Implications for mechanical properties of brittle faults from observations of the Punchbowl fault zone, California

1986 ◽  
Vol 124 (1-2) ◽  
pp. 79-106 ◽  
Author(s):  
F. M. Chester ◽  
J. M. Logan
Keyword(s):  
Mechanical Properties ◽  
Fault Zone

scholarly journals Fracture Mechanical Properties of Damaged and Hydrothermally Altered Rocks, Dixie Valley‐Stillwater Fault Zone, Nevada, USA

2019 ◽  
Vol 124 (4) ◽  
pp. 4069-4090 ◽  
Author(s):  
Owen A. Callahan ◽  
Peter Eichhubl ◽  
Jon E. Olson ◽  
Nicholas C. Davatzes
Keyword(s):  
Mechanical Properties ◽  
Fault Zone ◽  
Dixie Valley

Lateral Variations of Interplate Coupling along the Mexican Subduction Interface: Relationships with Long-Term Morphology and Fault Zone Mechanical Properties

2015 ◽  
Vol 173 (10-11) ◽  
pp. 3467-3486 ◽  
Author(s):  
Baptiste Rousset ◽  
Cécile Lasserre ◽  
Nadaya Cubas ◽  
Shannon Graham ◽  
Mathilde Radiguet ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fault Zone ◽  
Interplate Coupling ◽  
Lateral Variations

Optimization of Tunnel Support Type through Fault Zone

2014 ◽  
Vol 580-583 ◽  
pp. 1184-1187
Author(s):  
Ke Li ◽  
Han Guo
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Reinforced Concrete ◽  
Fault Zone ◽  
Critical Issue ◽  
Surrounding Rock ◽  
The Other ◽  
Support Pressure ◽  
Tunnel Support ◽  
Tunnel Safety

The mechanical properties of tunnel surrounding rock in fault zone is usually quite weak, and the support pressure and displacement are larger than other sections, so the support type in fault zone is a critical issue for tunnel safety. Three types of tunnel support through fault zone were analyzed by finite element method (FEM): ①Reinforced concrete support, ②bolting-shotcreting and reinforced concrete support,③grouting and reinforced concrete support. The result shows that support stress and surrounding rock displacement with grouting and reinforced concrete support is quite smaller than the other support types.

scholarly journals Lateral clay injection into normal faults

GeoArabia ◽  
2003 ◽  
Vol 8 (3) ◽  
pp. 501-522
Author(s):  
Wouter van der Zee ◽  
Janos L. Urai ◽  
Pascal D. Richard
Keyword(s):  
Mechanical Properties ◽  
Fault Zone ◽  
Numerical Models ◽  
Clay Content ◽  
Friction Angle ◽  
Fault Gouge ◽  
Analytical Models ◽  
Normal Faults ◽  
Field Observations ◽  
Injection Process

ABSTRACT The clay content of fault gouge is one of the main factors controlling transport and mechanical properties of a fault zone. This paper addresses the process of lateral clay injection into normal faults, which is one of the many processes contributing to the development of clay smear, and can lead to local enrichment of clay in a fault gouge. We combined field observations with geomechanical models to quantify the parameters leading to lateral clay injection into fault zones. Detailed field study shows that a releasing fault bend in a clay layer is required for clay injection to occur. The clay injection process is often associated with the formation of a branch in the fault and the development of a “squeezing block” which injects the clay into the fault zone. A simple analytical model predicts the onset of clay injection when C = σ'v (1 - sin ϕ) / (2 cos ϕ), where C is cohesion (MPa), σ'v is vertical stress (MPa) and ϕ (°) is friction angle. More detailed analysis using 2-D geomechanical finite element models is in good agreement with the analytical models and allows study of the system at higher fault throw. Results of sandbox models containing layers of an elastoplastic clay analogue also compare well with field observations and numerical models, and show the initiation of the releasing step and the evolution of the clay injection process with increasing fault throw. Using our results it is possible to predict the likelihood of lateral clay injection in the subsurface, in settings like the Gharif formation of the Haushi group of Central and South Oman or the Natih formation of North Oman. This requires an estimation of the mechanical properties of the clays at the time of faulting; data which can be obtained from wireline logs and cuttings. This approach to fault seal analysis emphasizes the mechanical aspects of the clay smear process, in addition to the kinematics which were considered in previous analyses. Its application should lead to improved prediction of fault seal processes in the subsurface.

In-situ petrophysical and geomechanical characterization and 3D modelling of a mature normal fault zone (Goddo fault, Bømlo – Norway)

2020 ◽  
Author(s):  
Alberto Ceccato ◽  
Giulio Viola ◽  
Marco Antonellini ◽  
Giulia Tartaglia ◽  
Eric James Ryan
Keyword(s):  
Mechanical Properties ◽  
Structural Analysis ◽  
Fault Zone ◽  
Normal Fault ◽  
Fault Zones ◽  
Fault Rock ◽  
Fracture Patterns ◽  
Fault Zone Architecture

<p>The detailed characterization of internal fault zone architecture and  petrophysical and geomechanical properties of fault rocks is fundamental to understanding the flow and mechanical behaviour of mature fault zones. The Goddo normal fault (Bømlo – Norway) accommodated c. E-W extension related to North Sea Rifting from Permian to Early Cretaceous times [1]. It represents a good example of a mature, iteratively reactivated and thus long-lived (seismogenic?) fault zone, developed in a pervasively fractured granitoid basement at upper crustal conditions in a regional extensional setting.</p><p>Field characterization of the fault zone’s structural facies and analysis of background fracture patterns in the protolith have been integrated with in-situ petrophysical and geomechanical surveys of the recognized fault zone architectural components. In-situ air-permeability and mechanical directional tests (performed with NER TinyPerm III air-minipermeameter and DRC GeoHammer, L-type Schmidt hammer, respectively) have allowed for the quantification of the permeability tensor and mechanical properties (UCS and elastic modulus) within each brittle structural facies. Mechanical properties measured parallel to fault rock fabric of cataclasite- and gouge-bearing structural facies differ by up to one order of magnitude from those measured perpendicularly to it (~10 MPa vs. 100-200 MPa in UCS, respectively). Accordingly, permeability of cataclasite- and gouge-bearing facies is several orders of magnitude larger when measured parallel to fault-rock fabric than that perpendicular to it (10<sup>-0</sup>-10<sup>-1</sup> D vs. 10<sup>-2</sup>-10<sup>-3</sup> D, respectively). Virtual outcrop models (VOMs) of the fault zone were obtained from high-resolution UAV-photogrammetry. Field measurements of fracture orientations were used for calibration of the VOMs to construct a statistically robust fracture dataset. The results of VOMs structural analysis allowed for the quantification of fracture intensity and geometrical characteristics of mesoscopic fracture patterns within the different domains of the fault zone architecture.</p><p>Results from field, VOMs structural analysis, and in-situ petrophysical investigations have been integrated into a realistic 3D fault zone model with the software 3DMove (Petex). This model can be used to investigate the influence of mesoscopic fracture patterns, related to either the fault zone or the background fracturing, on the hydro-mechanical behaviour of a mature fault zone. In addition, the evolution of the hydro-mechanical properties through time can be assessed by integrating the progressive development of brittle structural facies and fracture sets developed during the incremental strain and stress history into the model. This contribution proposes a geologically-constrained method to quantify the geometry of 3D fault zones, as a possible tool for models to be adopted in stress-strain analysis, hydraulic characterization and in the mechanical analysis of fault zones.</p><p>[1] Viola, G., Scheiber, T., Fredin, O., Zwingmann, H., Margreth, A., & Knies, J. (2016). Deconvoluting complex structural histories archived in brittle fault zones. Nature communications, 7, 13448.</p>

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

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