The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy(RMEA)and its systematic comparison with pure niobium(Nb).Fully-recrystallized specimens ...The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy(RMEA)and its systematic comparison with pure niobium(Nb).Fully-recrystallized specimens were fabricated by cold rolling and subsequent annealing,and uniaxial tensile deformation was applied at room temperature.Slip trace morphologies on the surfaces of the tensile-deformed ma-terials were quantitatively characterized,and the so-calledψand x relationships of the observed slip traces were evaluated by a newly developed method for polycrystalline specimens.Wavy slip traces were observed in most grains in the pure Nb.They consisted of low-indexed slip planes,such as{110},and{112},and high-indexed(or undetermined)slip planes.Some straight slip traces persisting on the low-indexed slip planes were also found in the pure Nb.In contrast,straight slip traces were dominant in the RMEA.The straight slip traces in the RMEA were not parallel to particular slip planes but mostly distributed along the maximum shear stress plane(MSSP),indicating that frequent cross slip in very short intervals occurred.Large deviations of slip planes from the MSSP in a few grains of the RMEA were attributed to the slip transfer from neighboring grains as a characteristic of polycrystalline materi-als.Frequent cross slip in short intervals,attributed to homogeneous slip resistance distribution for screw dislocations in the RMEA originating from the chemical heterogeneity on an atomic scale,was proposed as a novel mechanism responsible for the unique slip behavior and macroscopic deformation behavior.展开更多
The grain-scale tension-compression(T-C)asymmetric slip behavior and geometrically necessary dislocation(GND)density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and elect...The grain-scale tension-compression(T-C)asymmetric slip behavior and geometrically necessary dislocation(GND)density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and electron backscatter diffraction(EBSD)analysis.A significantly asymmetric slip activity,i.e.,higher tensile slip activity and proportion of non-basal slip,was manifested.Prismatic〈a〉(37.1%)and basal〈a〉(27.6%)slips dominated the tensile deformation,followed by pyramidalⅡ〈c+a〉slip(20.0%).While during compression,basal〈a〉slip(61.9%)was the most active slip mode,and only 6.9% pyramidalⅡ〈c+a〉slip was observed.The critical resolved shear stress(CRSS)ratio was estimated based on~800 sets of the identified slip traces,which suggested that the CRSS_(pyrⅡ)/CRSS_(bas)for compression was~3 times than that of tension.The pyramidalⅡ〈c+a〉slip was more active when the slip plane was under tension than under compression,which was consistent with the calculated asymmetric CRSS_(pyrⅡ)/CRSS_(bas).The activity of multiple slip,cross slip and slip transfer,as well as the GND density were also T-C asymmetric.This work thoughtfully demonstrated the T-C asymmetric slip behavior and plastic heterogeneity in Mg alloys which was believed to be responsible for the macroscopic T-C asymmetry when twinning was absent.The present statistical results are valuable for validating and/or facilitating crystal plasticity simulations.展开更多
This work investigated the effects of grain size(GS)on individual slip mode activities and the corresponding Hall-Petch coefficients in a rolled basal-textured pure Mg sheet under uniaxial tension using statistical sl...This work investigated the effects of grain size(GS)on individual slip mode activities and the corresponding Hall-Petch coefficients in a rolled basal-textured pure Mg sheet under uniaxial tension using statistical slip trace analysis and electron backscatter diffraction.The studied regions covered a total of 1150 grains,in which 136 sets of slip traces were identified and analyzed in detail.The basalslip always dominated the deformation,whose frequencies decreased(from 81.0%to 62.5%)with increasing GS(from 10 to 85μm).The prismaticslip activity increased from 10.8%(10μm)to 27.5%(85μm),while that for pyramidal II<c+a>slip was almost constant.Critical resolved shear stress(CRSS)ratios were estimated based on the identified slip activity statistics,and then the Hall-Petch coefficients(k)of individual slip modes were calculated.The k value for prismaticslip(194 MPa·μm^(1/2))was lower than that for pyramidal II<c+a>slip(309 MPa·μm^(1/2)),which implies that pyramidal II<c+a>slip was more GS sensitive.Twinning activity exhibited a positive correlation with GS,though it remained limited partly due to the unfavorable loading direction.The macroscopic Hall-Petch relationship was divided into two regions,i.e.,the k value(753 MPa·μm^(1/2))for the coarse-grain region(30-85μm)was significantly larger than that(118 MPa·μm^(1/2))of the fine-grain region(10-30μm),which could be attributed to the transition of predominant deformation mechanisms from slip to slip combined twinning with increasing GS.This work provides detailed and quantitative experimental data of the GS effects on individual slip activities of Mg and provides new insights into the Hall-Petch relationship for individual slip modes.展开更多
This study proposes an alternative calculation mode for stresses on the slip surface(SS).The calculation of the normal stress(NS)on the SS involves examining its composition and expanding its unknown using the Taylor ...This study proposes an alternative calculation mode for stresses on the slip surface(SS).The calculation of the normal stress(NS)on the SS involves examining its composition and expanding its unknown using the Taylor series.This expansion enables the reasonable construction of a function describing the NS on the SS.Additionally,by directly incorporating the nonlinear Generalized Hoke-Brown(GHB)strength criterion and utilizing the slope factor of safety(FOS)definition,a function of the shear stress on the SS is derived.This function considers the mutual feedback mechanism between the NS and strength parameters of the SS.The stress constraints conditions are then introduced at both ends of the SS based on the spatial stress relation of one point.Determining the slope FOS and stress solution for the SS involves considering the mechanical equilibrium conditions and the stress constraint conditions satisfied by the sliding body.The proposed approach successfully simulates the tension-shear stress zone near the slope top and provides an intuitive description of the concentration effect of compression-shear stress of the SS near the slope toe.Furthermore,compared to other methods,the present method demonstrates superior processing capabilities for the embedded nonlinear GHB strength criterion.展开更多
A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during ...A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during underground coal mining.This would trigger strong rockburst disasters.To understand the occurrence of fault-slip induced rockbursts,we developed a physical model test system for fault-slip induced rockbursts in coal mine drifts.The boundary energy storage(BES)loading apparatus and bottom rapid retraction(BRR)apparatus are designed to realize energy compensation and continuous boundary stress transfer of the surrounding rocks for instantaneous fault slip,as well as to provide space for the potential fault slip.Taking the typical fault-slip induced rockburst in the Xinjulong Coal Mine,China,as the background,we conducted a model test using the test system.The deformation and stress in the rock surrounding the drift and the support unit force during fault slip are analyzed.The deformation and failure characteristics and dynamic responses of drifts under fault-slip induced rockbursts are obtained.The test results illustrate the rationality and effectiveness of the test system.Finally,corresponding recommendations and prospects are proposed based on our findings.展开更多
Given the limitations of traditional hot extrusion methods in improving the microstructure and mechanical properties of magnesium(Mg)alloys,this paper attempts to treat AZ31 Mg alloy billet by pre-upsetting continuous...Given the limitations of traditional hot extrusion methods in improving the microstructure and mechanical properties of magnesium(Mg)alloys,this paper attempts to treat AZ31 Mg alloy billet by pre-upsetting continuous variable cross-section direct extrusion(U-CVCDE).The effects of dynamic recrystallization behavior and slip system activity on texture evolution and mechanical properties of CVCDE Mg alloys with different pre-upsetting amounts were systematically analyzed.The results indicate that the introduction of the pre-upsetting process promotes dynamic recrystallization during the CVCDE process.The recrystallization proportion shows a trend of first rising and then decreasing with the increase of the pre-upsetting amount.Among them,the proportion of recrystallization grains in the U2-CVCDE-formed structural parts is as high as 88.3%.The average grain sizes of U1-CVCDE,U2-CVCDE,and U3-CVCDE were 6.01μm,4.90μm,and10.45μm,respectively.In addition,following U-CVCDE,the pyramidal slip of each forming component consistently maintains a high level of activation and opening and dominates,making more grains deflect in the axial extrusion direction of C to varying degrees,which is conducive to the uniform distribution of stress in more grains during plastic deformation.The synergistic effect of dynamic recrystallization behavior and the high activity of the pyramidal slip system significantly weakened the(0001)basal texture strength,and the maximum basal texture strength showed a gradually decreasing trend,among which the base surface texture strength of U3-CVCDE formed parts was only 9.9.The U-CVCDE process is employed to achieve deep modification of Mg alloy,and excellent comprehensive mechanical properties are obtained;among them,the yield and tensile strength of U2-CVCDE are as high as 243.4 MPa and 317.5 MPa,respectively,and the elongation after breaking is up to 21.3%.This study introduces a practical new idea for investigating the extrusion forming technology of high-performance Mg alloys.展开更多
The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of ...The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.展开更多
Dynamic recrystallization(DRX)in inhomogeneous deformation zones,such as grain boundaries,shear bands,and deformation bands,is critical for texture modification in magnesium alloys during deformation at elevated temper...Dynamic recrystallization(DRX)in inhomogeneous deformation zones,such as grain boundaries,shear bands,and deformation bands,is critical for texture modification in magnesium alloys during deformation at elevated temperatures.This study investigates the DRX mechanisms in AZWX3100 magnesium alloy under plane strain compression at 200℃.Microstructural analysis revealed necklace-type DRX accompanied by evidence of local grain boundary bulging.Additionally,ribbons of recrystallized grains were observed withinfine deformation bands,aligned with theoretical pyramidal I and II slip traces derived from the matrix.The distribution of local misorientation within the deformed microstructure demonstrated a clear association between deformation bands and localized strain.Dislocation analysis of lamellar specimens extracted from two pyramidal slip bands revealed<c+a>dislocations,indicating a connection between<c+a>slip activation and the formation of deformation bands.Crystal plasticity simulations suggest that the orientation of deformation bands is responsible for the unique recrystallization texture of the DRX grains within these bands.The texture characteristics imply a progressive,glide-induced DRX mechanism.A fundamental understanding of the role of deformation bands in texture modification can facilitate future alloy and process design.展开更多
Steel-concrete composite beams,due to their superior mechanical properties,are widely utilized in engineering structures.This study systematically investigates the calculation methods for internal forces and load-bear...Steel-concrete composite beams,due to their superior mechanical properties,are widely utilized in engineering structures.This study systematically investigates the calculation methods for internal forces and load-bearing capacity of composite beams based on elastic theory,with a focus on the transformed section method and its application under varying neutral axis positions.By deriving the geometric characteristics of the transformed section and incorporating a reduction factor accounting for slip effects,a computational model for sectional stress and ultimate load-bearing capacity is established.The results demonstrate that the slip effect significantly influences the flexural load-bearing capacity of composite beams.The proposed reduction factor,which considers the influence of the steel beam’s top flange thickness,offers higher accuracy compared to traditional methods.These findings provide a theoretical foundation for the design and analysis of composite beams,with significant practical engineering value.展开更多
The thermal effect has a significant impact on the activation and slip characteristics of fractures.In this study,four pairs of granite fractures were treated by temperatures T ranging from 25℃to 900℃.The fractures ...The thermal effect has a significant impact on the activation and slip characteristics of fractures.In this study,four pairs of granite fractures were treated by temperatures T ranging from 25℃to 900℃.The fractures were then employed to carry out triaxial unloading-induced shear slip experiments.The step unloading of confining pressure σ_(3) was used as a disturbed stress to activate fractures that were in a near-critical stress state.The slip characteristics,frictional behaviors,as well as damage modes of fractures with different T,were systematically investigated.The results show that at T=25℃ and 300℃,no stick-slip events were observed,and the slipping process of the fractures was characterized by aseismic slip and creep,respectively.For T=600℃ and 900℃,the fractures slipped stably,with occasional interruptions by episodic stick-slip events.Ultimately,they entered the dynamic slip stage after a series of consecutive stick-slip episodes.With increasing T,the number of sheared-off asperities increases due to thermal damage,which in turn leads to an increase in the occurrence of stick-slip events.The slip modes of the fractures transited from friction strengthening to friction weakening.As T increased from 300℃to 900℃,a considerable quantity of generated gouge layer acted as a lubricant for the slipping of fractures.This resulted in a notable increase in the proportion of aseismic slip,which rose from 24%to 54%.As the temperature increased from 25℃to 900℃,the crack length increased exponentially from 2.975 mm to 45.349 mm.For T=600℃ and 900℃,the duration between stick-slip events decreased as stick-slip events occurred more frequently.展开更多
Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior an...Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior and its influencing factors are important for the long-term performance assessment of DGRs.We designed multistage mechanical(M)shear tests and thermomechanical(TM)shear tests on three 100 mm-cubic granite specimens,each containing a single inclined sawcut fracture with distinct microroughness of 8-15μm.M test results have shown that the static friction coefficient of the granite fracture decreases in proportion to the increase in the logarithm of the loading rate within the range of 1-15 kPa/s.For the given heating and boundary conditions,thermal loading rate,i.e.,thermal stress increment with heating time,is measured to be around 1 kPa/s in the fractured granite.Thermoshearing can be well predicted by the linear Mohr-Coulomb failure envelope deduced from M shear tests employing a loading rate that is comparable with the thermal loading rate.The granite fractures exhibited two distinct slip patterns during the mechanical shearing,i.e.,stick-slip observed in the smooth fracture and stable sliding in the relatively rough surface.In contrast,the mechanical loading rate(1-15 kPa/s)investigated in this study appears to not influence the slip pattern.Unlike those in M shear tests,thermoshearing in both smooth and relatively rough fractures show stable sliding with a very slow peak velocity of around 0.002μm/s.展开更多
Earthquakes are caused by the rapid slip along seismogenic faults.Whether large or small,there is inevitably a certain nucleation process involved before the dynamic rupture.At the same time,significant foreshock acti...Earthquakes are caused by the rapid slip along seismogenic faults.Whether large or small,there is inevitably a certain nucleation process involved before the dynamic rupture.At the same time,significant foreshock activity has been observed before some but not all large earthquakes.Understanding the nucleation process and foreshocks of earthquakes,especially large damaging ones,is crucial for accurate earthquake prediction and seismic hazard mitigation.The physical mechanism of earthquake nucleation and foreshock generation is still in debate.While the earthquake nucleation process is present in laboratory experiments and numerical simulations,it is difficult to observe such a process directly in the field.In addition,it is currently impossible to effectively distinguish foreshocks from ordinary earthquake sequences.In this article,we first summarize foreshock observations in the last decades and attempt to classify them into different types based on their temporal behaviors.Next,we present different mechanisms for earthquake nucleation and foreshocks that have been proposed so far.These physical models can be largely grouped into the following three categories:elastic stress triggering,aseismic slip,and fluid flows.We also review several recent studies of foreshock sequences before moderate to large earthquakes around the world,focusing on how different results/conclusions can be made by different datasets/methods.Finally,we offer some suggestions on how to move forward on the research topic of earthquake nucleation and foreshock mechanisms and their governing factors.展开更多
Magnesium(Mg)alloys are usually subjected to torsion deformation during processing or manufacturing.However,the torsional behavior remains underexplored at the atomic level compared to uniaxial deformation.In this wor...Magnesium(Mg)alloys are usually subjected to torsion deformation during processing or manufacturing.However,the torsional behavior remains underexplored at the atomic level compared to uniaxial deformation.In this work,atomistic simulations are employed to understand the deformation mechanism during torsion around <1010>and<1120>axes of Mg.We reveal that the onset of plasticity occurs near the surface due to stress-gradient effect and the deformation mechanisms are highly dependent on torsion axis.Specifically,the prismatic and basal slip dominate torsion around[1120]axis.During torsion around[1010]axis,{1121}twinning can be activated,whereas{1011}twinning is formed due to local stress but detwinned eventually.Moreover,extensive cross slip and interactions between basal and prismatic dislocations are observed and the associated mechanisms are discussed.These novel atomic-scale insights provide deeper understanding of the plastic deformation mechanisms of Mg under torsional loading.展开更多
In this study,we employed Bayesian inversion coupled with the summation-by-parts and simultaneousapproximation-term(SBP-SAT)forward simulation method to elucidate the mechanisms behind mininginduced seismic events cau...In this study,we employed Bayesian inversion coupled with the summation-by-parts and simultaneousapproximation-term(SBP-SAT)forward simulation method to elucidate the mechanisms behind mininginduced seismic events caused by fault slip and their potential effects on rockbursts.Through Bayesian inversion,it is determined that the sources near fault FQ14 have a significant shear component.Additionally,we analyzed the stress and displacement fields of high-energy events,along with the hypocenter distribution of aftershocks,which aided in identifying the slip direction of the critically stressed fault FQ14.We also performed forward modeling to capture the complex dynamics of fault slip under varying friction laws and shear fracture modes.The selection of specific friction laws for fault slip models was based on their ability to accurately replicate observed slip behavior under various external loading conditions,thereby enhancing the applicability of our findings.Our results suggest that the slip behavior of fault FQ14 can be effectively understood by comparing different scenarios.展开更多
Refractory high-entropy alloys(RHEAs)exhibit outstanding strength at room temperature,but their high-temperature applications are hindered by severe strain-softening.Here,we report slip-band-driven dy-namic recrystall...Refractory high-entropy alloys(RHEAs)exhibit outstanding strength at room temperature,but their high-temperature applications are hindered by severe strain-softening.Here,we report slip-band-driven dy-namic recrystallization to enhance the high-temperature strain hardening of HfNbTaTiZr RHEA.By intro-ducing partial lattice defects through hot forging,we increase the nucleation sites for dynamic recrys-tallization during subsequent thermomechanical deformation,thus suppressing the strain-softening be-havior.We reveal that the high-temperature deformation is governed by the formation of heterogeneous bimodal grains along slip bands,which effectively constrain dislocation motion and improve strength,while microbands prevent premature failure.The fracture mode also changes from ductile to mixed to cleavage-dominated with increasing temperature.Our results demonstrate a simple and effective method for overcoming high-temperature strain-softening for BCC high entropy alloys.展开更多
Shear strain energy is a pivotal physical quantity in the occurrence of earthquakes and rockbursts during deep mining operations.This research is focused on understanding the changes in shear strain energy in the cont...Shear strain energy is a pivotal physical quantity in the occurrence of earthquakes and rockbursts during deep mining operations.This research is focused on understanding the changes in shear strain energy in the context of retreating longwall mining,which is essential for the optimized design and mitigation of rockbursts and seismic events.Through the application of innovative analytical models,this study expands its analytical range to include the variations in shear strain energy caused by fault coseismic slip.An integrated methodology is utilized,taking into account the changes in coseismic and fault friction parameters as well as enhancements in mining-induced stress and existing background stresses.Our numerical investigation highlights the significance of mining location and fault characteristics as key determinants of shear strain energy modifications.The analysis demonstrates significant spatial variability in shear strain energy,especially noting that fault slip near the mining face greatly increases the likelihood of rockburst.This finding emphasizes the need to integrate fault coseismic slip dynamics into the triggering factors of rock(coal)bursts,thus broadening the theoretical foundation for addressing geological hazards in deep mining operations.The results are further corroborated by observational data from the vicinity of the F16 fault zone,introducing the concept of mining-induced fault coseismic slip as an essential element in the theoretical framework for understanding rockburst triggers.展开更多
Various slow slip events(SSEs)with distinct characteristics have been detected globally,particularly in regions with dense Global Navigation Satellite Systems(GNSS)networks.In the Hikurangi subduction zone of New Zeal...Various slow slip events(SSEs)with distinct characteristics have been detected globally,particularly in regions with dense Global Navigation Satellite Systems(GNSS)networks.In the Hikurangi subduction zone of New Zealand,SSEs frequently occur alongside seismic activity,especially in the Manawatu and Kapiti regions.This study analyzes the 2021-2023 Kapiti-Manawatu long-term SSE using daily displacement data(2019-2023)from 53 GPS stations.The network inversion filter(NIF)method is applied to extract slow slip signals,revealing spatial migration with alternating slip between Kapiti and Manawatu,characterized by distinct phases of acceleration and deceleration.Manawatu exhibits higher slip rates,exceeding 4 cm/month,with greater cumulative slip and surface displacement than Kapiti.A moderate temporal correlation(coefficient 0.59)between seismic activity in the region and slip acceleration in Manawatu suggests that seismic events may contribute to the slip,while no significant correlation is observed in Kapiti.展开更多
As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their ...As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms.Physical simulation test represents an efficacious methodology.However,there is currently a lack of simulation devices that can effectively simulate two types of dynamic impact phenomena,including high stress and fault slip dynamic impact.To solve aforementioned issues,the physical simulation test system for dynamic impact in deep roadways developed by authors is employed to carry out comparative tests of high stress and fault slip dynamic impact.The phenomena of high stress and fault slip dynamic impact are reproduced successfully.A comparative analysis is conducted on dynamic phenomena,stress evolution,roadway deformation,and support force.The high stress dynamic impact roadway instability mode,which is characterized by the release of high energy accompanied by symmetric damage,and the fault slip dynamic impact roadway instability mode,which is characterized by the propagation of unilateral stress waves accompanied by asymmetric damage,are clarified.On the basis,the differentiated control concepts for different types of dynamic impact in deep roadways are proposed.展开更多
As a major fault in the northeastern Qinghai-Xizang Plateau,the Haiyuan fault zone is important for understanding the regional deformation.Aiming at the differences in the slip rate and locking degree obtained from di...As a major fault in the northeastern Qinghai-Xizang Plateau,the Haiyuan fault zone is important for understanding the regional deformation.Aiming at the differences in the slip rate and locking degree obtained from different studies,this study constructs a refined block model(including Qilian,Alxa,Ordos,Xining,Haiyuan,and Lanzhou blocks)and uses the grid search and simulated annealing methods to invert GPS data for slip rate and locking degree of the Haiyuan fault zone.The results are as follows:(1)The sinistral slip rates in the western,middle,and eastern segments are 4.93-5.22 mm/a,1.52-4.94 mm/a,and 0.43-1.18 mm/a,decreasing eastward on the whole,while the compression rates are 0.45-1.26 mm/a,0.58-2.62 mm/a,and3.52-4.48 mm/a,increasing eastward on the whole.(2)The locking depth of the western segment increases from about 5 km to about 20 km eastward;the middle segment decreases and then increases eastward;the eastern segment concentrates at about 20 km(PHI is about 0.86).(3)The slip deficit is relatively higher in the Lenglongling,Jinqianghe,Maomaoshan,and Liupanshan faults(averaging about 3.42 mm/a,4.16 mm/a,4.23 mm/a,and 3.43 mm/a within 20 km).(4)The Qilian,Alxa,Xining,Lanzhou,and Haiyuan blocks rotate clockwise,while the Ordos block rotates counterclockwise.Additionally,by comparing different block models,the Haiyuan block should be considered independently.The Haiyuan fault zone adjusts surrounding block movements and uplifts Liupanshan mountain tectonically.The results can provide important references for understanding the regional earthquake risk and deformation mechanism.展开更多
0 INTRODUCTION Turkey is located at the intersection of the Eurasian,Anatolian,Arabian,and African tectonic plates.Due to the ongoing northward compression from the Arabian Plate,the Anatolian Plate is pushed westward...0 INTRODUCTION Turkey is located at the intersection of the Eurasian,Anatolian,Arabian,and African tectonic plates.Due to the ongoing northward compression from the Arabian Plate,the Anatolian Plate is pushed westward in a tectonic escape mechanism,leading to the formation of the North Anatolian fault zone(NAFZ)and the East Anatolian fault zone(EAFZ)(e.g.,Bayrak et al.,2015;Duman and Emre,2013;Reilinger et al.,2006).展开更多
基金supported by the Elements Strategy Initiative for Structural Materials(ESISM,No.JPMXP0112101000)the JSP EIG CONCERT-Japan(No.JPMJSC21C6)+5 种基金the Grant-in-Aid for Scientific Research on Innovative Area“High Entropy Alloys”(Nos.JP18H05455 and JP18H05451)the Grant-in-Aid for Scientific Re-search(A)(Nos.JP20H00306 and JP23H00234)the Grant-in-Aid for Research Activity Start-up(No.JP21K20487)the Grant-in-Aid for Early-Career Scientists(No.JP22K14501)the Grant-in-Aid for JSPS Research Fellow(No.JP18J20766)supported by China Scholarship Council(CSC),China.
文摘The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy(RMEA)and its systematic comparison with pure niobium(Nb).Fully-recrystallized specimens were fabricated by cold rolling and subsequent annealing,and uniaxial tensile deformation was applied at room temperature.Slip trace morphologies on the surfaces of the tensile-deformed ma-terials were quantitatively characterized,and the so-calledψand x relationships of the observed slip traces were evaluated by a newly developed method for polycrystalline specimens.Wavy slip traces were observed in most grains in the pure Nb.They consisted of low-indexed slip planes,such as{110},and{112},and high-indexed(or undetermined)slip planes.Some straight slip traces persisting on the low-indexed slip planes were also found in the pure Nb.In contrast,straight slip traces were dominant in the RMEA.The straight slip traces in the RMEA were not parallel to particular slip planes but mostly distributed along the maximum shear stress plane(MSSP),indicating that frequent cross slip in very short intervals occurred.Large deviations of slip planes from the MSSP in a few grains of the RMEA were attributed to the slip transfer from neighboring grains as a characteristic of polycrystalline materi-als.Frequent cross slip in short intervals,attributed to homogeneous slip resistance distribution for screw dislocations in the RMEA originating from the chemical heterogeneity on an atomic scale,was proposed as a novel mechanism responsible for the unique slip behavior and macroscopic deformation behavior.
基金supported by the National Natural Science Foundation of China(No.52171125)the Sichuan Science and Technology Program(No.2024NSFSC0193)。
文摘The grain-scale tension-compression(T-C)asymmetric slip behavior and geometrically necessary dislocation(GND)density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and electron backscatter diffraction(EBSD)analysis.A significantly asymmetric slip activity,i.e.,higher tensile slip activity and proportion of non-basal slip,was manifested.Prismatic〈a〉(37.1%)and basal〈a〉(27.6%)slips dominated the tensile deformation,followed by pyramidalⅡ〈c+a〉slip(20.0%).While during compression,basal〈a〉slip(61.9%)was the most active slip mode,and only 6.9% pyramidalⅡ〈c+a〉slip was observed.The critical resolved shear stress(CRSS)ratio was estimated based on~800 sets of the identified slip traces,which suggested that the CRSS_(pyrⅡ)/CRSS_(bas)for compression was~3 times than that of tension.The pyramidalⅡ〈c+a〉slip was more active when the slip plane was under tension than under compression,which was consistent with the calculated asymmetric CRSS_(pyrⅡ)/CRSS_(bas).The activity of multiple slip,cross slip and slip transfer,as well as the GND density were also T-C asymmetric.This work thoughtfully demonstrated the T-C asymmetric slip behavior and plastic heterogeneity in Mg alloys which was believed to be responsible for the macroscopic T-C asymmetry when twinning was absent.The present statistical results are valuable for validating and/or facilitating crystal plasticity simulations.
基金supported by the National Natural Science Foundation of China(No.52171125)the Sichuan Science and Technology Program(No.2024NSFSC0193).
文摘This work investigated the effects of grain size(GS)on individual slip mode activities and the corresponding Hall-Petch coefficients in a rolled basal-textured pure Mg sheet under uniaxial tension using statistical slip trace analysis and electron backscatter diffraction.The studied regions covered a total of 1150 grains,in which 136 sets of slip traces were identified and analyzed in detail.The basalslip always dominated the deformation,whose frequencies decreased(from 81.0%to 62.5%)with increasing GS(from 10 to 85μm).The prismaticslip activity increased from 10.8%(10μm)to 27.5%(85μm),while that for pyramidal II<c+a>slip was almost constant.Critical resolved shear stress(CRSS)ratios were estimated based on the identified slip activity statistics,and then the Hall-Petch coefficients(k)of individual slip modes were calculated.The k value for prismaticslip(194 MPa·μm^(1/2))was lower than that for pyramidal II<c+a>slip(309 MPa·μm^(1/2)),which implies that pyramidal II<c+a>slip was more GS sensitive.Twinning activity exhibited a positive correlation with GS,though it remained limited partly due to the unfavorable loading direction.The macroscopic Hall-Petch relationship was divided into two regions,i.e.,the k value(753 MPa·μm^(1/2))for the coarse-grain region(30-85μm)was significantly larger than that(118 MPa·μm^(1/2))of the fine-grain region(10-30μm),which could be attributed to the transition of predominant deformation mechanisms from slip to slip combined twinning with increasing GS.This work provides detailed and quantitative experimental data of the GS effects on individual slip activities of Mg and provides new insights into the Hall-Petch relationship for individual slip modes.
基金Project(52278380)supported by the National Natural Science Foundation of ChinaProject(2023JJ30670)supported by the National Science Foundation of and Technology Major Project of Hunan Province,China。
文摘This study proposes an alternative calculation mode for stresses on the slip surface(SS).The calculation of the normal stress(NS)on the SS involves examining its composition and expanding its unknown using the Taylor series.This expansion enables the reasonable construction of a function describing the NS on the SS.Additionally,by directly incorporating the nonlinear Generalized Hoke-Brown(GHB)strength criterion and utilizing the slope factor of safety(FOS)definition,a function of the shear stress on the SS is derived.This function considers the mutual feedback mechanism between the NS and strength parameters of the SS.The stress constraints conditions are then introduced at both ends of the SS based on the spatial stress relation of one point.Determining the slope FOS and stress solution for the SS involves considering the mechanical equilibrium conditions and the stress constraint conditions satisfied by the sliding body.The proposed approach successfully simulates the tension-shear stress zone near the slope top and provides an intuitive description of the concentration effect of compression-shear stress of the SS near the slope toe.Furthermore,compared to other methods,the present method demonstrates superior processing capabilities for the embedded nonlinear GHB strength criterion.
基金support from the National Natural Science Foundation of China (Grant Nos.51927807,42077267 and 42277174).
文摘A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during underground coal mining.This would trigger strong rockburst disasters.To understand the occurrence of fault-slip induced rockbursts,we developed a physical model test system for fault-slip induced rockbursts in coal mine drifts.The boundary energy storage(BES)loading apparatus and bottom rapid retraction(BRR)apparatus are designed to realize energy compensation and continuous boundary stress transfer of the surrounding rocks for instantaneous fault slip,as well as to provide space for the potential fault slip.Taking the typical fault-slip induced rockburst in the Xinjulong Coal Mine,China,as the background,we conducted a model test using the test system.The deformation and stress in the rock surrounding the drift and the support unit force during fault slip are analyzed.The deformation and failure characteristics and dynamic responses of drifts under fault-slip induced rockbursts are obtained.The test results illustrate the rationality and effectiveness of the test system.Finally,corresponding recommendations and prospects are proposed based on our findings.
基金financially supported by the National Natural Science Foundation of China(No.52475341)the Natural Science Foundation of Heilongjiang Province(No.JQ2022E004)。
文摘Given the limitations of traditional hot extrusion methods in improving the microstructure and mechanical properties of magnesium(Mg)alloys,this paper attempts to treat AZ31 Mg alloy billet by pre-upsetting continuous variable cross-section direct extrusion(U-CVCDE).The effects of dynamic recrystallization behavior and slip system activity on texture evolution and mechanical properties of CVCDE Mg alloys with different pre-upsetting amounts were systematically analyzed.The results indicate that the introduction of the pre-upsetting process promotes dynamic recrystallization during the CVCDE process.The recrystallization proportion shows a trend of first rising and then decreasing with the increase of the pre-upsetting amount.Among them,the proportion of recrystallization grains in the U2-CVCDE-formed structural parts is as high as 88.3%.The average grain sizes of U1-CVCDE,U2-CVCDE,and U3-CVCDE were 6.01μm,4.90μm,and10.45μm,respectively.In addition,following U-CVCDE,the pyramidal slip of each forming component consistently maintains a high level of activation and opening and dominates,making more grains deflect in the axial extrusion direction of C to varying degrees,which is conducive to the uniform distribution of stress in more grains during plastic deformation.The synergistic effect of dynamic recrystallization behavior and the high activity of the pyramidal slip system significantly weakened the(0001)basal texture strength,and the maximum basal texture strength showed a gradually decreasing trend,among which the base surface texture strength of U3-CVCDE formed parts was only 9.9.The U-CVCDE process is employed to achieve deep modification of Mg alloy,and excellent comprehensive mechanical properties are obtained;among them,the yield and tensile strength of U2-CVCDE are as high as 243.4 MPa and 317.5 MPa,respectively,and the elongation after breaking is up to 21.3%.This study introduces a practical new idea for investigating the extrusion forming technology of high-performance Mg alloys.
文摘The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.
基金by the Deutsche Forschungsgemeinschaft(DFG)through projects 420149269,394480829as part of the CRC1394“Structural and Chemical Atomic Complexity-From Defect Phase Diagrams to Material Properties”(project 409476157).
文摘Dynamic recrystallization(DRX)in inhomogeneous deformation zones,such as grain boundaries,shear bands,and deformation bands,is critical for texture modification in magnesium alloys during deformation at elevated temperatures.This study investigates the DRX mechanisms in AZWX3100 magnesium alloy under plane strain compression at 200℃.Microstructural analysis revealed necklace-type DRX accompanied by evidence of local grain boundary bulging.Additionally,ribbons of recrystallized grains were observed withinfine deformation bands,aligned with theoretical pyramidal I and II slip traces derived from the matrix.The distribution of local misorientation within the deformed microstructure demonstrated a clear association between deformation bands and localized strain.Dislocation analysis of lamellar specimens extracted from two pyramidal slip bands revealed<c+a>dislocations,indicating a connection between<c+a>slip activation and the formation of deformation bands.Crystal plasticity simulations suggest that the orientation of deformation bands is responsible for the unique recrystallization texture of the DRX grains within these bands.The texture characteristics imply a progressive,glide-induced DRX mechanism.A fundamental understanding of the role of deformation bands in texture modification can facilitate future alloy and process design.
文摘Steel-concrete composite beams,due to their superior mechanical properties,are widely utilized in engineering structures.This study systematically investigates the calculation methods for internal forces and load-bearing capacity of composite beams based on elastic theory,with a focus on the transformed section method and its application under varying neutral axis positions.By deriving the geometric characteristics of the transformed section and incorporating a reduction factor accounting for slip effects,a computational model for sectional stress and ultimate load-bearing capacity is established.The results demonstrate that the slip effect significantly influences the flexural load-bearing capacity of composite beams.The proposed reduction factor,which considers the influence of the steel beam’s top flange thickness,offers higher accuracy compared to traditional methods.These findings provide a theoretical foundation for the design and analysis of composite beams,with significant practical engineering value.
基金funded by the National Key Research and Development Program of China,(Grant No.2022YFE0128300)the Natural Science Foundation of China(Grant No.52379113)+1 种基金the Fundamental Research Funds for the Central Universities of China(Grant No.2024-10945)the Postgraduate Research&Practice Innovation Program of Jiangsu Province of China.
文摘The thermal effect has a significant impact on the activation and slip characteristics of fractures.In this study,four pairs of granite fractures were treated by temperatures T ranging from 25℃to 900℃.The fractures were then employed to carry out triaxial unloading-induced shear slip experiments.The step unloading of confining pressure σ_(3) was used as a disturbed stress to activate fractures that were in a near-critical stress state.The slip characteristics,frictional behaviors,as well as damage modes of fractures with different T,were systematically investigated.The results show that at T=25℃ and 300℃,no stick-slip events were observed,and the slipping process of the fractures was characterized by aseismic slip and creep,respectively.For T=600℃ and 900℃,the fractures slipped stably,with occasional interruptions by episodic stick-slip events.Ultimately,they entered the dynamic slip stage after a series of consecutive stick-slip episodes.With increasing T,the number of sheared-off asperities increases due to thermal damage,which in turn leads to an increase in the occurrence of stick-slip events.The slip modes of the fractures transited from friction strengthening to friction weakening.As T increased from 300℃to 900℃,a considerable quantity of generated gouge layer acted as a lubricant for the slipping of fractures.This resulted in a notable increase in the proportion of aseismic slip,which rose from 24%to 54%.As the temperature increased from 25℃to 900℃,the crack length increased exponentially from 2.975 mm to 45.349 mm.For T=600℃ and 900℃,the duration between stick-slip events decreased as stick-slip events occurred more frequently.
基金supported by the International Collaborative Research Program(fundamental research,2021-2023)funded by Korea Institute of Civil Engineering and Building Technology(KICT).
文摘Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior and its influencing factors are important for the long-term performance assessment of DGRs.We designed multistage mechanical(M)shear tests and thermomechanical(TM)shear tests on three 100 mm-cubic granite specimens,each containing a single inclined sawcut fracture with distinct microroughness of 8-15μm.M test results have shown that the static friction coefficient of the granite fracture decreases in proportion to the increase in the logarithm of the loading rate within the range of 1-15 kPa/s.For the given heating and boundary conditions,thermal loading rate,i.e.,thermal stress increment with heating time,is measured to be around 1 kPa/s in the fractured granite.Thermoshearing can be well predicted by the linear Mohr-Coulomb failure envelope deduced from M shear tests employing a loading rate that is comparable with the thermal loading rate.The granite fractures exhibited two distinct slip patterns during the mechanical shearing,i.e.,stick-slip observed in the smooth fracture and stable sliding in the relatively rough surface.In contrast,the mechanical loading rate(1-15 kPa/s)investigated in this study appears to not influence the slip pattern.Unlike those in M shear tests,thermoshearing in both smooth and relatively rough fractures show stable sliding with a very slow peak velocity of around 0.002μm/s.
基金supported by U.S.National Science Foundation grant RISE-2425889.
文摘Earthquakes are caused by the rapid slip along seismogenic faults.Whether large or small,there is inevitably a certain nucleation process involved before the dynamic rupture.At the same time,significant foreshock activity has been observed before some but not all large earthquakes.Understanding the nucleation process and foreshocks of earthquakes,especially large damaging ones,is crucial for accurate earthquake prediction and seismic hazard mitigation.The physical mechanism of earthquake nucleation and foreshock generation is still in debate.While the earthquake nucleation process is present in laboratory experiments and numerical simulations,it is difficult to observe such a process directly in the field.In addition,it is currently impossible to effectively distinguish foreshocks from ordinary earthquake sequences.In this article,we first summarize foreshock observations in the last decades and attempt to classify them into different types based on their temporal behaviors.Next,we present different mechanisms for earthquake nucleation and foreshocks that have been proposed so far.These physical models can be largely grouped into the following three categories:elastic stress triggering,aseismic slip,and fluid flows.We also review several recent studies of foreshock sequences before moderate to large earthquakes around the world,focusing on how different results/conclusions can be made by different datasets/methods.Finally,we offer some suggestions on how to move forward on the research topic of earthquake nucleation and foreshock mechanisms and their governing factors.
基金supported by the National Natural Science Foundation of China—Excellent Young Scientists Fund(Overseas)Partial support came from the Fundamental Research Funds for the Central Universities,Jilin University.
文摘Magnesium(Mg)alloys are usually subjected to torsion deformation during processing or manufacturing.However,the torsional behavior remains underexplored at the atomic level compared to uniaxial deformation.In this work,atomistic simulations are employed to understand the deformation mechanism during torsion around <1010>and<1120>axes of Mg.We reveal that the onset of plasticity occurs near the surface due to stress-gradient effect and the deformation mechanisms are highly dependent on torsion axis.Specifically,the prismatic and basal slip dominate torsion around[1120]axis.During torsion around[1010]axis,{1121}twinning can be activated,whereas{1011}twinning is formed due to local stress but detwinned eventually.Moreover,extensive cross slip and interactions between basal and prismatic dislocations are observed and the associated mechanisms are discussed.These novel atomic-scale insights provide deeper understanding of the plastic deformation mechanisms of Mg under torsional loading.
基金the Graduate Innovation Program of China University of Mining and Technology,the Fundamental Research Funds for the Central Universities(Grant No.2023WLKXJ017)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX23_2776)the Shandong Energy Group(Grant No.SNKJ2022BJ03-R28)。
文摘In this study,we employed Bayesian inversion coupled with the summation-by-parts and simultaneousapproximation-term(SBP-SAT)forward simulation method to elucidate the mechanisms behind mininginduced seismic events caused by fault slip and their potential effects on rockbursts.Through Bayesian inversion,it is determined that the sources near fault FQ14 have a significant shear component.Additionally,we analyzed the stress and displacement fields of high-energy events,along with the hypocenter distribution of aftershocks,which aided in identifying the slip direction of the critically stressed fault FQ14.We also performed forward modeling to capture the complex dynamics of fault slip under varying friction laws and shear fracture modes.The selection of specific friction laws for fault slip models was based on their ability to accurately replicate observed slip behavior under various external loading conditions,thereby enhancing the applicability of our findings.Our results suggest that the slip behavior of fault FQ14 can be effectively understood by comparing different scenarios.
基金supported by the Aviation Foundation(No.2023Z0530S6004)Program 173(No.2020-JCIQ-ZD-186-01)+4 种基金the Space Utilization System of China Manned Space Engineering(No.KJZ-YY-NCL08)the Shanghai“Super Postdoc”Incentive Program(No.2023314)the National High-end Foreign Experts Introduction Program(No.G2023014006)the Zhenjiang International Science and Technology Cooperation Program(No.GJ2023011)the Jiangsu University(High-tech ship)Collaborative Innovation Center Program(No.XTCX202401).
文摘Refractory high-entropy alloys(RHEAs)exhibit outstanding strength at room temperature,but their high-temperature applications are hindered by severe strain-softening.Here,we report slip-band-driven dy-namic recrystallization to enhance the high-temperature strain hardening of HfNbTaTiZr RHEA.By intro-ducing partial lattice defects through hot forging,we increase the nucleation sites for dynamic recrys-tallization during subsequent thermomechanical deformation,thus suppressing the strain-softening be-havior.We reveal that the high-temperature deformation is governed by the formation of heterogeneous bimodal grains along slip bands,which effectively constrain dislocation motion and improve strength,while microbands prevent premature failure.The fracture mode also changes from ductile to mixed to cleavage-dominated with increasing temperature.Our results demonstrate a simple and effective method for overcoming high-temperature strain-softening for BCC high entropy alloys.
文摘Shear strain energy is a pivotal physical quantity in the occurrence of earthquakes and rockbursts during deep mining operations.This research is focused on understanding the changes in shear strain energy in the context of retreating longwall mining,which is essential for the optimized design and mitigation of rockbursts and seismic events.Through the application of innovative analytical models,this study expands its analytical range to include the variations in shear strain energy caused by fault coseismic slip.An integrated methodology is utilized,taking into account the changes in coseismic and fault friction parameters as well as enhancements in mining-induced stress and existing background stresses.Our numerical investigation highlights the significance of mining location and fault characteristics as key determinants of shear strain energy modifications.The analysis demonstrates significant spatial variability in shear strain energy,especially noting that fault slip near the mining face greatly increases the likelihood of rockburst.This finding emphasizes the need to integrate fault coseismic slip dynamics into the triggering factors of rock(coal)bursts,thus broadening the theoretical foundation for addressing geological hazards in deep mining operations.The results are further corroborated by observational data from the vicinity of the F16 fault zone,introducing the concept of mining-induced fault coseismic slip as an essential element in the theoretical framework for understanding rockburst triggers.
基金funded by the National Natural Science Foundation of China(41704031,42374040)the Natural Science Foundation of Jiangxi Science and Technology Department(20232BAB203073)the Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake,Ministry of Natural Resources(MEMI-2021-2022-29).
文摘Various slow slip events(SSEs)with distinct characteristics have been detected globally,particularly in regions with dense Global Navigation Satellite Systems(GNSS)networks.In the Hikurangi subduction zone of New Zealand,SSEs frequently occur alongside seismic activity,especially in the Manawatu and Kapiti regions.This study analyzes the 2021-2023 Kapiti-Manawatu long-term SSE using daily displacement data(2019-2023)from 53 GPS stations.The network inversion filter(NIF)method is applied to extract slow slip signals,revealing spatial migration with alternating slip between Kapiti and Manawatu,characterized by distinct phases of acceleration and deceleration.Manawatu exhibits higher slip rates,exceeding 4 cm/month,with greater cumulative slip and surface displacement than Kapiti.A moderate temporal correlation(coefficient 0.59)between seismic activity in the region and slip acceleration in Manawatu suggests that seismic events may contribute to the slip,while no significant correlation is observed in Kapiti.
基金supported by the National Natural Science Foundation of China(Nos.U24A2088,42177130,42277174,and 42477166).
文摘As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms.Physical simulation test represents an efficacious methodology.However,there is currently a lack of simulation devices that can effectively simulate two types of dynamic impact phenomena,including high stress and fault slip dynamic impact.To solve aforementioned issues,the physical simulation test system for dynamic impact in deep roadways developed by authors is employed to carry out comparative tests of high stress and fault slip dynamic impact.The phenomena of high stress and fault slip dynamic impact are reproduced successfully.A comparative analysis is conducted on dynamic phenomena,stress evolution,roadway deformation,and support force.The high stress dynamic impact roadway instability mode,which is characterized by the release of high energy accompanied by symmetric damage,and the fault slip dynamic impact roadway instability mode,which is characterized by the propagation of unilateral stress waves accompanied by asymmetric damage,are clarified.On the basis,the differentiated control concepts for different types of dynamic impact in deep roadways are proposed.
基金supported by the National Natural Science Foundation of China(42474003,42074007)the Fundamental Research Funds for the Central Universities(2042023kfyq01)。
文摘As a major fault in the northeastern Qinghai-Xizang Plateau,the Haiyuan fault zone is important for understanding the regional deformation.Aiming at the differences in the slip rate and locking degree obtained from different studies,this study constructs a refined block model(including Qilian,Alxa,Ordos,Xining,Haiyuan,and Lanzhou blocks)and uses the grid search and simulated annealing methods to invert GPS data for slip rate and locking degree of the Haiyuan fault zone.The results are as follows:(1)The sinistral slip rates in the western,middle,and eastern segments are 4.93-5.22 mm/a,1.52-4.94 mm/a,and 0.43-1.18 mm/a,decreasing eastward on the whole,while the compression rates are 0.45-1.26 mm/a,0.58-2.62 mm/a,and3.52-4.48 mm/a,increasing eastward on the whole.(2)The locking depth of the western segment increases from about 5 km to about 20 km eastward;the middle segment decreases and then increases eastward;the eastern segment concentrates at about 20 km(PHI is about 0.86).(3)The slip deficit is relatively higher in the Lenglongling,Jinqianghe,Maomaoshan,and Liupanshan faults(averaging about 3.42 mm/a,4.16 mm/a,4.23 mm/a,and 3.43 mm/a within 20 km).(4)The Qilian,Alxa,Xining,Lanzhou,and Haiyuan blocks rotate clockwise,while the Ordos block rotates counterclockwise.Additionally,by comparing different block models,the Haiyuan block should be considered independently.The Haiyuan fault zone adjusts surrounding block movements and uplifts Liupanshan mountain tectonically.The results can provide important references for understanding the regional earthquake risk and deformation mechanism.
基金supported by the National Natural Science Foundation of China(Nos.42174023,42304037)the National Key Research and Development Program(No.2022YFB3903602)+1 种基金the Natural Science Foundation of Hunan Province(No.2024JJ3031)the Frontier Cross Research Project of Central South University(No.2023QYJC006)。
文摘0 INTRODUCTION Turkey is located at the intersection of the Eurasian,Anatolian,Arabian,and African tectonic plates.Due to the ongoing northward compression from the Arabian Plate,the Anatolian Plate is pushed westward in a tectonic escape mechanism,leading to the formation of the North Anatolian fault zone(NAFZ)and the East Anatolian fault zone(EAFZ)(e.g.,Bayrak et al.,2015;Duman and Emre,2013;Reilinger et al.,2006).
