72867 - Underground Constructions M

Course contents

REQUIREMENTS/PRIOR KNOWLEDGE

A prior knowledge and understanding of Continuum Mechanics, Hydraulics, Soil Mechanics and Applied Geology is required to attend with profit this course.

This knowledge is acquired, as a rule, having passed the following undergraduate courses: Structural Mechanics, Hydraulics, Geotechnics, Geology and Applied Geology.

Fluent spoken and written Italian is a necessary pre-requisite: all lectures and tutorials, and all study material will be in Italian.

 

PROGRAM

1. Rock-mass characterisation for tunnel construction
   • Exploration methods for the in situ characterisation
   • Structural characteristics of the rock-masses
   • Strength, deformability and permeability properties of rocks, discontinuities and rock-masses
   • In situ stress measurement
   • Geomechanical classifications for the rock-masses
   • Definition of the design geotechnical profile

2. Excavation and support methods for underground constructions
   • Drill and blast excavation
   • Excavation with mechanical tools
   • Mechanised tunnelling in soils and rock-masses
   • Support and reinforcement elements
   • Soil improvement methods for tunnel excavation
3. Analysis of the static conditions and interaction with support systems and with the environment
   • State of stress and deformation around a tunnel
   • Analysis of the soil-lining interaction
   • Assessment of the stability conditions
   • Interaction with groundwater surface
   • Surface subsidence and interaction with existing structures
4. General criteria for design and monitoring
   • Monitoring during and after construction
   • Observational method
   • Austrian method and Adeco method
5. Exercises

• Rock material characterisation
• Joint orientation and spacing; stereographic nets
• Geomechanical classifications for the rock-masses
• Strength and deformability of rock material and rock-masses
• In situ tests for the determination of the lithostatic stress state and for the rock-mass characterisation
• Evaluation of the effects induced by the drill and blast excavation
• State of stress and deformation around a circular tunnel in an elastic medium
• State of stress and deformation around a circular tunnel in an elasto-plastic medium
• Characteristic curve method and state of stress in the lining
• Surface subsidence; face stability

Readings/Bibliography

Lecture notes

Teaching methods

Class lessons, class and home exercises

Assessment methods

Oral examination with exercise revision.

During the oral exam the student has to answer to 5 questions on the following points:

1. question on one of the first 5 exercises
2. question on the theoretical aspects covering the first part of the course dedicated to Rock Mechanics
3. question on the excavation and support methods
4. question on one of the last 5 exercises
5. question on the theoretical aspects covering the second part of the course dedicated to Underground Constructions

Higher grades will be awarded to students who demonstrate an organic understanding of the subject, a high ability for critical application, and a clear and concise presentation of the contents. To obtain a passing grade, students are required to at least demonstrate a knowledge of the key concepts of the subject, some ability for critical application, and a comprehensible use of technical language. A failing grade will be awarded if the student shows knowledge gaps in key-concepts of the subject, inappropriate use of language, and/or logic failures in the analysis of the subject.

Teaching tools

• PowerPoint presentations
• visit to the LAGIRN lab of Rock Mechanics
• technical visits at tunnels under construction

Office hours

See the website of Daniela Boldini