1、附录 2 ESEARCH ARTICLE Eduardo E. ALONSO, Rafaela CARDOSO Behavior of materials for earth and rockfill dams: Perspective from unsaturated soil mechanics Higher Education Press and Springer-VerlagBerlin Heidelberg 2010 Abstract ： The basis of the design of earth and rockfill dams is focused on ensuring
2、 the stability of the structure under a set of conditions expected to occur during its life. Combined mechanical and hydraulic conditions must be considered since pore pressures develop during construction, after impoundment and in drawdown. Other instabilityphenomena caused by transient flow and in
3、ternalerosion must be considered. The prediction of the hydromechanicalbehavior of traditional and non-traditionalmaterials used in the construction of dams is thereforefundamental. The materials used for dams constructioncover a wide range from clayey materials to rockfill. In abroad sense they are
4、 compacted materials and thereforeunsaturated materials. A summary of the current level ofknowledge on the behavior of raditional materials used inthe construction of dams is presented in the paper. Regularcompacted materials (with a significant clay fraction),rockfilland ompacted soft rocks are stu
5、died with moredetail. The latter are non-traditional materials. They areanalysed because their use, as well as the use of mixtures ofsoil and rock, is becoming more necessary for sustainabilityreasons. Keywords： ams, unsaturated soil mechanics, suction,rockfill, clayey soil, mixture 1 Introduction T
6、he basis of the design of earth and rockfill dams is focused on ensuring the stability of the structure under a setof conditions expected to occur during its life. The stabilityof the upstream and downstream slopes must be guaranteed at the end of the construction but also during reservoir impoundme
7、nt and the operational phase, including drawdown and long-term steady state conditions as a limiting case. A fundamental aspect of the analysis is the generation of pore pressures during the construction and during the first filling, reservoir impounding and cases of rapid drawdown. Other aspects ar
8、e also of concern, such as the deformation of the structure during the construction andoperational stages, and also incidents caused by hydraulicfracture, internal erosion, long term effects and othercombined cases. Failures associated with hydraulic fracture and internal erosion is largely reported
9、 in the literature. Two recent cases of failure caused by collapse and internal erosion are presented in the first part of the paper. The hydromechanical behavior of the materials used in the construction of the earth structures are used to explain their failure. An additional source of complexity i
10、s the fact thatdifferent types of materials are used. For traditional dams,impervious clayey materials are used for the core, rockfillmaterials (any type of rock) are used for shells and granularmaterials are used for filters. However, for sustainabilityconstraints and environmental reasons, the use
11、 of marginalmaterials, i.e., materials that traditionally would not beused in the construction of dams, is becoming frequent.Such is the case of soft rocks or evolving rocks and soil orrock formations with some proportion of evaporites. Figure 1 is a photograph of Lechago Dam in Teruel,Spain. A very
12、 traditional design was adopted. Threedistinct zones can be distinguished: the core, built withregular compacted soils (low to medium plasticity sandyclays, clayey sands and clays), the shoulders built withindurated shale rockfill and the filter built with finegranular materials. Other solutions are
13、 also adopted in thedesign as a consequence of the available material for theconstruction. For example, rockfill materials can be usedcombined with solutions adopting impervious materials, aswell as compacted soft rocks. Figure 2 shows the rockfillslopes of Caracoles Dam in San Juan, Argentina, acombined solution using rockfill, made of alluvial boulders, gravels and sands, and an upstream concretediaphragm. Compacted soft rocks are also used in the constructionof dams and Albags Dam, Lleida (Spain) is an example(Figure 3 shows an
