Vincent Labiouse

University of Applied Sciences and Arts Western Switzerland · School of Engineering & Architecture Fribourg

The second generation of Eurocode 7 includes both soil and rock. In addition to the current practice of ground engineering, this document aims at incorporating rock engineering, improving the ease of use, the harmonization of regulations and covering new developments. This paper provides an overview of some of the significant changes to Eurocode 7...

The second generation of Eurocode 7 aims at covering ground, including both soil and rock. Current practice of ground engineering forms the basis, and the aim is to include rock engineering, improving ease of use, harmonization of regulations, and covering new developments. This paper deals with EN 1997 part 1 addressing the general rules of geotec...

Most rock fall hazard zoning methodologies are currently based on trajectory modelling, usually performed along 2D slope profiles. For many topographic configurations, this approach cannot provide a realistic description of the way rock fall trajectories and, ultimately, hazard are spatially distributed all over a slope. This paper presents a new m...

Tunnel excavation in Boom Clay formation, Belgium, highlighted an anisotropic behavior related to its bedding planes. Hollow cylinder tests mimicking tunnel excavation under laboratory conditions confirmed the isotropic convergence of samples cored perpendicular to the bedding and the anisotropic behavior of samples cored parallel to the bedding. T...

The Structural Eurocodes (EN 199x) are a suite of European standards for the design of buildings and civil engineering works, published in 2006 by the European Committee for Standardization (CEN) and with implementation starting in 2010. EN 1990 sets the basis of structural design, with the other Eurocodes dealing with different materials and speci...

Adopting effective maintenance strategies for transportation infrastructures requires good prediction of their long-term behaviour. For planning interventions without affecting the entire network’s capacity, tunnels in particular require a good overview of expected problems. G.I.S. tools are helpful for managing transportation networks since they a...

In order to investigate the causes of underground collapse and aid the development of prevention strategies, we conducted a detailed study of the physico-mechanical behaviour and ageing of chalk in underground quarries in the Parisian Basin, France. Core samples were drilled horizontally from pillars at two sites: the Saint-Martin-le-Nœud undergrou...

Analytical solutions for tunnel design are widely used in practical engineering, as they allow a quick analysis of design issues such as estimation of support requirement. In recent years, several papers analyzing the behavior of rock masses that obey the conventional or generalized Hoek–Brown criterion have been published. This article presents a...

Landslide continuum dynamic models have improved considerably in the last years, but a consensus on the best method of calibrating the input resistance parameter values for predictive analyses has not yet emerged. In the present paper, numerical simulations of a series of laboratory experiments performed at the Laboratory for Rock Mechanics of the...

Chalk rocks have been used for centuries as a strong building material and for the production of lime. The shallow underground room-and-pillar quarries where the chalk was extracted are now abandoned and endure the effects of time and weathering, increasing their risk of collapse. The risk of instability, involving natural or anthropic underground...

A series of triaxial laboratory experiments are performed on thick-walled hollow cylindrical samples of boom clay. The aim of this testing program is to better understand the anisotropic deformation during the excavation. The testing conditions are similar to those to be experienced by host rocks around disposal galleries for radioactive waste. X-r...

Invited lecture La première version des normes SIA est entrée en vigueur en 2003. La pratique a montré que l’eau souterraine n’était pas toujours considérée de façon adéquate lors de l’étude et la réalisation de projets, avec parfois comme conséquence des instabilités hydrauliques. Bien que les normes ne puissent à elles seules résoudre le problème...

Rock fall hazard assessment and zoning are very important for an appropriate land use planning in mountainous areas. However, they are complex topics, and current methodologies adopted for producing zoning maps do not provide satisfactory results, due to assumptions and uncertainties involved in hazard assessment. This paper presents an application...

Rock fall hazard zoning is a challenging yet necessary task to be accomplished for planning an appropriate land use in mountainous areas. Methodologies currently adopted for elaborating zoning maps do not provide satisfactory results though, due to uncertainties and related assumptions characterising hazard assessment. The new Cadanav methodology,...

In the present work, an attempt has been achieved to describe the effects of ageing and of water on the hydro-mechanical behaviour of chalks from underground quarries of northern Parisian basin. Physical and mechanical properties were obtained as a function of distances from the pillar face (horizontal core drillings, from the wall to the centre) a...

Keynote Lecture RSS 2014 Although rock instabilities constitute a threat to human lives and settlements all over the world, methodologies for assessing and zoning rockfall hazards for urban development planning are far from being standardised. After presentation of the general background and classification of existing approaches, the report discuss...

In the context of nuclear waste disposal in clay formations, laboratory experiments were performed to study at reduced scale the excavation damaged zone (EDZ) induced by the construction of galleries in the Boom clay formation. For this purpose, thick-walled hollow cylindrical samples were subjected (after recovery of in situ stress conditions) to...

Boom Clay is extensively studied as a potential candidate to host underground nuclear waste disposal in Belgium. To guarantee the safety of such a disposal, the mechanical behaviour of the clay during gallery excavation must be properly predicted. In that purpose, a hollow cylinder experiment on Boom Clay has been designed to reproduce, in a small-...

In the context of nuclear waste disposal in clay formations, laboratory and in situ simulation experiments were performed to study at reduced scale the excavation damaged zone (EDZ) around tunnels in the indurated Opalinus Clay at Mont Terri, Switzerland. In the laboratory, thick-walled hollow cylindrical specimens were subjected to a mechanical un...

A proper evaluation of the perturbations of the host rock induced by the excavation and the emplacement of exothermic wastes is essential for the assessment of the long-term safety of high-level radioactive waste disposals in clay formations. The impact of the thermal transient on the evolution of the damaged zone (DZ) has been explored in the Euro...

This section reviews the current methodologies that are used for the assessment of the rockfall susceptibility, hazard and risk. Emphasis is given on quantitative methods although qualitative ones are also discussed. The different methodologies are presented with respect to their application scales (regional, local or site-specific). Highlight is g...

In Switzerland, many inhabitants and infrastructures are subject to natural hazards like rockfalls in mountain areas. In order to prevent unconsidered risks, it is essential to investigate hazardous phenomena and plan land-use restrictions and/or mitigation measures. In the present study, the Alpine villages of Lourtier and Les Morgnes (Val de Bagn...

Rockfall hazard assessment without the use of rockfall trajectory and runout zone models is unthinkable in the 21st century. Such rockfall models have existed since the sixties, but nowadays an almost confusing palette of rockfall trajectory and runout zone models in 2- and 3-D exists. Each of those adapted to specific rockfall problems. This chapt...

Laboratory experiments which consist of releasing dry rigid non-cohesive grains or small bricks on an unconfined chute have been designed to investigate rock avalanche propagation mechanisms and to identify parameters influencing their deposit characteristics. Factors such as volume, fall height, basal friction angle, material used, structure of th...

No abstract available.

Rock avalanches are studied at the Laboratory for Rock Mechanics of EPF Lausanne by means of unconstrained flow experiments of dry granular material. Tests aim at studying the influence of different parameters on the propagation and deposition mechanisms as well as on the characteristics of the final deposit. The existing measurement system, based...

This paper deals with the theoretical-numerical and experimental analysis of dry rock avalanches moving down a chute. Depth-averaged field equations of balance of mass and momentum as prescribed by Savage and Hutter (1991) are implemented in the RASH3D code. They describe the temporal evolution of the depth averaged velocity and the distribution of...

Sound evaluation of the failure process around galleries is an important item for the stability and safety of underground excavations. In many European Countries, clay geological formations are selected as potential host rock for nuclear waste disposal, e.g., Boom Clay (a plastic clay) and Opalinus clay (an indurated clay) are promising formations...

Rockfall is an extremely rapid process involving long travel distances. Due to these features, when an event occurs, the ability to take evasive action is practically zero and, thus, the risk of injury or loss of life is high. Damage to buildings and infrastructure is quite likely. In many cases, therefore, suitable protection measures are necessar...

Rockfall is an extremely rapid process involving long travel distances. Due to these features, when an event occurs, the ability to take evasive action is practically zero and, thus, the risk of injury or loss of life is high. Damage to buildings and infrastructure is quite likely. In many cases, therefore, suitable protection measures are necessar...

This paper investigates the load-bearing capacity of a perfectly smooth retaining wall laterally supported at both ends assuming that the wall fails by the development of three plastic hinges. The study considers the case of a cohesionless elastic–perfectly plastic backfill with a Mohr–Coulomb yield criterion and an associative flow rule in drained...

Rockfall propagation areas can be determined using a simple geometric rule known as shadow angle or energy line method based on a simple Coulomb frictional model implemented in the CONEFALL computer program. Runout zones are estimated from a digital terrain model (DTM) and a grid file containing the cells representing rockfall potential source area...

In order to evaluate the general conditions (i.e. safety, serviceability and durability) of tunnels, a detailed analysis of the lining structure and surrounding rock mass is required. During the service life of the tunnel, regular survey activities should be performed to check the tunnel conditions and regular conservation practices are necessary t...

X-ray computed tomography (XRCT) can reconstruct, in a nondestructive way and in three-dimension, the distribution of densities within opaque materials. Consequently, it provides an effective possibility to characterize the inner content of rock core samples and, in particular their alteration products sensu lato which generally appear less dense t...

Rock falls represent a serious threat to communities living in mountainous areas in several European countries, and their potential hazard must be taken into account for an appropriate land-use planning and for establishing risk reduction measures. European-wide standard methods for hazard evaluation and mapping would be a very important step towar...

European-wide standard methodologies for rock fall hazard assessment and mapping would constitute a very important step towards more transparent and reproducible procedures used for these purposes, and would provide as well a higher uniformity in land use planning and risk management. However, the current situation in Europe shows the opposite tend...

Landslide hazard mapping aims at providing very useful information for urban planning and for risk analysis. Though landslide risks represent a common threat to human lives and properties worldwide, the procedures applied for hazard and risk assessment are far from being standardised, due to the diverse approaches adopted in each country. In this p...

Several authors have resorted to physical modelling in the field of rock avalanches. After a review of some of these works, the present paper describes tests carried out at the Ecole Polytechnique Fédérale de Lausanne. The main goal of these experiments, i.e. unconstrained flows of gravel and blocks, is to better understand propagation mechanisms a...

The Proceedings of EUROCK 2010 is a collection of 6 keynotes and 193 technical papers accepted by the symposium. As an annual European regional event of the International Society for Rock Mechanics (ISRM), EUROCK has been a major exchange and discussion platform for the international rock mechanics community. Rock mechanics in Europe has been under...

The paper focuses on the delayed behaviour of marls induced by a change in stress state and by the effect of water. Seven experiments were conducted in oedometric cells on marl from the Arbus tunnel (France). The samples were subjected to a single loading step (i.e one-stage creep test) or to successive loading steps (i.e. multi-stage creep test) f...

Four gravel unconstrained flow experiments were modelled with the DAN-3D and RASH-3D codes. Both the codes, based on continuum mechanics, were developed for the propagation of rapid landslides, like rock avalanches. The codes were at first run to back-calculate the dynamic basal friction angle (frictional rheology) in order to model the runout of o...

Laboratory experiments carried out at the LMR-EPFL on thick-walled hollow cylindrical samples aim at modelling at small-scale conditions similar to those that will be experienced by host rocks around disposal galleries for heat emitting radioactive waste. The paper presents results on a Boom Clay sample cored parallel to the bedding planes and subj...

Basic principles of living with natural risks are established according to the experience of each country in facing this problem. The strategies adopted for evaluating rockfall hazards and for reducing the potential risk they represent may therefore lead to the development of quite different guidelines. In fact, despite the approach defined for thi...

Since both lining structure and rock mass exhibit delayed behaviour, tunnel equilibrium conditions evolve with time. After discussing existing work done on different aspects of long-term tunnel behaviour, the aim of this paper is to “understand” the influence of rock mass and lining degradations on the long-term stability conditions of the tunnel b...

In the framework of rockfall trajectory modelling, the bouncing phenomenon occurring when a rock block impacts with the slope surface is the most difficult to predict, owing to its complexity and its very limited understanding. To date, the rebound is commonly quantified by means of two coefficients of restitution estimated from a rough description...

Laboratory experiments play an important role in improving the modelling of rock avalanches since they contribute to a better understanding of the mechanisms that characterise propagation and to identifying parameters influencing velocity and deposit characteristics. Tests analysed in this paper consist of unconstrained flows of gravel and small bl...

Within the framework of the TIMODAZ project laboratory and in-situ experiments have been performed to study the failure processes around tunnels in laminated clay rich sedimentary rocks at reduced scale. The fracture patterns observed in the hollow cylinder laboratory experiment and in the borehole-scale in-situ experiment show great similarity. In...

The SELFRAC project aimed to study the fractures within the Excavation Damaged Zone (EDZ) around galleries in the Boom clay and Opalinus clay formations and their possible sealing/healing with time. Tests carried out at LMR-EPFL aimed at quantifying on the same sample the increase in permeability induced by a localised crack, and subsequently the p...

Among the different natural hazards, rockfall has an important place even though other natural hazards could affect more people or have greater consequences. The phenomenon may be further classified according to the size of the largest blocks and the total rock mass involved. The risk management procedure can be divided into (i) hazard identificati...

Rock fall hazard assessment and hazard mapping are essential for the risk management of vulnerable areas. This paper analyses some issues concerning fragmental rock fall hazard mapping methodologies. Two Swiss approaches based on rock fall trajectory simulations results are presented. An application to a site in Switzerland emphasises the differenc...

During the crossing of brittle rock formations at the Lötschberg base tunnel, failure phenomena have been observed both at the tunnel face and at the walls. A detailed analysis has been undertaken to explain these behaviours, based on the recent developments of Canadian research on brittle failure mechanisms. At the tunnel walls, a very good agreem...

Technical difficulties associated with excavation works in tectonized geological settings are frequent. They comprise instantaneous and/or deferential convergence, sudden collapse of the walls and/or roof of the gallery, outpouring of fault-filling materials and water inflows. These phenomena have a negative impact on the construction sites as well...

The need to cope with rockfall hazard and risk led many countries to adopt proper strategies for hazard mapping and risk management, based on their own social and political constraints. The experience of every single country in facing this challenge provides useful information and possible approaches to evaluate rockfall hazard and risk. More, with...

The aim of the TIMODAZ project is to investigate the effect of thermal changes on the excavation damaged zone (EDZ) around nuclear deep disposals in clay-based geological formations. In the framework of WP5.2 of this project, it is intended to develop constitutive models and numerical tools reproducing the thermo-hydro-mechanical (THM) evolution of...

this paper illustrates the application of a new optical measuring technique, the fringe projection method, to obtain the final deposit thickness of unconstrained granular flow experiments. This allows retrieving the position of the centre of mass, important information for the study of rock avalanche propagation. The fringe projection method consis...

This paper illustrates the results of a collaboration born among the authors, in the framework of the INTERREG IIIA ‘‘Rockslidetec’’ project, with the aim of studying rock avalanche propagation by means of physical and numerical modelling. The EPFL rock mechanics laboratory has carried out an experimental campaign. Tests consist in releasing uncons...

The paper presents first considerations about methodologies for local hazard mapping related to rockfalls. This work is being currently carried out at the Swiss Federal Institute of Technology of Lausanne (EPFL), and it concerns the ESR8 research position within the framework of the Mountain Risks project (Marie Curie Research Training Network, fun...

This paper presents an experimental study of rock avalanches run-out and propagation carried out with a small-scale physical model at the EPFL Rock Mechanics Laboratory. Fall height, volume, releasing geometry and materials used for testing have been varied and their influence on deposit characteristics (such as length, width, height and morphology...

Collect and store information, after tunnel construction and during operation, may help the tunnel owner to follow the structure evolution with time. Long term serviceability and behaviour can be better evaluated by taking into consideration all tunnel features such as geometry, geological and hydrogeological conditions, age, construction techniqu...

La recherche effectuée sur les tranchées couvertes, ou tunnels exécutés à ciel ouvert, apporte une contribution théorique à la compréhension du comportement de ces ouvrages jusqu’à l’état limite ultime. Une méthode simplifiée inspirée de la méthode convergence-confinement est développée puis appliquée à plusieurs cas représentatifs. Cette méthode,...

The communication shows an alternative for introducing soil-structure interaction in the analysis of cut-and-cover tunnels. An uncoupled method is illustrated through two examples representative of the situations found in practice. The main features of each case are presented and compared. The ultimate limit state behavior and the ductility of thes...

The communication shows an alternative for introducing soil-structure interaction in the analysis of cut-and-cover tunnels. An uncoupled method is illustrated through two examples representative of the situations found in practice. The main features of each case are presented and compared. The ultimate limit state behavior and the ductility of thes...

Recent excavation works through Switzerland and surrounding countries were confronted with difficult geological settings that have in particular case produced delays in the projects realization as well as an increased hazard for the staff working underground. A couple of these shallow to deep tunnelling projects were investigated in the framework o...

L’Eurocode 7 contribue à l’identification d’un langage commun à la profession géotechnique, au dialogue indispensable entre géotechniciens et ingénieurs de structure, et à la promotion d’une assurance-qualité unifiée à l’échelle européenne. La SIA 267, qui est amenée à remplir à terme le rôle de document national d’application, s’inscrit dans cet e...

Rockfall hazard zoning is usually achieved using a qualitative estimate of hazard, and not an absolute scale. In Switzerland, danger maps, which correspond to a hazard zoning depending on the intensity of the considered phenomenon (e.g. kinetic energy for rockfalls), are replacing hazard maps. Basically, the danger grows with the mean frequency and...