Paul Marinos

Bio: Paul Marinos is an academic researcher from National Technical University of Athens. The author has contributed to research in topics: Rock mass classification & Geological Strength Index. The author has an hindex of 17, co-authored 47 publications receiving 2783 citations.

Gsi: A Geologically Friendly Tool For Rock Mass Strength Estimation

Abstract: This paper presents a review of the estimation of rock mass strength properties through the use of GSI The GSI classification system greatly respects the geological constraints that occur in nature and are reflected in the geological information A discussion is given regarding the ranges of the Geological Strength Index for typical rock masses with specific emphasis to heterogeneous rock masses

Estimating the geotechnical properties of heterogeneous rock masses such as flysch

Abstract: The design of tunnels and slopes in heterogeneous rock masses such as flysch presents a major challenge to geologists and engineers. The complex structure of these materials, resulting from their depositional and tectonic history, means that they cannot easily be classified in terms of widely used rock mass classification systems. A methodology for estimating the Geological Strength Index and the rock mass properties for these geological formations is presented in this paper.

The geological strength index: applications and limitations

Abstract: The geological strength index (GSI) is a system of rock-mass characterization that has been developed in engineering rock mechanics to meet the need for reliable input data, particularly those related to rock-mass properties required as inputs into numerical analysis or closed form solutions for designing tunnels, slopes or foundations in rocks. The geological character of rock material, together with the visual assessment of the mass it forms, is used as a direct input to the selection of parameters relevant for the prediction of rock-mass strength and deformability. This approach enables a rock mass to be considered as a mechanical continuum without losing the influence geology has on its mechanical properties. It also provides a field method for characterizing difficult-to-describe rock masses. After a decade of application of the GSI and its variations in quantitative characterization of rock mass, this paper attempts to answer questions that have been raised by the users about the appropriate selection of the index for a range of rock masses under various conditions. Recommendations on the use of GSI are given and, in addition, cases where the GSI is not applicable are discussed. More particularly, a discussion and suggestions are presented on issues such as the size of the rock mass to be considered, its anisotropy, the influence of great depth, the presence of ground water, the aperture and the infilling of discontinuities and the properties of weathered rock masses and soft rocks.

Applicability of the geological strength index (GSI) classification for very weak and sheared rock masses. The case of the Athens Schist Formation

Abstract: The Athens Schist Formation includes a wide variety of metasedimentary rocks, varying from strong or medium strong rocks such as sericite metasandstone, limestone, greywacke, sericite schist through to weak rocks such as metasiltstone, clayey and silty shale and phyllite. The overall rock mass is highly heterogeneous and anisotropic owing to the combined effect of advanced weathering and severe tectonic stressing that gave rise to intense folding and shearing followed by extensional faulting, which resulted in highly weathered rock masses and numerous shear and/or mylonite zones with distinct downgraded engineering properties. This paper is focused on the applicability of the GSI classification system to these highly heterogeneous rock masses and proposes an extension of the GSI system to account for the foliated or laminated weak rocks in the lower range of its applicability.

Hoek-brown failure criterion - 2002 edition

Abstract: The Hoek-Brown failure criterion for rock masses is widely accepted and has been applied in a large number of projects around the world. While, in general, it has been found to be satisfactory, there are some uncertainties and inaccuracies that have made the criterion inconvenient to apply and to incorporate into numerical models and limit equilibrium programs. In particular, the difficulty of finding an acceptable equivalent friction angle and cohesive strength for a given rock mass has been a problem since the publication of the criterion in 1980. This paper resolves all these issues and sets out a recommended sequence of calculations for applying the criterion. An associated Windows program called "RocLab" has been developed to provide a convenient means of solving and plotting the equations presented in this paper.

Gsi: A Geologically Friendly Tool For Rock Mass Strength Estimation

Abstract: This paper presents a review of the estimation of rock mass strength properties through the use of GSI The GSI classification system greatly respects the geological constraints that occur in nature and are reflected in the geological information A discussion is given regarding the ranges of the Geological Strength Index for typical rock masses with specific emphasis to heterogeneous rock masses

The Hoek–Brown Failure Criterion

Abstract: List of Symbols r1 Major principal stress r3 Minor principal stress Co Uniaxial compressive strength mi Hoek–Brown material constant (intact rock) mb Hoek–Brown material constant (rock mass) s Hoek–Brown material constant a Hoek–Brown material constant GSI Geological Strength Index D Disturbance factor To Uniaxial tensile strength r3max Upper limit of confining stress r Coefficient of determination