Short Courses

GEOLOGY FOR ROCK ENGINEERING PROJECTS

To be confirmed

Instructors

Dr. Philippe Vaskou
Details
Dr. Christophe Vibert
Details

Description

The short course deals first with a recall of basic data of structural geology, presenting the different processes of genesis and resulting characteristics of the main types of rock masses, with emphasize on fractured masses. Thereby is presented how to define a site investigation really adapted to the site conditions.

Then, the methods of analysis of site geotechnical conditions of rock masses are described, including rock mass classification. Interest and limitations of these classifications will be highlighted and illustrated, based on the use of structural geology during mapping.

Obtaining sound data via adapted investigation equipment, as well as the process of data validation will then be exposed, from the rock matrix scale to the rock mass of the site. Particular emphasis is put on the influence of groundwater and groundwater circulation over properties of the rock masses, including how these can be taken into consideration.

The second part of the short course will focus on follow‐up during construction, demonstrating the prime importance of continuous data acquisition during this phase, such as geological/geotechnical mapping of excavation faces. For this purpose, examples will be analysed from real industrial projects. How original design assumptions and design values can be validated and/or updated will also be presented on the basis of case studies.

The end session will describe the monitoring instruments, and how to select the most suitable devices for the validation or updating of design parameters.

A fruitful exchange with the attendees of the short course is expected at the end of the day.



GEOTECHNICAL MONITORING IN CONVENTIONAL TUNNELLING

To be confirmed

Description

Monitoring project

  • Workflow
  • Definition of expected system behaviour
  • Monitoring concept and identification of key observation variables
  • Organisation and management of the monitoring project

Monitoring program

  • Typical monitoring layouts and reading frequency

Monitoring methods

  • Absolute 3D Displacement Monitoring
  • Levelling
  • Extensometers
  • Anchor load cells
  • Tilt meters
  • Hydrostatic levelling systems
  • Borehole Inclinometers     
  • Water level gauges and piezometers
  • Strain gauges
  • Strain meters
  • Vibrating wire sensors
  • Fibre optic sensors
  • Invert probe

Measurements of discontinuity location and orientation

  • Manual structure mapping
  • Digital ground mapping

Evaluation, presentation and interpretation of monitoring data

  • General displacement development
  • 3D displacement monitoring
  • Time - displacement diagram
  • Distance - displacement diagram
  • Assessment of stabilization
  • Displacement development prediction model
  • Displacement vectors in longitudinal and cross section
  • State line (deflection curve) diagrams and trend lines
  • Evaluation of displacement differences or ratios
  • Displacement vector orientation plot in stereonet
  • Stress intensity in a shotcrete lining
  • Surface displacements
  • Extensometers
  • Piezometers
  • Strain Gauges
  • Discontinuity location and orientation

Geotechnical safety management plan

  • Basics
  • Contents
  • Responsibilities
  • Definition of expected system behaviour (target behaviour)
  • Action levels
  • Warning levels
  • Organisation and communication

ISRM 2019