Rock mechanics and engineering

Jaeger, Christophe

doi:10.1017/cbo9780511735349.011

Cited by 19 publications

(33 citation statements)

References 3 publications

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“…We used large rock specimens with a statistical distribution of > 100 fissures, cracks and cleavages in a sample to cope with natural bedrock heterogeneity (Akimov et al, 1973;Jaeger, 2009;Matsuoka and Murton, 2008). All samples were immersed in water under atmospheric conditions until full saturation indicated by a constant weight was achieved (W s ).…”

Section: Methodsmentioning

confidence: 99%

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

Draebing

Krautblatter

2012

The Cryosphere

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Abstract. P-wave refraction seismics is a key method in permafrost research but its applicability to low-porosity rocks, which constitute alpine rock walls, has been denied in prior studies. These studies explain p-wave velocity changes in freezing rocks exclusively due to changing velocities of pore infill, i.e. water, air and ice. In existing models, no significant velocity increase is expected for low-porosity bedrock. We postulate, that mixing laws apply for high-porosity rocks, but freezing in confined space in low-porosity bedrock also alters physical rock matrix properties. In the laboratory, we measured p-wave velocities of 22 decimetre-large lowporosity (< 10 %) metamorphic, magmatic and sedimentary rock samples from permafrost sites with a natural texture (> 100 micro-fissures) from 25 • C to −15 • C in 0.3 • C increments close to the freezing point. When freezing, pwave velocity increases by 11-166 % perpendicular to cleavage/bedding and equivalent to a matrix velocity increase from 11-200 % coincident to an anisotropy decrease in most samples. The expansion of rigid bedrock upon freezing is restricted and ice pressure will increase matrix velocity and decrease anisotropy while changing velocities of the pore infill are insignificant. Here, we present a modified Timur's twophase-equation implementing changes in matrix velocity dependent on lithology and demonstrate the general applicability of refraction seismics to differentiate frozen and unfrozen low-porosity bedrock.

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Section: Methodsmentioning

confidence: 99%

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

Draebing

Krautblatter

2012

The Cryosphere

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“…The Coulomb failure criterion is commonly used to identify failure in soil and rock mechanics (Jaeger 1972;Brady and Brown 1993;King et al 1994). …”

Section: Coulomb Stress Failurementioning

confidence: 99%

Horizontal respect distance for hydraulic fracturing in the vicinity of existing faults in deep geological reservoirs: a review and modelling study

Westwood

Toon

Styles

et al. 2017

Geomech. Geophys. Geo-energ. Geo-resour.

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Hydraulic fracturing is widely used in the petroleum industry to enhance oil and gas production, especially for the extraction of shale gas from unconventional reservoirs. A good understanding of the vertical distance which should be preserved between hydraulic stimulation and overlying aquifers (potable water) has been demonstrated as being greater than 600 m (2000 feet). However, the effective application of this technique depends on many factors; one of particular importance is the influence of the fracturing process on pre-existing fractures and faults in the reservoir, which, however, to date, has had little analysis. Specifically, the identification of the required respect distance which must be maintained between the hydraulic fracturing location and pre-existing faults is of paramount importance in minimizing the risk of felt, induced seismicity. This must be an important consideration for setting the guidelines for operational procedures by legislative authorities. We investigate the respect distance using a Monte Carlo approach, generating fifty discrete fracture networks for each of three fracture intensities, on which a hydraulic fracturing simulation is run, using FracMan Ò . The Coulomb stress change of the rock surrounding the simulated injection stage is calculated for three weighted source mechanisms combining inflation, strike-slip and reverse. The lateral respect distance is obtained using values from literature of the amount of stress required to induce movement on a pre-existing fault. We find that the lateral respect distance is dependent on fracture intensity and the failure threshold. However, the weighting of the source mechanism has limited effect on the lateral respect distance.

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“…e original equilibrium state of stress is disrupted due to the excavation of underground engineering, which causes the stress to be redistributed [1][2][3]. We know that the deformation of surrounding rock is the result of excavation disturbance and stress release.…”

Section: Introductionmentioning

confidence: 99%

Analytical Solution of Tunnel Surrounding Rock for Stress and Displacement Based on Lade–Duncan Criterion

Zhu

Yang

Gao

et al. 2018

Advances in Civil Engineering

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e deformation and failure of tunnel surrounding rock is the result of tunnel excavation disturbance and rock stress release. When the local stress of surrounding rock exceeds the elastic limit of rock mass, the plastic analysis of surrounding rock must be carried out to judge the stability of tunnel. In this study, the Lade-Duncan yield criterion is used to calculate the analytic solutions for the surrounding rock in a tunnel, and the radius and displacement of the plastic zone are deduced using an equilibrium equation.e plastic zone radius and displacement based on Lade-Duncan criterion and Mohr-Coulomb criterion were compared by using single-factor analysis method under the different internal friction angles, in situ stresses, and support resistances. e results show that the solutions of the radius and displacement of plastic zone calculated by the Lade-Duncan criterion are close to those of Mohr-Coulomb criterion under the high internal friction angle and support resistance or low in situ rock stress; however, the radius and displacement of the plastic zone calculated by the Lade-Duncan criterion are larger under normal circumstances, and the Lade-Duncan criterion is more applicable to the stability analysis of the surrounding rock in a tunnel.

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Rock mechanics and engineering

Cited by 19 publications

References 3 publications

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

Horizontal respect distance for hydraulic fracturing in the vicinity of existing faults in deep geological reservoirs: a review and modelling study

Analytical Solution of Tunnel Surrounding Rock for Stress and Displacement Based on Lade–Duncan Criterion

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