In this paper are analized the first results obtained in the analysis of the morphology of the fracture surfaces originated in rock - samples subjects under uniaxial compression, as a consecuence between the Composition and distribution of the plannar anisotropy preexistance.
In this paper are analized the results obtained in the analysis of the relation into the morphology of the fracture surfaces and the disposition of the preexistance structural discontinuities,in rock samples proceding from the next Large Dams:
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San Esteban
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Ricobayo
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Almendra
Geologicaly,the unalized rocks are Gites and belongs to group of Hercinian Granites in the classification of den Tex (1966),and inside of this group in the Formation definited for The Geological and rnineralogical Spanish Institute as Granite orienated with two micas. Thrugh polarizing microscope,shows an orientated texture with a grain and micrograin structure,and it's major mineralogic components are Quartz presenting ondulated extinction Potasic Feldspars as Microclin~, Plagioclases as Albite,and Biotite and Muscovite micas very deformed, as additional minerals appears Sericite,Clorite and Zircon,which is lncluded jnto the Biotite crystals.
Since geological point of view, the analized rocks arise from Granodiorite of Ricobayo Formation which - appears as elongated grounding,being paralell to the structures.
According to IGME (1982),this Formation belongs to Group of Calco- Alcalines Granites,which developed a thermal metamorphism.
About it constitution and texture, it is a homogeneus rock,grained, with a medium size and two micas, and it shows to be orientate and deformed occasionally.
Through polarizing microscope shows an holocrystalline texture,hipidiomorphic, and its major components are Plagioclases,Ologoclase,Potasic Felds pars,Qllartz,Muscovite and Biotite. - As additional minerals anpears other as the Apatite, Turmalineand Zircon.
The analized samples of Almendra Dam are Granites Adamellitics,and its - shows a constant composition.
Through microscope shows an holocrystalline texture and its major mineralogical components are Quartz with ondulated extintion, Potasic Felspars,rlicrocline,Plagioclases with Albite and Carlsbad twins,and Biotite and Muscovite micas.
As additional minerals appears Apatite, Zircon and Turmaline, unusualy Cordierite Sillimanite and Andalucite, near meoamorphic contact zone.
The results obtained in uniaxial compression realized in samples from- Dams before described, shows which its comporting in fracture is tie intimate with the disposition on the structural discontinuities preexistences.
As a whole of the realized tests, has been selected three representative samples of three modes of comportament observed:
The sample testing of the San Esteban Dam, shows a pronunced structural discontinuity, schistosity defi nite for the position of the micaoeous minerals..
Fig. 1 San Esteban Dam sample before test
The compression axis in test its for ming an angle from 35 Degrees with - the surface of the schistosity.
Fig. 1 Fig. 2 San Esteban Dam sample after test The results of the test, Fig. 2,shows clearly the relation between the dis position of the fracture plane and the structural plane existent.
