Geomechanics and Engineering

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Bearing capacity of shallow foundations on the bilayer rock

  • Alencar, Ana S. (ETSI Caminos, C. y P., Technical University of Madrid (UPM)) ;
  • Galindo, Ruben A. (ETSI Caminos, C. y P., Technical University of Madrid (UPM)) ;
  • Melentijevic, Svetlana (Faculty of Geology, Complutense University of Madrid (UCM))
  • Received : 2019.06.17
  • Accepted : 2020.03.02
  • Published : 2020.04.10
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Abstract

The traditional formulations for estimation of bearing capacity in rock mechanics assume a homogeneous and isotropic rock mass. However, it is common that the rock mass consists of different layers of different rock properties or of the same rock matrix with distinct geotechnical quality levels. The bearing capacity of a heterogeneous rock is estimated traditionally through the weighted average. In this paper, the solution of the weighted average is compared to the finite difference method applied to a bilayer rock mass. The influence of different parameters such as the thickness of the layers, the rock type, the uniaxial compressive strength and the overall geotechnical quality of the rock mass on the bearing capacity of a bilayer rock mass is analyzed. A parametric study by finite difference method is carried out to develop a bearing capacity factor in function of the layer thickness and the rock mass quality expressed in terms of the geological strength index, which is presented in a form of a chart. Therefore, this correlation factor allows estimating the bearing capacity of a rock mass that is formed by two layers with distinct GSI, depending on the bearing capacity of the rock mass formed only by the upper layer and considered by that way as homogenous and isotropic rock mass.

Keywords

Acknowledgement

Supported by : Jose Entrecanales Ibarra Foundation

The research described in this paper was financially supported by the José Entrecanales Ibarra Foundation.

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