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Rock Mechanics and Rock Engineering

, Volume 52, Issue 1, pp 149–161 | Cite as

DEM Simulation of the Evolution of an Unstable Rock Face: A Modelling Procedure for Back Analysis of Rockslides

  • Francesco CalvettiEmail author
  • Thomas Frenez
  • Mauro Vecchiotti
  • Gianni Piffer
  • Volkmar Mair
  • David Mosna
Original Paper
  • 247 Downloads

Abstract

The evolution of unstable rock slopes is a discontinuous process that is typically characterised by a succession of discrete events, each one giving rise to a new configuration of the rock face. If these events are put in a wider time frame, they can be seen as a local step contributing to the overall process. The advances in recognition systems, such as laser scanning or georadar techniques, allow to build numerical models of higher and higher precision, where the topographic and geostructural configurations may be precisely reconstructed. These improved capabilities open the possibility for defining highly representative numerical models that can be used for back analysis purposes or the design of risk mitigation works. One possible drawback of such approaches is that they superimpose structural and topographic data, whose compatibility is not independent of the mechanical behaviour of the rock mass. In fact, the initial geometry depends on the (usually complex) rock slope history, which has a twofold relationship with the whole set of structural and mechanical features of the rock mass. In order to investigate this point, a series of distinct element analyses of an unstable rock face located in Bolzano province is performed. The model is characterised by a very simple geometry, and slope evolution is studied by adopting the strength reduction technique. Structural and mechanical information is obtained from an extensive in situ survey. The aim of the simulations is to show how a model based on the available geomechanical information and a minimum amount of topographic data can be used to reproduce the main topographic features of the rock slope, and to perform a back analysis of a selected case history.

Keywords

Rock mass Joint behaviour Rock slide Distinct element method Back analysis 

List of Symbols

cj

Joint cohesion (kPa)

tj

Joint tensile strength (kPa)

cr

Intact rock cohesion (MPa)

tr

Intact rock tensile strength (MPa)

cm

Rock mass cohesion (kPa)

Em

Rock mass modulus (GPa)

k

Joint persistence (–)

τ

Joint shear stress (kPa)

\(\sigma _{n}^{\prime }\)

Joint effective normal stress (kPa)

ρ

Intact rock density (kg/m3)

knj

Joint normal stiffness (GPa/m)

ksj

Joint tangential stiffness (GPa/m)

Φj

Joint friction angle (°)

α, αc, αt

Strength reduction coefficients (–)

cjR

Reduced joint cohesion (kPa)

tjR

Reduced joint tensile strength (kPa)

Notes

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Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Dipartimento di Architettura, Ingegneria delle Costruzioni e Ambiente CostruitoPolitecnico di MilanoMilanItaly
  2. 2.INCLINE srlMezzolombardoItaly
  3. 3.Studio di GeologiaLavisItaly
  4. 4.Provincia Bolzano, Ufficio Geologia e prove materialiCardanoItaly

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