scuero G.L.Vaschetti
C.S.Gottardo 86, 6830 Chiasso, Switzerland C.S.Gottardo 86, 6830 Chiasso, Switzerland
国际会议
西安
英文
1-10
2005-11-01（万方平台首次上网日期，不代表论文的发表时间）