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ABSTRACT: The aim of this study is the estimation of Lugeon values at the abutments of Chicoasén Dam site. A 3D-neurofuzzy modeling is proposed for solving the task. The hybrid approach relates the rock mass descriptors and the Lugeon test information to obtain a natural display of the hydraulic conductivity. The symbiotic symbolic/numeric processing is able to perform the crucial engineering responsibilities of configuration, diagnosis, interpretation, analysis and planning, thorough intelligent numerical interfaces and adaptive 3D-database stores.
1 INTRODUCTION
In recent years, the evaluation of dam site properties has caught the attention of many researchers (e.g. Lashkaripour and Ghafoori, 2002; Romanov et al., 2003; Ghobadi et al., 2005; Kocbay and Kilic, 2006; Unaletal., 2007; Ghafoori etal., 2011; Uromeihy and Farrokhi, 2012) being the permeability of rock masses one of the most challenging items to be studied. Scientist have assumed that local geological structures, discontinuities properties and degree of weathering determine the differences in hydraulic conductivity (Bell, 2007) but they have not been certain of the particular conditions that are more responsible, and the degree to which they affect the different consequences levels. The key aspect in these investigations is the accurate determination of the relationship between the discontinuity properties and the hydrogeological behavior of the rock mass.
There is an intuitive suggestion that the water pressure test or Lugeon test (Lugeon, 1933), one of most common tests in the evaluation of the rock mass permeability (Nonveiller, 1989; Houlsby, 1990; Ewert, 1997) is directly associated to the RQD index (Deere, 1963). However, as inputs when evaluating the hydrogeological conductivity of test sections sometimes these parameters show contradictory effects: a region with a low degree of jointing (high RQD) shows high absorption or vice versa (Foyo et al., 2005). These unsound behaviors can be explained through i) the noise and errors in the RQD determination (Hudson and Priest, 1983; Houlsby, 1990; Ewert, 1997; Palmstrom, 2005; Bell, 2007) and/or ii) the hydraulic conductivity, obtained from the Lugeon test, is only representative for a limited cylinder of rock (Bliss and Rushton, 1984).
In this research, a set of geological and geotechnical analyses, performed on the rock mass of a dam site (both abutments), is used to attain an inclusive hydrological zonation of the site. The proposed scheme is...