Publications associées à Use of indentation tests to study the influence of confining stress on rock fragmentation by a TBM cutter

An adaptive phase field approach to 3D internal crack growth in rocks

Tao Xu, Michael Heap, Alexandra Roma Larisa Kushnir

Modeling the 3D internal crack under compression entails complex fracture mechanics (mode I-II-III fracture), resulting in substantial computational costs and challenges in characterizing fracture morphology characterization for Phase Field Method (PFM) si ...

2024

Pore-pressure coefficients for unsaturated soils: generalized effective stress approach

Lyesse Laloui, Alessio Ferrari, Angelica Tuttolomondo

Geotechnical problems with total stress changes occurring rapidly relative to the soil consolidation time can be conveniently addressed using an effective stress-based approach. For saturated states, analytical formulations of pore-pressure coefficients ad ...

CANADIAN SCIENCE PUBLISHING2023

Drained Clay-Pipe Interface Resistance at Low Normal Stresses and Elevated Temperatures

Roba Houhou

Offshore pipelines that transport hydrocarbons under high pressure and high temperature are usually thermally insulated to maintain an elevated temperature and prevent any heat loss to the surroundings. However, the temperatures at the outer-wall of the pi ...

AMER SOC CIVIL ENGINEERS2023

Experimental investigation of dowel action using advanced measurement techniques

Aurelio Muttoni, Marko Pejatovic

Existing shear-cracked structures need to be reliably verified in order to avoid redundant interventions. Code provisions often raise shear safety and/or fatigue life concerns of the reinforcement subjected to stress concentrations due to cyclic dowel acti ...

2022

Investigation of the effect of mineral dissolution on the geomechanical behaviour of geomaterials

Taeheon Kim

Geotechnical engineering scenarios engaged in internal erosion or mineral dissolution were found worldwide, from CO2 sequestration projects to internal erosion of earth dams. Materials subjected to loss of solid phase from their internal fabric vary from s ...

EPFL2022

Effective stress for unsaturated active clays and in-situ effective stress estimation methodology

Angelica Tuttolomondo

The complexity of the mechanics of active clays and, more generally, of geomaterials with clay minerals, under saturated and unsaturated conditions, still provides relevant scientific challenges today. Equally relevant challenges are the understanding of t ...

EPFL2021

Investigating the cracking of plastered stone masonry walls under shear–compression loading

Katrin Beyer, Amir Rezaie, Michele Godio

Cracks are the most important source of information about the damage that occurs to unreinforced masonry piers under seismic actions. To predict the structural state of unreinforced masonry piers after an earthquake, research models have been developed to ...

2021

Anisotropic behaviour of Opalinus Clay through consolidated and drained triaxial testing in saturated conditions

Lyesse Laloui, Alessio Ferrari, Valentina Favero

This paper investigates the anisotropic hydro-mechanical behaviour of Opalinus Clay shale, the host material currently being considered for the construction of a nuclear waste repository in Switzerland. Consolidated and drained triaxial tests on Opalinus C ...

2018

Shear in reinforced concrete without transverse reinforcement : from refined experimental measurements to mechanical models

Francesco Cavagnis

Since the first applications of structural concrete, the shear behaviour of one-way slabs without transverse reinforcement has been largely investigated. Nevertheless, currently in the scientific community there is no general agreement on the mechanisms of ...

EPFL2017

Influence of geometrical imperfections and flaws at welds of steel liners on fatigue behavior of pressure tunnels and shafts in anisotropic rock

Alexandre Jean Pachoud

The recent development of high-strength (HSS) weldable steels has enlarged the range of design alternatives for the optimization of high-head steel-lined pressure tunnels and shafts (SLPT&S) in the hydropower industry. With the liberalization of the Europe ...

EPFL2017

Size effect on punching shear strength: differences and analogies with shear in one-way slabs

Aurelio Muttoni, Miguel Fernández Ruiz

Size effect has been theoretically and experimentally acknowledged as a phenomenon influencing the shear and punching shear strength of concrete structures, with reducing unitary shear strength for increasing member sizes. For members failing in shear, as ...

2016

Elastic and inelastic deformation of fluid-saturated rock

Roman Makhnenko

In situ rock is often saturated with fluid, the presence of which affects both elastic parameters and inelastic deformation processes. Techniques were developed for testing fluid-saturated porous rock under the limiting conditions of drained (long-term), u ...

Royal Soc2016

Determination of minimum CFRP pre-stress levels for fatigue crack prevention in retrofitted metallic beams

Andrin Herwig, Alain Nussbaumer, Elyas Ghafoori, Gary Scott Prinz

The majority of fatigue strengthening studies focus on reducing propagation rates of existing cracks, ignoring the crack initiation stage. Many existing metallic bridge members however do not contain existing cracks, but rather are nearing their design fat ...

Elsevier2015

Rock fragmentation mechanism by TBM cutter and TBM tunnelling under stressed grounds

Lijun Yin

With the advance of technology, TBMs are becoming more versatile and TBM tunnelling has become a common tunnelling method. As TBM tunnelling is a special excavation method depending on the interaction between machine and rock mass under a certain geologica ...

EPFL2013

Characterization of THM Behaviour of Compacted MX-80 Granular Bentonite Using an Advanced Double-wall Triaxial Cell

Lyesse Laloui, Alessio Ferrari, Ali Seiphoori

This paper aims at characterization of thermo-hydro-mechanical behaviour of MX-80 granular bentonite obtained from an innovative double-cell triaxial system. The system has been mainly developed to perform suction controlled tests on unsaturated geomateria ...

2013

Hydro-mechanical behaviour of a volcanic ash

Lyesse Laloui, John Eichenberger, Alessio Ferrari

This paper presents experimental analysis and numerical modelling aimed at improved understanding and prediction of the hydro-mechanical behaviour of volcanic ash at various states of saturation. Results from a comprehensive experimental program are presen ...

Ice Publishing2013

Multi-Scale Approach to Cracking Criteria for Drying Silty Soils

Lyesse Laloui, Mohammad Monfared

Cracking is a most unwanted development in soil structures undergoing periodic drying. Desiccation cracking arises in the apparent absence of external forces. Hence, either an internal, self equilibrated stress pattern resulting from kinematic incompatibil ...

American Society of Civil Engineers2013

Neutron diffraction investigations on residual stresses contributing to the fatigue crack growth in ferritic steel tubular bridges

Claire Acevedo, Alain Nussbaumer

Fatigue crack growth observed in tubular K-joint specimens, typical of tubular bridge structures, always initiates at the chord crown toe locations whether the applied stress range is tensile or compressive. Even though other locations around the weld have ...

Elsevier2012

Numerical study of the effect of confining stress on rock fragmentation by TBM cutters

Hongsu Ma, Lijun Yin

This paper investigates the effect of confining stress on rock fragmentation under TBM cutters by numerical simulation. Firstly, based on the characteristics of the force-penetration curve, the confining stress conditions for TBM tunneling are divided into ...

2011

Micromechanical Study of Rock Fracture and Fragmentation under Dynamic Loads using Discrete Element Method

Tohid Kazerani

The study presented in this thesis aims to numerically explore the micro-mechanisms underlying rock fracture and fragmentation under dynamic loading. The approach adopted is based on the Discrete Element Method (DEM) coupled to the Cohesive Process Zone (C ...

EPFL2011