On the variability of squeezing behaviour in tunnelling

Experimental investigations for the modelling of anhydritic swelling claystones

Squeezing ground represents a challenging operating environment as it may slow down or obstruct TBM operation. Due to the geometrical constraints of the equipment, relatively small convergences of 10-20 cm may lead to considerable difficulties in the machine area (sticking of the cutter head, jamming of the shield) or in the back-up area (e.g., jamming of the back-up equipment, inadmissible convergences of the bored profile, damage to the tunnel support). Depending on the number and the length of the critical stretches, squeezing conditions may even call into question the feasibility of a TBM drive. On account of this, and bearing in mind the steady increase in the number of tunnels excavated with TBMs through so-called "difficult ground conditions", the topic investigated in this PhD thesis is of great practical relevance.Based upon case histories reported in the literature, Part I sets out firstly to give an overview of the specific problems of TBM tunnelling under squeezing conditions. Part II presents a computational model which simulates accurately and efficiently the advancing TBM and the installed tunnel support in one single computational step applying the so-called "steady state method". Part III advances a number of theory-based decision aids, which will support rapid, initial assessments to be made of thrust force requirements. Part IV investigates the complex problem of the interaction between the advancing TBM, the consolidating ground and the lining. Emphasis is thereby placed on the effect of the gross advance rate and the effect of ground permeability on shield loading during regular TBM operation (the boring process including short standstills) and during a long standstill.

Forty one years ago, the International Society for Rock Mechanics (ISRM) held its 1st International Congress in Lisbon, Portugal. In July 2007, the 11th ISRM Congress returned to Lisbon, where the Portuguese Geotechnical Society (SPG), the Portuguese National Group of the ISRM, hosted the meeting. The Second Half Century of Rock Mechanics comprises

This book provides a new, necessary and valuable approach to the consideration of risk in underground engineering projects constructed within rock masses. There are Chapters on uncertainty and risk, rock engineering systems, rock fractures and rock stress, the design of a repository for radioactive waste, plus two major case examples relating to th

This book set provides a new, global, updated, thorough, clear, and practical risk-based approach to tunnelling design and construction methods, and discusses detailed examples of solutions applied to relevant case histories. It is organized in three sequential and integrated volumes: Volume 1: Concept – Basic Principles of Design Volume 2: Construction – Methods, Equipment, Tools and Materials Volume 3: Case Histories and Best Practices This book covers all aspects of tunnelling, giving useful and practical information about design (Vol. 1), construction (Vol. 2), and best practices (Vol. 3). It provides the following features and benefits: updated vision on tunnelling design, tools, materials, and construction balanced mix of theory, technology, and applied experience different and harmonized points of view from academics, professionals, and contractors easy consultation in the form of a handbook risk-oriented approach to tunnelling problems. The tunnelling industry is amazingly widespread and increasingly important all over the world, particularly in developing countries. The possible audience of this book are engineers, geologists, designers, constructors, providers, contractors, public and private customers, and, in general, technicians involved in the tunnelling and underground works industry. It is also a suitable source of information for industry professionals, senior undergraduate and graduate students, researchers, and academics.

Tunnelling has become a fragmented process, excessively influenced by lawyers'notions of confrontational contractual bases. This prevents the pooling of skills, essential to the achievement of the promoters' objectives. Tunnelling: Management by Design seeks the reversal of this trend. After a brief historical treatment of selected developments, th

Underground the way to the future was the motto of the World Tunnel Congress 2013 in Geneva, Switzerland. The use of underground space has gained importance during the last years due to the tremendous global urbanization, the high demand on transportation capacities and energy production. All this result in a wider range of use of underground spa