Geología y geotecnia del Proyecto Hidroeléctrico Huites, Mpio. de Choix, Sinaloa

http://dx.doi.org/10.18268/BSGM1985v46n1a1

Leovigildo Cepeda Dávila*, Jorge Hernández Samayoa*, José Luis Valencia Cruz* y Jaime R. Vallarino Guzmán*

*Unidad de Estudios de Ingeniería Civil. Comisión Federal de Electricidad.

Abstract

The Huites dam will generate 888 GWH per year, it will open 464 km² to irrigation and improve the efficiency of the 2,420 km² that constitutes the Miguel Hidalgo and Josefa Ortiz de Domínguez dam system. The stratigraphic column is made up of phyllites, schists and amphibolites of possible Paleozoic age, Jurassic metavolcanics, metamorphosed and nonmetamorphosed Jurassic-Cretaceous limestone, Late Cretaceus detritic metasediments, Late Cretaceous-Paleocene granites and granodiorites that affected the rocks previously mentioned, tertiary red sandstones and conglomerates, ignimbrite sequence and variegated sandstones and conglomerates, and Quaternary basalts, dolerite and andesite sills and dikes, piedmont sediments and alluvium. Granite, hornfels (metavolcanics and metadetrital sediments), ignimbrites, dolerites, eluvial and alluvial deposits are exposed in the dam site.

Tectonically, the site shows evidence of distensive stresses that combined with the joints, results in a block faulting that affects the whole stratigraphic column. Two prevailing fracture patterns have been defined: NW-SE (in accordance with regional faulting) and NE-SW, that usually shows as subvertical normal faults and inverse faults with similar inclination. From the geotechnical point oí view, the Huites dam is feasible with any of the tWO proposed schemes: a zoncd-earth fill dam or a concrete gravity dam. Even though the site is faulted it does not represents high strucrural risk for the stability of dam itself and the slopes; it is considered that the risk of piping through the discontinuities is minimal.