Influence of faults on alteration, mineralogy, and geotechnical behavior of granitic residual soils

Autor: Juan Antonio Altamirano Flores, Marcelo Heidemann, Luiz Antonio Bressani
Rok vydání: 2021
Předmět:
Zdroj: Bulletin of Engineering Geology and the Environment. 80:7051-7068
ISSN: 1435-9537
1435-9529
Popis: Contact metamorphism and metasomatism are imposed on granitic rocks by late intrusions. This study shows the consequences of this phenomenon on the pedogenesis of granitic rocks and on the geotechnical properties of granitic residual soils. This study comprises two saprolitic soils formed from the same granitic body in a site located in the Southern Brazil Coast. A biotite-rich residual soil (BR soil) was formed in the vicinity of a dyke that crosses the study area and concentrates a history of landslides. The second soil, a red saprolitic residual soil (RR soil), was formed far from the intruded fault. Chemical, physical, and mineralogical characterizations were carried out to describe the materials and the changes imposed by their alteration. Effects of alteration on the soil’s behavior were assessed in terms of hydraulic conductivity, one-dimensional compressibility, and shear strength. Both soils presented a fragmented structure and cataclastic texture over feldspar matrices. The good drainage conditions induced the development of large amounts of kaolinite. Suction values increase with the alteration level and hydraulic conductivity decreases. Under oedometric loading BR soil is stiffer than RR soil, despite its higher porosity. RR soil has higher shear strength than BR soil, which explains the history of landslides that mobilize this soil.
Databáze: OpenAIRE
Externí odkaz: