Topic
Stress field
About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.
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TL;DR: In this paper, the authors investigate the ultrasonic velocity response of well-characterised low porosity shales from the Officer Basin in Western Australia to both isotropic and anisotropic stress fields and evaluate the velocity response to the changing stress field.
125 citations
TL;DR: In this article, the authors investigated the possible causes of stress deflection in the Cenozoic East African Rift System (EAR) and found that the Shmax direction from the regional N-S direction to a NW-SE trend and foliations are consistently steeply dipping.
124 citations
TL;DR: In this paper, numerical simulations of circular holes under internal hydraulic pressure are carried out to investigate the hydraulic fracture initiation, propagation and breakdown behavior in rocks, and the simulation results suggest that the fracture initiation and propagation, the roughness of the fracture path and the breakdown pressure are influenced considerably by the heterogeneity of rocks.
Abstract: Numerical simulations of circular holes under internal hydraulic pressure are carried out to investigate the hydraulic fracture initiation, propagation and breakdown behavior in rocks. The hydraulic pressure increases at a constant rate. The heterogeneity of the rocks is taken into account in the study by varying the homogeneity index. In addition, the permeability is varied with the states of stress and fracture. The simulations are conducted by using a finite element code, F-RFPA2D, which couples the flow, stress and damage analyses. The simulation results suggest that the fracture initiation and propagation, the roughness of the fracture path and the breakdown pressure are influenced considerably by the heterogeneity of rocks. The hole diameter elongation and the stress field evolution around the fracture tip during the fracture propagation can also provide useful information for the interpretation of the hydraulic fracturing behaviour.
124 citations
TL;DR: In this paper, an analytical model which represents the behavior of a reinforced rock mass near a circular underground opening in a homogeneous, uniform stress field has been developed, which adopts the concepts of elastoplasticity and considers a proper interaction mechanism between the ground and the grouted (or friction) bolts.
Abstract: An analytical model which represents the behaviour of a reinforced rock mass near a circular underground opening in a homogeneous, uniform stress field has been developed. The theory adopts the concepts of elastoplasticity and considers a proper interaction mechanism between the ground and the grouted (or friction) bolts. It highlights the influence of the bolt pattern on the extent of the yield zone and tunnel deformation. A dimensionless parameter is introduced as a design tool which relates the tunnel convergence to the bolt spacing for a given bolt length. This publication contains the derivation of the analytical model and an illustration of the effect of bolts on the stress and displacement field near an opening. Its application to tunnel design is discussed briefly. The verification of the theory by laboratory simulation and field measurements will be presented, in detail, in a future publication.
124 citations
TL;DR: In this article, a microphysically based material model for the dynamic inelastic response of a brittle material is developed, which is compatible with a previously developed ductile fracture model, and can be formulated as an efficient, robust numerical algorithm for use in threedimensional computer codes.
Abstract: A microphysically based material model for the dynamic inelastic response of a brittle material is developed. The progressive loss of strength as well as the post‐failure response of a granular material with friction are included. Crack instability conditions (an inelastic surface in stress space) and inelastic strains are obtained by considering the response of individual microcracks to an applied stress field. The assumptions of material isotropy and an exponential distribution for the crack radius are invoked to provide a tractable formulation. The constitutive model requires a minimal number of physical parameters, is compatible with a previously developed ductile fracture model [J. Appl. Phys. 64, 6699 (1988)] that utilizes inelastic surfaces, and can be formulated as an efficient, robust numerical algorithm for use in three‐dimensional computer codes. The material model is implemented into a Lagrangian computer formulation for the demonstration of material response to dynamic loading conditions. Comparisons with one‐dimensional, uniaxial impact experiments are provided.
124 citations