Publications associées à Rock strength properties of granitic rocks in Yosemite Valley, Yosemite National Park, California

Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment

Roman Pohorsky, Julia Schmale, Athanasios Nenes, Sukriti Kapur, Andrea Baccarini

The Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate and low-photochemical activity), to investigat ...

2024

Fluid flow through microcracked and fractured granitic reservoirs

Marie Estelle Solange Violay, Michael Heap, Lucille Jocelyne Nadine Carbillet

The permeability of crustal rocks and rock-masses dictates the efficiency of hydrothermal circulation and therefore the productivity of geothermal resources. In this study, we find by monitoring P-wave velocity that thermal microcracking in Lanhélin granit ...

2023

Reactivation of variably sealed joints and permeability enhancement in geothermal reservoir rocks

Michael Heap, Alexandra Roma Larisa Kushnir

Hydraulic stimulation of enhanced deep geothermal reservoirs commonly targets pre-existing joint networks with the goal of increasing reservoir permeability. Here, we study the permeability and strength of joint-free and jointed Buntsandstein sandstones fr ...

2023

Elongated hydraulic fracture emerging from layers of alternating fracture toughness

Brice Tanguy Alphonse Lecampion, Carlo Peruzzo

Whether used to enhance the hydrocarbon production from low permeability rocks or to measure the minimum in-situ principal stress in rock formations, height growth of a hydraulic fracture above the formation of interest is a key metric for the design of su ...

2023

Physical characterization of fault rocks within the Opalinus Clay formation

Luis Felipe Orellana Espinoza, Marie Estelle Solange Violay, Christophe Nussbaum

Near-surface disposal of radioactive waste in shales is a promising option to safeguard the population and environment. However, natural faults intersecting these geological formations can potentially affect the long-term isolation of the repositories. Thi ...

Nature Research2022

Experimental plastic reactivation of pseudotachylyte‐filled shear zones

Marie Estelle Solange Violay, François Xavier Thibault Passelègue

Pseudotachylytes are fine‐grained fault rocks that solidify from melt that is produced in fault zones during earthquakes. Exposed sections of natural fault zones reveal evidence of post‐seismic plastic deformation (i.e. reactivation) of pseudotachylyte, wh ...

2021

A new data set of granitic rock strength values from Yosemite Valley, California: applications to rock fall assessment

To explore connections between rock strength and rock falls, we undertook a comprehensive rock mechanics testing program for six granitic rock types in Yosemite Valley (California, USA) where rock falls are a common geomorphic and sometimes hazardous proce ...

2020

Hydraulic stimulation of pre-existing discontinuities in tight rocks

Federico Ciardo

Hydraulic stimulation is an engineering technique whose aim is to enhance the permeability of fractured rock masses at depths ranging from one to five kilometers. It consists in the injection of fluid at sufficiently high pressure in order to shear pre-exi ...

EPFL2020

Evidence of extensive lunar crust formation in impact melt sheets 4,330 Myr ago

Cyril Cayron

Accurately constraining the formation and evolution of the lunar magnesian suite is key to understanding the earliest periods of magmatic crustal building that followed accretion and primordial differentiation of the Moon. However, the origin and evolution ...

2020

Mountain snow: The source of the mother river—Study of multi-scale and multi-physical process of spatio-temporal evolution of snow distribution

Guang Li

Snow is one of the most active elements on the earth, which is an important mass source of polar ice sheets and alpine glaciers, as well as a main supply for the runoff. Its distribution and evolution have a great impact on global hydrological cycle, ecosy ...

2020

Distributed snow and rock temperature modelling in steep rock walls using Alpine3D

Michael Lehning, Nander Wever, Mathias Thierry Pierre Bavay

In this study we modelled the influence of the spatially and temporally heterogeneous snow cover on the surface energy balance and thus on rock temperatures in two rugged, steep rock walls on the Gemsstock ridge in the central Swiss Alps. The heterogeneous ...

Copernicus GmbH2017

Analysis and estimation of gripper TBM performances in highly fractured and faulted rocks

Federica Sandrone, Jian Zhao, Erika Paltrinieri

This paper focuses on performance analysis of Tunnel Boring Machine (in particular gripper TBMs) in highly jointed rock masses and fault zones. In order to investigate possible relationships between these difficult excavation conditions and TBM performance ...

Elsevier2016

Efficient global optimization of reservoir geomechanical parameters based on synthetic aperture radar-derived ground displacements

Francesco Comola

When large volumes of fluids are removed from or injected into underground formations for, e.g., hydrocarbon and water production, CO_2 storage, gas storage, and geothermal energy exploitation, monitoring of surface deformations coupled to numerical modeli ...

Soc Exploration Geophysicists2016

Analysis of TBM tunnelling performance in faulted and highly fractured rocks

Erika Paltrinieri

The thesis focuses on the study of the performance of TBMs in highly jointed and faulted rocks. Despite the great production rates recorded in favourable ground conditions, the TBM advance can be significantly slowed down in limiting geological situations ...

EPFL2015

A hydromechanical approach to assess CO2 injection-induced surface uplift and caprock deflection

Lyesse Laloui, Chao Li

This study focuses on the derivation of a semi-analytical approach for the evaluation of surface uplift and caprock deflection induced by underground injection of CO2. The adopted methodology includes the development of a mathematical model that incorporat ...

2015

A Microstructure-Based Model to Characterize Micromechanical Parameters Controlling Compressive and Tensile Failure in Crystallized Rock

Jian Zhao, Tohid Kazerani

A discrete element model is proposed to examine rock strength and failure. The model is implemented by UDEC which is developed for this purpose. The material is represented as a collection of irregular-sized deformable particles interacting at their cohesi ...

Springer Verlag2014

Coupled Approach to Assess Caprock Deformation Caused by CO2 Injection

Lyesse Laloui, Chao Li

This study focuses on a specific problem related to the caprock deformation induced by the injection of CO2 at depth. The adopted methodology includes the development of a mathematical model that incorporates the deformable behaviour of storage media and t ...

ASCE2014

Study on rock mass boreability by TBM penetration test under different in situ stress conditions

Jian Zhao, Lijun Yin

Rock mass boreability is a comprehensive parameter reflecting the interaction between rock mass and a tunnel boring machine (TBM). Many factors including rock mass conditions, TBM specifications and operation parameters influence rock mass boreability. In ...

Pergamon-Elsevier Science Ltd2014

Quasi-static and dynamic fracture behaviour of rock materials: phenomena and mechanisms

Jian Zhao, Qianbing Zhang

An experimental investigation is conducted to study the quasi-static and dynamic fracture behaviour of sedimentary, igneous and metamorphic rocks. The notched semi-circular bending method has been employed to determine fracture parameters over a wide range ...

Springer Verlag2014

Effects of rock mass anisotropy on deformations and stresses around tunnels during excavation

Anton Schleiss

rock mass where the in situ state of stress is uniform. The rock mass was assumed to behave elastically and two cases were examined: whether the rock mass has an isotropic elastic property or not. A two-dimensional plain strain elastic-plastic Jointed Rock ...

2014