Normal Stress Changes Research Articles

Fiber-Matrix Interaction and Fiber Orientation in Simple Shearing of Fibrous Soft Tissues

Fiber-reinforcement is a common feature of many soft biological tissues. The response of fibrous biotissues to applied shear is thus of considerable current interest. We consider here the fundamental deformation of simple shear within the framework of transversely isotropic incompressible hyperelastic materials for fiber-reinforced specimens with a single family of parallel fibers oriented at a general angle to the direction of shear. It is well known that the normal stress effect characteristic of nonlinear elasticity plays a crucial role in maintaining an homogeneous deformation state in the bulk of the specimen. Here we investigate the effects of fiber-matrix interaction on the shear and lateral normal stresses. The inclusion of fiber-matrix interaction stiffens the shear stress response. As regards the normal stress, it is shown that the confining normal traction that needs to be applied to the top and bottom faces of a block in order to maintain simple shear can be compressive or tensile depending on the degree of anisotropy, fiber-matrix interaction and on the angle of orientation of the fibers. In the absence of such an applied traction, an unconfined sample tends to bulge outwards or contract inwards perpendicular to the direction of shear so that one has the possibility of both a positive or negative Poynting effect. It is shown that the fiber-matrix interaction enhances both the positive and negative Poynting effects. The results are illustrated using experimental data obtained by other authors for porcine brain white matter. In particular, it is shown that, for sufficiently small angles of orientation, a transition amount of shear exists at which the normal stress changes character from tensile to compressive with increasing amount of shear. An increase in the degree of fiber-matrix interaction enlarges the range of orientation angles for which this transition can occur and decreases the transition amount of shear. These transition amounts of shear are well within the physiological strain regime. The results obtained here are relevant to the development of accurate shear test protocols for the determination of constitutive properties of fibrous biological soft tissues.

Stress changes associated with the significant first subevent of the 2008 Wenchuan earthquake and implications for the rupture behavior transition

The rupture process of the Wenchuan earthquake demonstrated a transition from thrust-dominated slip to northeastward strike-slip motion along the Longmen Shan Fault Zone. The initial stress has been reported as playing a critical role in this process; however, the stress changes, especially those caused by the significant first subevent of the Wenchuan earthquake are not well understood. Here, we employ a three-dimensional finite element model of the Sichuan-Yunnan region to analyze the stress change caused by the significant first subevent and explore the possible influence on the following ruptures. The results indicate that the auxiliary maximum principal compressive stress (SH) associated with the significant first subevent was horizontal and that the auxiliary stress regime was SH>Sh>Sv, supporting the ongoing regional thrust motion near the southwestern segment of the rupture plane. However, in the northeastern segment, the auxiliary stress regime transitioned to SH>Sv>Sh, demonstrating that the stress changes promoted the transition of the rupture behavior from predominantly thrust motion in the southwest to right-lateral strike-slip motion in the northeastern segment, which was also supported by the dominant shear stress change and the subtle normal stress change along the fault plane in the northeastern segment. In addition, our modeled results also indicate that the orientation of the maximum principal compressive stress changed from SEE to northeastward NEE along the strike of Longmen Shan Fault Zone. This anticlockwise rotation hastened the rupture behavior transition, suggesting that both the initial stress and the stress changes associated with the first subevent jointly controlled the following northeastward rupture of the Mw7.9 Wenchuan earthquake.

НЕЛІНІЙНА ДЕФОРМАЦІЙНО-СИЛОВА МОДЕЛЬ БЕТОННОГО СТЕРЖНЯ З НЕМЕТАЛЕВОЮ КОМПОЗИТНОЮ АРМАТУРОЮ У ЗАГАЛЬНОМУ ВИПАДКУ НАПРУЖЕНОГО СТАНУ

The article discusses a nonlinear deformation-force model of a concrete bar structure with a non-metallic composite reinforcement (NKA-FRP) in the general case of a stressed state, when all four internal force factors from an external load (namely, bending and twisting moments, transverse and longitudinal forces). A sufficiently deep and meaningful analysis of well-known studies on the selected topic is given. It has been established that the proposed nonlinear deformation-force model of a bar structure with FRP in the general case of a stressed state can be practically useful due to the possibility of its application in the design or reinforcement of beams, girders, columns and elements of rosette trusses of rectangular cross-section, which are operated under aggressive environmental conditions. This model can also be used to check the bearing capacity of existing FRP concrete bar structures, which operate not only under the influence of an aggressive environment, but also under conditions of a complex stress-strain state. In the course of the research, an algorithm was developed for determining the bearing capacity of the design section of a concrete rod with FRP under its complex stress state. General physical relations for the design section are given in the form of a stiffness matrix. The algorithm for calculating a concrete bar with FRP consists of a block for inputting the initial data, the main part, auxiliary subroutines for checking the conditions for increasing the load vector and depletion of the bearing capacity, as well as a block for printing the calculation results. At each stage of a simple static stepwise increasing load, the calculation is carried out by performing a certain number of iterations until the accuracy of determining all components of the deformation vector satisfies a certain predetermined value. The features and patterns of changes in normal and tangential stresses, generalized linear and angular deformations, as well as the equations of equilibrium of a concrete bar with FRP, which operates under the influence of an aggressive environment under conditions of a complex stress state, are also considered.

Numerical analysis of the influence of the number of waste canister in borehole on the temperature, stress, and displacement in the near field of the high-level waste repository

Safe disposal of high-level waste is a challenging problem facing the scientific, technological, and engineering communities. The actual high-level waste disposal is closely related to the number of waste canisters in a single borehole. The influence of the number of waste canisters in a single borehole on the near-field temperature, stress, and displacement of the repository is directly related to the safety and cost of waste disposal. In this paper, based on the conceptual model of the high-level waste repository, the influence of the number of waste canisters in a single vertical borehole on the near-field temperature, stress, and displacement of the high-level waste repository was calculated and analyzed by using the 3DEC program. The results show that as the number of waste canisters in a single borehole increases, its heat release capacity is enhanced, and the temperature in the same area near the repository increases gradually; the temperature gradient increases gradually. The more waste canisters in a single borehole, the higher the temperature of the observation point near the same location of the repository (about 30°C), the temperature difference is getting larger and larger, and the average increase of temperature difference at observation point is about 8.1°C. The change of normal stress at the observation point is obvious when the waste canister releases heat for about 0–1 year; after that, the compressive stress decreased slightly, and then the stress and time curve was basically horizontal; the stress difference is getting larger and larger; the average increase of stress difference is about 0.0545MPa.The general trend of observation point displacement is that when the waste canister releases heat for about 0–1 year, displacement increases greatly, and then displacement increases less and presents a linear distribution trend; the displacement difference is getting larger and larger; the average increase of displacement difference is about 0.00034m. The thermal superposition effect of waste canisters added in a single borehole in engineering design cannot be ignored, and it showed that attention should be paid to the number of waste canisters in the disposal pit.

To the forecast of martensitic transformation development during sink drawing of austenitic steel pipes

The work aim is the mathematical modeling of the austenitic steel pipes sink drawing process to establish the effect of the pipe wall thickness on the material stress-strain state and to predict the martensitic transformation development. The drawing process was simulated for thin-walled and thick-walled pipes by the finite element method using the DEFORM-2D software package. There are determined the shape change and deformations distribution, the deformations intensity and the average normal stress for seven variants of pipes with different wall thickness ratios and diameter are determined. Distribution patterns for two extreme variants are shown. The difference is shown in the stress state at the drawing process of thin-walled and thick-walled pipes. The change in the average normal stress in time t of a particle passage through the deformation zone for the outer and the inner surfaces for a thin-walled and extra thick-walled pipe is given. In either case, the compression stresses up to –400 MPa for the inner surface and tensile stresses for the outer surface up to +200 MPa are prevail at the entrance to the deformation zone. Inside the deformation zone, a thin-walled pipe is characterized by the presence of approximately equal compressive stresses both on the outer surface and on the inner one. However, the stresses are close to zero outside and reach –600 MPa inside for a thick-walled pipe. The deformation zone numerical simulation in the sink drawing made of austenitic steel showed that there are differences in the stress-strain state in the case of processing thin-walled and thick-walled pipes. The performed calculations and comparison with the literature data on the stress state influence on the cold martensitic transformation process made it possible to predict the development of this transformation in the drawing process. It was revealed that during thin-walled pipes drawing process are created more favorable conditions for the phase transition development.This work was performed with partial financial support of Resolution No. 211 of the Government of the Russian Federation, contract No. 02.A03.21.

MATHEMATICAL MODEL OF THE DYNAMICS DISPERSED MEDIA IN THE SHAPING PROCESSES BILLETS OF POWDER METALLURGY

A mathematical model has been developed for changing the dynamics of the movement of a dispersed medium in vibro-impact technological processes of shaping of powder metallurgy blanks. On the basis of the problem of two-dimensional dynamic interaction of dispersed particles of powder metal of a spacer dispersed medium, the obtained differential equation in partial derivatives under various boundary conditions. This equation describes the state of the local area of the dispersed medium. In it, the powder material of the workpiece passes from the concentrated dynamic force to the excitation phase. A partial differential equation is obtained. It describes the change in normal stress during vibrations of a dispersed medium during vibration compaction of a workpiece in powder metallurgy.

Shear fracture energies of stiff clays and shales

Fracture mechanics analysis of shear band propagation requires knowledge of the material’s shear fracture energy and its related properties such as the characteristic slip displacement. Yet these properties of stiff clays and shales have not been investigated systematically. This work characterizes and analyzes the shear fracture energies and characteristic slip displacements of various stiff clays and shales based on their triaxial compression data from the literature. A methodology originally developed for hard rocks was adopted for this purpose. Results show that the shear fracture energies of stiff clays and shales generally increase with the effective normal stress on the slip plane, varying by orders of magnitude—approximately from $$4\times 10^{1}$$ to $$7\times 10^{3}$$ J/m $$^{2}$$ —in the range of effective normal stresses from $$10^{2}$$ to $$10^{5}$$ kPa. An empirical equation is presented for a first-order estimate of the shear fracture energy under a given effective normal stress. The characteristic slip displacements at the laboratory scale are calculated to be smaller than 6 mm, and they appear independent of the effective normal stress. Compared with their nominal values calculated without considering the change of normal stress in triaxial tests, the shear fracture energies are approximately 70% of the nominal values, whereas the characteristic slip displacements are nearly identical to the nominal ones.

Evolution of dynamic shear strength of frictional interfaces during rapid normal stress variations

Pressure shear plate impact tests have revealed that when normal stress changes rapidly enough, the frictional shear resistance is no longer proportional to the normal stress but rather evolves with slip gradually. Motivated by these findings, we focus on characterizing the dynamic shear strength of frictional interfaces subject to rapid variations in normal stress. To study this problem, we use laboratory experiments featuring dynamic shear cracks interacting with a free surface and resulting in pronounced and rapid normal stress variations. As dynamic cracks tend to propagate close to the wave speeds of the material, capturing their behavior poses the metrological challenge of resolving displacements on the order of microns over timescales microseconds. Here we present our novel approach to quantify the full-field behavior of dynamic shear ruptures and the evolution of friction during sudden variations in normal stress, based on ultrahighspeed photography (at 1-2 million frames/sec) combined with digital image correlation. Our measurements allow us to capture the evolution of dynamic shear cracks during these short transients and enable us to decode the nature of dynamic friction.

A Systematic Approach to Mapping Regimes of Earthquake‐Induced Static Stress Changes Acting on Magmatic Pathways

AbstractLarge earthquakes alter the crustal stress field across great distances (hundreds to thousands of kilometers) over geologically short timescales (seconds to years). These stress changes can affect magmatic systems, triggering (or suppressing) volcanic unrest and eruption, along with other deeper processes. We use simple kinematic source models in an isotropic elastic half‐space to assess earthquake‐induced static stress changes (>1 kPa) over the entire thickness of the lithosphere and consider the implications for magma ascent and storage. Modeling subduction zone earthquakes, we calculate static normal stress changes with depth on three mutually perpendicular end‐member magma pathways: vertical arc‐parallel, vertical arc‐perpendicular, and horizontal. From this, we define seven stress change regimes within the adjacent volcanic arc. Three of these regimes may strongly encourage magma ascent in dykes by inducing unclamping (decreased compressive normal stress) of vertical pathways which increases in magnitude toward the surface and clamping of horizontal pathways. Two of the regimes may encourage stalling and storage of magma in sills near the base of the crust by inducing unclamping of horizontal pathways at depth. The spatial distribution of the regimes is largely dependent on earthquake magnitude, but also varies with slip distribution and interface dip. We show how the responses of magmatic systems to earthquakes also depends on the stress change magnitude and the state of the magmatic system, with a greater impact expected for larger stress changes acting on weaker, more thermally mature systems.

INVESTIGATION OF LONGITUDINAL STABILITY PROCESS AT ROLLING WITH STRIP TENSION

Earlier in the works, a qualitative construction of the diagram of changes in longitudinal normal stresses in the case of thin-sheet rolling with strip tension was proposed.. On the basis of the proposed stress distribution, the internal longitudinal forces were determined in a dimensionless form. Knowing these values, it is possible to determine the average resultant longitudinal force of the plastically deformed metal during rolling with the strip tension. It is shown that the value of the mean resulting internal forces is a more stringent boundary condition for the rolling process than the equality of the angle of the neutral section to zero.In this work, the influence of the strip tension mode on the ultimate stability of the metal in the rolls was determined, as well as the limiting condition of rolling, the change in the moment in the deformation zone and the angle of the neutral section. The theoretical analysis was carried out proceeding from the solution of the equilibrium equation with the specific friction forces specified by the Coulomb model. Using the technique proposed in previous works, we studied the effect of the magnitude and mode of strip tension on the longitudinal stability of the sheet during continuous rolling. It is shown that the rear tension has a significant effect on the average resultant longitudinal internal forces, and thereby predetermines the boundary conditions of the rolling process. The boundary conditions of deformation in a steady-state process presented in this work and generally accepted in theory differ significantly, which should be taken into account when developing a technology for continuous sheet rolling.

The Impact of Large Erosional Events and Transient Normal Stress Changes on the Seismicity of Faults

AbstractThe long‐term erosion of steep landscapes is punctuated by dramatic erosional events that can remove significant amount of sediments within a timescale shorter than a seismic cycle. However, the role of such large erosional events on seismicity is poorly understood. We use QDYN, a quasi‐dynamic numerical model of earthquake cycles to investigate the effect of a large erosional event on seismicity. The progressive evacuation of landslide sediments is modeled by a transient normal stress decrease. We show that erosional events with a shorter duration compared with the duration of a seismic cycle can significantly increase the seismicity rate, even for small stress changes. Moreover, large erosional events with a shorter period compared with the earthquake nucleation timescale can change earthquake size distribution by triggering more small events. Those results suggest that large erosional events can significantly affect seismicity, illustrating in turn the short‐term impact of surface processes on tectonics.

Earthquake triggering model based on normal-stress-dependent Nagata law: application to the 2016 Mie offshore earthquake

We propose a normal-stress-dependent Nagata law. Nagata et al. (J Geophys Res 117:B02314, 2012) revised the rate- and state-dependent friction law by introducing the shear stress dependence. We further extended the Nagata law by incorporating the normal stress dependence obtained by Linker and Dieterich (J Geophys Res 97:4923–4940, 1992). We performed numerical simulations of earthquake triggering by assuming the extended Nagata law. In the case of repeated earthquakes, we applied dynamic Coulomb failure function (CFF) perturbation due to normal or shear stress changes. CFF perturbation increased the slip velocity after the cessation of perturbation, relative to that of the repeated events without triggering. This leads to dynamic earthquake triggering for certain perturbation amplitudes with time to instability of 0 to several tens of days. In addition, triggering potential of the static CFF jump (ΔCFFs) was investigated. Static stress perturbation has a higher triggering potential than dynamic stress perturbation for the same magnitude of CFF. The equivalent ΔCFFeq is evaluated for dynamic perturbation that results in a triggering potential approximately the same as in the case of static stress perturbation if ΔCFFs = ΔCFFeq. We calculated ΔCFFeq on the interface of the Philippine Sea plate for the Mie offshore earthquake, which occurred around the Nankai Trough on April 1, 2016, using OpenSWPC. The results shows that ΔCFFeq is large around the trough, where slow slip events followed the Mie earthquake, suggesting that a large ΔCFFeq may have triggered slow slip events.

Hydraulic Injection‐Induced Velocity Changes Revealed by Surface Wave Coda and Polarization Data at a Shale Play Site in Southwest China

AbstractWe investigated temporal variations of seismic wave velocity associated with hydraulic fracturing using Green's functions computed from ambient noise data. In October and November of 2014, we set up a broadband array at a shale play site inside the Sichuan basin where a pilot horizontal drilling and hydraulic injections were conducted. We first computed cross‐correlation functions using continuous data recorded by 21 three‐component broadband sensors deployed around the treatment well. We then employed a running window correlation‐based coda wave interferometry technique to measure apparent velocity changes from the daily Green's functions of all the station pairs in the frequency range of 1 to 3 Hz. We found significant velocity changes right after the hydraulic fracturing, which exhibited a clear direction‐dependent pattern. S wave velocity along raypaths parallel to the well trajectory showed a clear increase while those perpendicular exhibited a small decrease. The anisotropic changes in seismic velocity observed here were also confirmed from surface wave horizontal particle motion data. By comparing our observations with normal stress changes calculated with a half‐space elastic model, we speculate that stress changes induced by the hydraulic fracturing were likely to be responsible for the observed anisotropic changes in seismic velocity. Our results suggest that time‐lapse seismic imaging with ambient noise data provides a promising probe for monitoring geomechanical changes related to exploitation of unconventional oil and gas resources.

Illuminating the physics of dynamic friction through laboratory earthquakes on thrust faults

Large, destructive earthquakes often propagate along thrust faults including megathrusts. The asymmetric interaction of thrust earthquake ruptures with the free surface leads to sudden variations in fault-normal stress, which affect fault friction. Here, we present full-field experimental measurements of displacements, particle velocities, and stresses that characterize the rupture interaction with the free surface, including the large normal stress reductions. We take advantage of these measurements to investigate the dependence of dynamic friction on transient changes in normal stress, demonstrate that the shear frictional resistance exhibits a significant lag in response to such normal stress variations, and identify a predictive frictional formulation that captures this effect. Properly accounting for this delay is important for simulations of fault slip, ground motion, and associated tsunami excitation.

Tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its adjacent areas*

To investigate the tidal effects on intra-continental earthquake initiation in the Tibetan Plateau and its surrounding areas, we selected over 1,500 focal mechanism solutions of inland earthquakes (epicenter locates at least 100 km to the coastlines) from Global Centroid Moment Tensor (GCMT) project and analyzed the p-values of tidal normal and shear stress as well as tidal Coulomb failure stress. For Coulomb failure stress calculation, we used Coulomb 3.40 software. We find that: (1) p-values of tidal stress change suggests a high tidal correlation of earthquake imitations with tidal normal stress change; (2) when tidal normal stress reached the local maximum values of compression and when tidal shear stress were closed to the positive peaks, earthquakes generated more frequently; (3) particular seismogenic environments such as strong continental plate interactions and the existence of fluids or rheologic substance possibly raise the tidal correlations and (4) higher sensitivity of earthquake initiation to earth tide presents along with higher seismicity, suggesting the rate of rain energy accumulation somehow has a dominating effect on the tidal correlation of earthquake initiation.

Shear strength of landfill liner interface in the case of varying normal stress

Landfills are sequentially filled by solid waste lifts, thus normal stress on the liner interface changes in different shear stages, which may affect selection of interface strength in landfill slope stability analysis. Shear tests were conducted at the liner interfaces of geomembrane/geotextile (GM/GT) and geomembrane/geocomposite/sand (GM/GC/Sand), and the normal stress changed in different shear stages. Values of friction angles on both the GM/GT and GM/GC/Sand interfaces obtained by direct and simple shear tests under increasing normal stress in the hardening, softening, and large-displacement stages were lower than those obtained by the traditional direct shear test. The reduction was greater for peak friction angles. Since the peak liner interface strength obtained by staged loading is lower than the peak interface strength by using the traditional shear test method, using the peak shear strength obtained from the traditional direct shear test for the base floor liner to conduct slope stability analysis may cause an un-conservative result. It is necessary to consider the effects of normal stress changes on the liner interface strength in landfill slope stability analysis.

Stress Changes on the Garlock Fault during and after the 2019 Ridgecrest Earthquake Sequence

ABSTRACTThe recent 2019 Ridgecrest earthquake sequence in southern California jostled the seismological community by revealing a complex and cascading foreshock series that culminated in a Mw 7.1 mainshock. But the central Garlock fault, despite being located immediately south of this sequence, did not coseismically fail. Instead, the Garlock fault underwent postseismic creep and exhibited a sizeable earthquake swarm. The dynamic details of the rupture process during the mainshock are largely unknown, as is the amount of stress needed to bring the Garlock fault to failure. We present an integrated view of how stresses changed on the Garlock fault during and after the mainshock using a combination of tools including kinematic slip inversion, Coulomb stress change (ΔCFS), and dynamic rupture modeling. We show that positive ΔCFSs cannot easily explain observed aftershock patterns on the Garlock fault but are consistent with where creep was documented on the central Garlock fault section. Our dynamic model is able to reproduce the main slip asperities and kinematically estimated rupture speeds (≤2 km/s) during the mainshock, and suggests the temporal changes in normal and shear stress on the Garlock fault were the greatest near the end of rupture. The largest static and dynamic stress changes on the Garlock fault we observe from our models coincide with the creeping region, suggesting that positive stress perturbations could have caused this during or after the mainshock rupture. This analysis of near-field stress-change evolution gives insight into how the Ridgecrest sequence influenced the local stress field of the northernmost eastern California shear zone.

INTERACTION OF POST FOUNDATIONS AND FROZEN SOILS

The frozen soils’ stress-strain state varies with time due to the internal soil rheological processes. Those processes become active within the thawing period of the active soil layer causing increase in settlement of the engineering structures’ foundations. Hence, creep processes and thawing of frozen soils should be considered when designing the transportation facilities for regions of the Far North and Siberia.The objective of the research is to develop a procedure for evaluating the variation in time of the stress-strain state of the frozen soil under the post footing of a bridge pier’s foundation considering the frozen soil creep and thawing. The interaction of the bridge pier post foundations and frozen silt-loam soil is modelled and studied. The research is based on the example of an existing overpass over the M‑56 Lena motor road situated at Amga–Samyrdah stage of Tommot–Yakutsk section of the Berkakit–Tommot–Yakutsk railway line. This overpass has piers with post foundations. The above railway line is in the area of hard frozen soils.The study focuses on changes in principal normal compressive stresses with the course of time, as well as on the frozen soil movements under the post footing. The time allotted for the above system behavior study is limited to five months. There are two design cases: a) considering the frozen soil thawing up to a depth range of 1,5 to 4 m; b) without considering the frozen soil thawing.The research has shown that the thawing of the frozen soil up to a comparatively low depth as compared to natural level results in a significant increase (by 2÷2,5 times) in the values of post foundation settlement as compared with the design case without thawing. At the same time, it was found that small values of thawing have a subtle effect on the frozen soil’s stress state under the post footing. Besides, all reviewed design cases (with / without thawing revealed that stress of the frozen soil under the post footing decreases with time (stress relaxation).

Empirical ratio of dynamic to static stiffness for propped artificial fractures under variable normal stress

The stiffness coefficient is a key parameter of rock fractures that controls the properties and behavior of a rock mass. According to the displacement discontinuity theory, the dynamic stiffness of rock fractures can be back analyzed using stress wave propagation. This study aims to measure the dynamic stiffness of rock fractures then develop an empirical ratio to describe the relationship between dynamic and static stiffness. Propped artificially fractured shale and granitic rock samples are employed. Mechanical and ultrasonic tests are conducted on two artificial rock fractures during uniaxial loading and unloading. As normal stress changes from 1 MPa to 50 MPa, the average dynamic normal stiffness of shale and granitic rock fractures changes from 330 GPa/m to 1960 GPa/m and from 90 GPa/m to 2320 GPa/m, respectively. For both artificial fractures, the dynamic stiffness is higher than the static stiffness but approaches the static stiffness with increasing normal stress. The ratio of dynamic to static normal stiffness is approximately 2.0 at a normal stress of 15 MPa; this ratio approaches 1.0 with increasing normal stress and varies widely under low normal stress. This study provides a method for evaluating the static or dynamic stiffness of rock fractures, which has important applications for seismic surveys or acoustic logs in the field of geological engineering.

Poroelastic models for fault reactivation in response to concurrent injection and production in stacked reservoirs

Concurrent production and injection in stacked reservoirs as commonly conducted in unconventional resource exploitation potentially influences reactivation of nearby faults. Using three-dimensional, fully-coupled poroelastic finite-element simulations, we assessed the potential for reactivation of a barrier normal fault in a normal-faulting stress regime for twelve generic injection–production scenarios that differ in the depth of injection and production, and in the position and distance relative to the dipping fault plane. The simulations display significant variation in the Coulomb failure stress (CFS) with depth along the fault plane for these scenarios, reflecting differences in pore pressure distribution and associated poroelastic changes in normal and shear stress across the fault. Based on the CFS trends with depth we find that 1.) concurrent production and injection reduces or increases the fault reactivation potential in the injection reservoir depending on the lateral position and the distance of the wellbores relative to the fault plane; 2.) the fault is most prone to reactivation with stacked wellbores and injection into the upper reservoir within the hanging wall or the lower reservoir within the footwall, and 3.) the fault is least prone to injection-induced reactivation for stacked wellbores and injection into the lower reservoir within the hanging wall at wellbore-to-fault distances ten times the reservoir thickness. With decreasing wellbore-to-fault distance, induced poroelastic shear stresses and thus CFS increase, making injection only into the lower reservoir, without concurrent production, the most stable configuration at close distance. These simulations demonstrate the importance of the coupled poroelastic effects and of the three-dimensional arrangement of injection and production wellbores on fault reactivation. Our results are intended to provide general guidance for further detailed site-specific geomechanical evaluations needed for induced seismic hazard assessment.