Geotechnical Aspects of Weak Sandstone from Recife/Brazil

O.M. Oliveira, R. Bim, G.B. Nunes, R.A.R. Higashi

Article

Soils and Rocks, São Paulo, 41(1): 61-74, January-April, 2018 | PDF


Abstract

Diagenetic processes acting on the sandy sediments of the marine plains from the city of Recife/Brazil formed different types of sandstones. Two blocks of the sandstone formed in the Pleistocene epoch were collected to perform characterization tests and determine their mechanical properties. This sandstone is present in a depth between 0.3 and 4.5 mand with a thickness between 0.5 and 4.5 m. The average values obtained for their specific dry weight and porosity are respectively equal 16.5 kN/m3 and 30%. In the unconfined compressive strength tests were obtained mean values of resistance and deformability module respectively, equal to 2 MPa and 162 MPa, classifying this sandstone as weak rock. An isotropic behavior was observed when performing direct shear tests in the direction parallel and perpendicular to the level of the terrain. The sandstone block collected at a greater depth presented higher resistance parameters in these tests with cohesion of 393 kPa and a friction angle of 55.6°. A case study is presented where the geological and geotechnical characteristics of these sandstones were explored as support for a building foundation, and a good performance was observed.


Submitted on August 24, 2017; Final Acceptance on February 21, 2018; Discussion open until August 31, 2018. DOI: 10.28927/SR.411061