Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These roc...Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These rock masses are predominantly composed of sedimentary,para-metamorphic,and volcanic rock types,characterized by a set of prominent,primary bedding structural planes(layers)exhibiting relatively consistent orientations and significant spatial continuity.展开更多
Dangerous rock masses in cold regions subjected to repeated freeze–thaw cycles can cause progressive deterioration in structural planes and rock mechanical properties,which significantly reduces the overall stability...Dangerous rock masses in cold regions subjected to repeated freeze–thaw cycles can cause progressive deterioration in structural planes and rock mechanical properties,which significantly reduces the overall stability and often triggers collapses or landslides.Existing studies focus mostly on singlescale or single-factor analyses but cannot fully capture the coupled mechanisms driving instability under freeze-thaw conditions.This study aimed to establish a theoretical framework to quantitatively characterize the evolution of rock mass stability,thereby providing a sound basis for hazard prediction and prevention.By integrating limit equilibrium theory with rock frost heave and circular hole expansion theory,mechanical models for sliding-and toppling-type dangerous rock masses were established.Three key factors were incorporated:frost heave forces acting on throughgoing structural planes,rock property deterioration in nonpenetrative sections,and progressive freezing depth development.A theoretical relationship between the stability coefficient and the number of freeze-thaw cycles was derived.By considering the Zimei Peaks rock masses in Gansu Province as the case study and conducting parametric analyses,the results revealed that the stability coefficient rapidly decreases during the initial cycles,followed by a slower decrease and eventual stabilization.The coefficient decreased 4.5 times more during the first 15 cycles than during the subsequent 15 cycles.Moreover,stability degradation was strongly influenced by the freezing temperature,initial porosity,and rock debris loss ratio,with critical thresholds determined at a 3.8%porosity and a 0.83 debris loss ratio.The findings indicated that stability deterioration is governed by the coupled effects of frost heave loading,microstructural damage accumulation,and freezing depth development,with clear stagedependent and threshold-driven patterns.This work provides not only a quantitative explanation of instability mechanisms in cold-region rock masses but also practical guidance for engineering stability assessment and disaster mitigation.展开更多
In the frost-thaw region,prolonged freezethaw weathering can induce fracture and weaken rock masses,threatening engineering stability.While interbedded rock masses are common in such projects,their failure mechanisms ...In the frost-thaw region,prolonged freezethaw weathering can induce fracture and weaken rock masses,threatening engineering stability.While interbedded rock masses are common in such projects,their failure mechanisms remain insufficiently investigated in freezing and thawing environments.Therefore,this research establishes a particle flow code(PFC2D)model of interlayered rock masses with particular emphasis on the role of thickness variation.The analysis focuses on displacement,crack evolution,contact forces,and uniaxial compressive strength.The findings indicate that:(i)Completing 8 freeze-thaw cycles significantly increases displacement and contact forces,with crack growth accelerating markedly after 16 cycles.As the soft rock layer thickness ratio(Hs/H)increases,the peak contact force decreases by 18.3%,while the number of cracks rises by 48%.Once Hs/H exceeded 0.5,the rate of crack development decelerates.This reflects progressive bond degradation and damage accumulation:microscopic bonds weaken and rupture to form microcracks.Increased soft rock thickness promotes micro-damage accumulation,altering contact forces and intensifying degradation.(ii)Compressive cracks predominantly initiate in soft rock(limestone).After 20 cycles,cracking extends into the hard rock regions.As the Hs/H rises,compressive cracks first increase and then decline,with an overall reduction of 10.8%,while the compressive contact force exhibits a consistent downward trend.This trend indicates that freeze-thaw cycles cause severe microscopic degradation in soft rock,weakening its macroscopic strength and influencing compressive crack development.Increased soft rock thickness alters the stress state,thereby modifying crack propagation.(iii)Uniaxial compressive strength experiences a marked deterioration after 15 freeze-thaw cycles.It follows an exponential decay with increasing Hs/H,culminating in a total strength reduction of 76.9%.This demonstrates that freeze-thaw-induced microscopic damage deteriorates interparticle cohesion,reducing rock mass strength.A higher Hs/H ratio accelerates microscopic damage in the soft rock,causing cohesion to decay nonlinearly and macroscopic strength to drop exponentially.These results provide a theoretical basis for assessing the deformation and failure behaviors of rock masses under cyclic freeze-thaw action.展开更多
The Standard Model of particle physics assumes that fundamental fermions are point particles with zero radius, no spatial dimensions, and infinite matter density. This alternative model treats the nine charged fundame...The Standard Model of particle physics assumes that fundamental fermions are point particles with zero radius, no spatial dimensions, and infinite matter density. This alternative model treats the nine charged fundamental fermions (three leptons and nine quarks) as spheres with non-zero holographic radius. Holographic analysis (based on quantum mechanics, general relativity, thermodynamics, and Shannon information theory) specifies electron mass by five fundamental constants: Planck’s constant ℏ, gravitational constant G, fine structure constant α, cosmological constant Λ, and vacuum energy fraction ΩΛ. Protons and neutrons are composite systems of up and down quarks. Describing forces between quark constituents confined within nucleons as inverse square attractive forces, this alternative model identifies composition factors Cpand Cnto relate proton and neutron masses to electron mass and thus to fundamental constants. An appendix summarizes holographic analyses characterizing astronomical masses at the opposite end of the mass scale for objects in the universe.展开更多
Pediatric liver masses encompass a diverse spectrum of benign and malignant lesions,with distinct patterns based on patient age.Optimal imaging is critical for timely diagnosis,management,and prognosis.This pictorial ...Pediatric liver masses encompass a diverse spectrum of benign and malignant lesions,with distinct patterns based on patient age.Optimal imaging is critical for timely diagnosis,management,and prognosis.This pictorial minireview cate-gorizes pediatric liver masses by age group to guide hepatology and radiology practice,with an emphasis on imaging characteristics.In children from birth to six years of age,the most common liver masses include hepatoblastoma,the most common primary hepatic malignancy in this age group;infantile hemangioma,a benign vascular tumor with a characteristic appearance on imaging;and mesen-chymal hamartoma,a rare developmental lesion.For children older than six years,liver masses are distinct,with hepatocellular carcinoma being the predo-minant malignant lesion.Benign masses such as focal nodular hyperplasia and hepatocellular adenoma also emerge in this age range,often linked to hormonal influences or metabolic disorders.The masses observed across all pediatric age groups include hepatic cysts,choledochal cysts,hydatid cysts,pyogenic and amebic abscesses,tuberculosis,lymphoma,and metastases,each presenting with unique imaging features essential for differential diagnosis.This minireview provides a comprehensive,age-based overview of pediatric liver masses,focusing on clinical presentation and key imaging findings to support accurate diagnosis and optimize management strategies in clinical hepatology,particularly in low resource settings.展开更多
The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the...The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary(PRE)region in winter 2021.The sum concentration of SOA tracers was 6.2–132.8 ng m^(−3),with SOAM and SOAI as the main components in both continental(scenarios A1 and A2)and marine air masses(scenario A3),as well as their combination(scenario A4).The highest and lowest levels of SOAM were observed in A1 and A3,respectively,which were mainly related to the variations in meteorological conditions,precursor concentrations,and the degree of photochemical processes.Higher MBTCA/HGA(3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid)ratios suggested a less significant contribution fromα-pinene to SOAM.The variations of SOAI in the different scenarios were associated with differences in relative humidity,particle acidity,and isoprene/NOx ratios.The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas,which was confirmed by the correlation among biogenic and anthropogenic precursors.The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes,with the highest concentrations in A1.A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25%to the total SOA at DWS,while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.展开更多
Cystic lesions of the anterior mediastinum in children suggest a well-known group of benign lesions that are comparatively frequent.Thymic cysts(TCs)are mostly positioned in the anterior mediastinum and some patients ...Cystic lesions of the anterior mediastinum in children suggest a well-known group of benign lesions that are comparatively frequent.Thymic cysts(TCs)are mostly positioned in the anterior mediastinum and some patients in the neck.Benign TCs classified as congenital intra-thoracic mesothelial cysts are commonly asymptomatic and have slight clinical significance.Multilocular TC,which can mimic another anterior mediastinal cystic tumor and is seen in adults,is more clinically important.It is a sporadic mediastinal lesion thought to arise in the course of acquired inflammation.Congenital mediastinal cysts represent 3%-6%of all mediastinal tumors and 10%-18%of radiologically reported mediastinal masses.Mediastinal TCs are uncommon and it is hard to know their true incidence.About 60%of cases with mediastinal TCs are asymptomatic,and the remainder of patients complains of nonspecific symptoms(e.g.,chest pain,dyspnea,or cough).The literature suggests that most cysts are benign,but an indefinite percentage may have a neoplastic process and result in significant compressive symptoms over time.Clinical symptoms of TCs vary depending on the location.In addition,frequent symptoms at the appearance of enlarged benign thymic and mediastinal cysts generally contain compressive symptoms(e.g.,respiratory distress,thymic pain,and symptoms related to Horner syndrome,hoarseness,dysphonia,dyspnea,orthopnea,wheezing,and fever).Many TCs have cystic density and a neat border and are simple to diagnose with radiological imaging.However,some TCs are hard to identify before surgery and may be misidentified as thymomas depending on their site and computed tomography results.Excision by thoracotomy,median sternotomy,or video-assisted techniques is essential for conclusive diagnosis,management,and abolition of relapse of anterior mediastinal masses and TCs.Histopathologic examination may be required after surgery.Considering the extent of the mass and the preliminary inability to make a definitive diagnosis,en bloc excision of the cyst was thought to be preferred to circumvent likely complications(e.g.,perforation,spillage of the contents,or incomplete excision).展开更多
Curtain grouting projects are characterized by their large scale and complexity,presenting significant challenges for real-time prediction of grout penetration using traditional methods.This study introduces an intell...Curtain grouting projects are characterized by their large scale and complexity,presenting significant challenges for real-time prediction of grout penetration using traditional methods.This study introduces an intelligent prediction method for grouting in fractured rock masses based on three core principles:integration of multi-source input features,fracture voxel modeling,and shortest path in sequential grouting.Three categories of data(geological structure data,grouting environmental data,and grouting operation data in the concept of a grouting geological model)are integrated and served as multi-source structured data in the intelligent prediction of grouting.A voxelization model quantifies the spatial characteristics of fractures,with voxel size optimized for capturing grouting paths.A shortest path algorithm based on a hierarchical solution is then developed to calculate grout penetration distances in the process of sequential grouting.A complete analysis framework is established,from the voxelization of the fracture network model to precise voxel classification,ultimately achieving an accurate prediction of grout penetration.The method demonstrates excellent performance on the test set,with validation against numerical methods in single-fracture and sequential grouting scenarios confirming its accuracy and prediction efficiency as hundreds of times faster than numerical methods.Application to the Dongzhuang hydraulic project’s grouting test area further validates its effectiveness in multi-hole grouting scenarios.展开更多
The property of water mass plays an important role in determining the distribution of phytoplankton in the ocean.In the Yellow Sea,summer stratification constrains water exchange and differentiates the properties of t...The property of water mass plays an important role in determining the distribution of phytoplankton in the ocean.In the Yellow Sea,summer stratification constrains water exchange and differentiates the properties of the Yellow Sea Cold Water Mass(YSCWM)and surface water,which in turn affects the spatiotemporal patterns of phytoplankton communities.Here,based on four summer cruises in the Yellow Sea,we examined the response of phytoplankton pigment assemblages to three water masses,including surface water(water massⅠ,WM-Ⅰ),thermocline water(WM-Ⅱ),and the YSCWM(WM-Ⅲ).Based on the opportunities for group dominance across the four cruises,Cyanophyceae,Haptophyceae,Chlorophyceae,and Cryptophyceae preferred living in WM-Ⅰ,characterized by relatively higher temperature and light intensity but lower nutrients;Bacillariophyceae,Chlorophyceae,Cyanophyceae,and Dinophyceae dominated in WM-Ⅲ,with relatively lower temperature and light intensity but higher nutrients.In comparison,the highest diversity of the dominant pigment groups was observed in WM-Ⅱ with intermediate temperature,light,and nutrient levels.The Dirichlet regression model identified the key environmental factors driving changes in phytoplankton assemblages in WM-Ⅰ,Ⅱ,and Ⅲ as dissolved inorganic phosphate(DIP),DIP and light,and temperature and ammonium,respectively.Under the impact of global environmental change,the fluctuations of key driving forces and their potential ecological implications need further investigation.展开更多
In geotechnical engineering applications,including mining and tunnel construction,the stability of fractured rock masses is paramount to ensuring structural safety.The spatial distribution and temporal evolution of in...In geotechnical engineering applications,including mining and tunnel construction,the stability of fractured rock masses is paramount to ensuring structural safety.The spatial distribution and temporal evolution of internal fractures fundamentally govern the mechanical behavior and failure mechanisms of rock masses.Nevertheless,the inherent complexity and structural concealment of rock mass systems pose significant challenges for the direct measurement of critical internal mechanical parameters.This study explores the use of deep learning to invert mechanical responses of NPR(Negative Poisson's Ratio)anchored fractured rock masses.Discrete Element Method(DEM)simulations were conducted to generate datasets including stress-strain curves and crack numbers under various initial fracture distributions.Three models—GRU,CNN+GRU,and CNN+GRU+ATT—were developed to predict rock mechanical parameters from NPR cable force data.Results show that the CNN+GRU+ATT model achieves superior accuracy,with R^(2)>0.90 and RMSE<5 on stress prediction tasks.It also accurately estimates initial crack quantity(np),with mean prediction error under 10%for high-fracture scenarios.The proposed model effectively captures stress fluctuations,offering early-warning potential for failure.The approach demonstrates strong generalization and robustness across varying crack configurations,providing a feasible framework for real-time health monitoring and mechanical parameter estimation in fractured rock engineering.展开更多
This study examines in-situ temperature profiles in three representative sections,namely,the Dalian-Chengshantou(DC),the Chengshantou-Changsangot(CC),and the 36°N,to delineate the interannual variations of the Ye...This study examines in-situ temperature profiles in three representative sections,namely,the Dalian-Chengshantou(DC),the Chengshantou-Changsangot(CC),and the 36°N,to delineate the interannual variations of the Yellow Sea Cold Water Mass(YSCWM)and investigate their potential connections,along with forcing factors,across different regions.The findings reveal the fol-lowing insights:1)The YSCWM experiences warming trends at DC,CC,and the western segment of the 36°N,revealing correspond-ing minimum temperature rates of 0.021℃/yr,0.043℃/yr,and 0.063℃/yr,respectively.Conversely,the eastern portion of the 36°N displays a slight cooling trend,resulting in a pronounced zonal disparity in long-term temperature trends.2)The changes in the YSCWM are closely linked to the atmospheric wind patterns.Notably,the weakening of northerly winds during winter corresponds to the rise in YSCWM temperature,which is accompanied by a westward shift in the cold core of the 36°N section.3)Correlation analysis with factors such as the Arctic Oscillation(AO),Pacific Decadal Oscillation(PDO),and El Niño-Southern Oscillation(EN-SO),etc.,indicates that changes in large-scale climate systems influence the spatiotemporal variations of the YSCWM,resulting in seasonal differences.展开更多
The special columnar jointed structure endows rocks with significant anisotropy,accurately grasping the strength and deformation properties of a columnar jointed rock mass(CJRM)under complex geological conditions is c...The special columnar jointed structure endows rocks with significant anisotropy,accurately grasping the strength and deformation properties of a columnar jointed rock mass(CJRM)under complex geological conditions is crucial for related engineering safety.Combined with the irregular jointed networks observed in the field,artificial irregular CJRM(ICJRM)samples with various inclination angles were prepared for triaxial tests.The results showed that the increase in confining pressure can enhance the ability of the ICJRM to resist deformation and failure,and reduce the deformation and strength anisotropic degrees.Considering the field stress situation,the engineering parts with an inclination angle of 30°−45°need to be taken seriously.Four typical failure modes were identified,and the sample with an inclination angle of 15°showed the same failure behavior as the field CJRM.Traditional and improved joint factor methods were used to establish empirical relationships for predicting the strength and deformation of CJRM under triaxial stress.Since the improved joint factor method can reflect the unique structure of CJRM,the predictive ability of the empirical relationship based on the improved method is better than that based on the traditional joint factor method.展开更多
The mechanical properties of jointed rock masses are critical to structural stability and durability.Advances in 3D printing and numerical simulations have facilitated innovative studies on their deformation and mecha...The mechanical properties of jointed rock masses are critical to structural stability and durability.Advances in 3D printing and numerical simulations have facilitated innovative studies on their deformation and mechanical behavior.However,the discontinuous and non-penetrating nature of rock joints presents challenges for predictive modeling.This study presents an computed tomography and synthetic rock mass(CT-SRM)integrated analytical approach to investigate the mechanical properties of non-persistent jointed coal measures,with three notable findings contributions:Firstly,a novel digital reconstruction methodology for joint networks was developed using high-precision CT scanning and 3D reconstruction techniques,achieving accuracy of 96.03%.Secondly,the research has identified the critical joint diameter effect(30 mm)causing 30%-50%strength reduction and observed wing-shaped deformation induced by 30°secondary joints,elucidating a new size-controlled mechanism.Thirdly,quantitative correlation models between joint geometric parameters and macroscopic mechanical properties were established,offering insights for engineering stability assessment.The developed analytical framework offers a reliable solution for stability prediction of jointed rock masses in engineering applications.展开更多
The rock masses in the hydro-fluctuation zone of reservoir banks sustain wettingdrying cycles(WDC),thereby affecting the stability of the reservoir bank slope.In this paper,rock masses with argillaceous siltstone and ...The rock masses in the hydro-fluctuation zone of reservoir banks sustain wettingdrying cycles(WDC),thereby affecting the stability of the reservoir bank slope.In this paper,rock masses with argillaceous siltstone and silty mudstone interbedded in Badong Formation were taken as the research object to investigate the variation of strength parameters of soft and hard interbedded rock masses with WDC and dip angle through laboratory experiments and numerical experiments.Some attempts were made to reveal the mechanical properties deterioration mechanism of interbedded rock masses by quantitatively analyzing the contribution of strength parameters deterioration of hard rocks,soft rocks,and bedding planes to the strength parameters deterioration of rock masses.The results indicate that the logarithmic function could be used to describe the deterioration of each strength parameter of both argillaceous siltstone and silty mudstone and bedding plane with the number of WDC.The strength parameters of interbedded rock masses decrease as the number of WDC increases,with the largest decrease after the first cycle and then slowing down in the later cycles.The strength parameters initially decrease and then increase as the dip angles increase.The impact of deteriorated strength parameters of bedding planes and rocks on the deterioration of strength parameters of interbedded rock masses differs significantly with the dip angle,which can be divided into four typical ranges of different controlling factors.展开更多
Joints are widely distributed structural defects in rock masses,and their geometric characteristics play a decisive role in the overall stability of rocks under complex stress conditions.To clarify the influence of jo...Joints are widely distributed structural defects in rock masses,and their geometric characteristics play a decisive role in the overall stability of rocks under complex stress conditions.To clarify the influence of joint geometry on the mechanical behavior of jointed rock under such conditions,this study investigated the mechanical properties and failure mechanisms of composite jointed rock specimens with varying joint roughness and joint dip angles.Three typical failure modes under triaxial loading were identified,and a mechanical analysis model incorporating joint roughness and dip angle was established.The failure mechanism was revealed,and a discrete element model was developed to analyze the micro-damage evolution process of the specimens.The results show that the mechanical parameters of the specimens exhibit pronounced anisotropy.Both the elastic modulus and peak strength reach their minimum values at a joint dip angle of 60°.Increasing joint roughness significantly reduces the degree of anisotropy and enhances the energy storage capacity of the specimens.A strong linear relationship is observed between the elastic strain energy and the peak deviatoric stress,confirming the applicability of the linear energy storage law in composite jointed rocks.Discrete element simulations revealed the evolution path and dominant types of microcracks between the joint and matrix.The joint dip angle governs the transition of dominant crack types from tensile to shear and then back to tensile.Increased joint roughness significantly suppresses damage localization along the joint and results in an approximately 20%increase in the proportion of shear microcracks within the matrix.These findings clarify the regulatory role of joint geometrical parameters in the damage evolution process.展开更多
The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across divers...The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across diverse geological settings.Large-scale models(LSMs),with vast parameter spaces and extensive training datasets,excel in solving complex visual problems.This study explores the potential of using one such LSM,Segment anything model(SAM),to identify facet-type discontinuities across several outcrops via interactive prompting.The findings demonstrate that SAM effectively segments two-dimensional(2D)discontinuities,with its generalization capability validated on a dataset of 2426 identified discontinuities across 170 outcrops.The model achieves 0.78 mean IoU and 0.86 average precision using 11-point prompts.To extend to three dimensions(3D),a framework integrating SAM with Structure-from-Motion(SfM)was proposed.By utilizing the inherent but often overlooked relationship between image pixels and point clouds in SfM,the identification process was simplified and generalized across photogrammetric devices.Benchmark studies showed that the framework achieved 0.91 average precision,identifying 87 discontinuities in Dataset-3D.The results confirm its high precision and efficiency,making it a valuable tool for data annotation.The proposed method offers a practical solution for geological investigations.展开更多
The temperature and salinity distributions, and the water mass structures in Northwest Pacific Ocean are studied using the temperature and salinity data obtained by Argo profiling floats. The T-S relation in this regi...The temperature and salinity distributions, and the water mass structures in Northwest Pacific Ocean are studied using the temperature and salinity data obtained by Argo profiling floats. The T-S relation in this region indicates there exist 8 water masses, they are the North Pacific Tropical Surface Water （NPTSW）, North P, acific Subsurface Water （NPSSW）, North Pacific Intermediate Water （NPIW）, North Pacific Subtropical Water （NPSTW）, North Pacific Deep Water （NPDW） and Equatorial Surface Water （ESW）, and the South Pacific Subsurface Water （SPSSW） and South Pacific Intermediate Water （SPIW）.展开更多
Seasonal variations of water masses in the East China Sea(ECS) and adjacent areas are investigated, based on historical data of temperature and salinity( T-S). Dynamic and thermodynamic mechanisms that affect seasonal...Seasonal variations of water masses in the East China Sea(ECS) and adjacent areas are investigated, based on historical data of temperature and salinity( T-S). Dynamic and thermodynamic mechanisms that affect seasonal variations of some dominant water masses are discussed, with reference to meteorological data. In the ECS above depth 600 m, there are eight water masses in summer but only five in winter. Among these, Kuroshio Surface Water(KSW), Kuroshio Intermediate Water(KIW), ECS Surface Water(ECSSW), Continental Coastal Water(CCW), and Yellow Sea Surface Water(YSSW) exist throughout the year. Kuroshio Subsurface Water(KSSW), ECS Deep Water(ECSDW), and Yellow Sea Bottom Water(YSBW) are all seasonal water masses, occurring from May through October. The CCW, ECSSW and KSW all have significant seasonal variations, both in their horizontal and vertical extents and their T-S properties. Wind stress, the Kuroshio and its branch currents, and coastal currents are dynamic factors for seasonal variation in spatial extent of the CCW, KSW, and ECSSW, whereas sea surface heat and freshwater fl uxes are thermodynamic factors for seasonal variations of T-S properties and thickness of these water masses. In addition, the CCW is affected by river runoff and ECSSW by the CCW and KSW.展开更多
Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subj...Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subjected to seepage. The radial stress distribution curve, ground reaction curve, and relation curve between plastic softening region radius and supporting force in three different conditions were drawn respectively. From the comparisons among these results for different conditions, it is found that when the supporting force is the same, the displacement of tunnel wall considering both seepage and strain softening is 85.71% greater than that only considering seepage. The increase values of radial displacement at 0.95 m and plastic softening region radius at 6.6 m show that the seepage and strain softening have the most unfavorable effects on circular opening stability in strain softening rock masses.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42107211 and U23A20651)the Natural Science Foundation of Sichuan Province(No.2025ZNSFSC0097)。
文摘Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These rock masses are predominantly composed of sedimentary,para-metamorphic,and volcanic rock types,characterized by a set of prominent,primary bedding structural planes(layers)exhibiting relatively consistent orientations and significant spatial continuity.
基金the financial support provided by the Major Science and Technology Project of Xinjiang Uygur Autonomous Region(Grant NO.2024A01003)the National Natural Science Foundation of China(Grant NO.51508556)+3 种基金the Key Support Project of the National Natural Science Foundation of China Joint Fund(Grant No.U24B2039)the Natural Science Foundation of Jiangxi Province(Grant NO.20232BAB203079,20224BAB213045)Program of China Scholarship Council(Grant NO.202406430056)the Fundamental Research Funds for the Central Universities(Ph.D.Top Innovative Talents Fund of CUMTB)(Grant NO.BBJ2025081)。
文摘Dangerous rock masses in cold regions subjected to repeated freeze–thaw cycles can cause progressive deterioration in structural planes and rock mechanical properties,which significantly reduces the overall stability and often triggers collapses or landslides.Existing studies focus mostly on singlescale or single-factor analyses but cannot fully capture the coupled mechanisms driving instability under freeze-thaw conditions.This study aimed to establish a theoretical framework to quantitatively characterize the evolution of rock mass stability,thereby providing a sound basis for hazard prediction and prevention.By integrating limit equilibrium theory with rock frost heave and circular hole expansion theory,mechanical models for sliding-and toppling-type dangerous rock masses were established.Three key factors were incorporated:frost heave forces acting on throughgoing structural planes,rock property deterioration in nonpenetrative sections,and progressive freezing depth development.A theoretical relationship between the stability coefficient and the number of freeze-thaw cycles was derived.By considering the Zimei Peaks rock masses in Gansu Province as the case study and conducting parametric analyses,the results revealed that the stability coefficient rapidly decreases during the initial cycles,followed by a slower decrease and eventual stabilization.The coefficient decreased 4.5 times more during the first 15 cycles than during the subsequent 15 cycles.Moreover,stability degradation was strongly influenced by the freezing temperature,initial porosity,and rock debris loss ratio,with critical thresholds determined at a 3.8%porosity and a 0.83 debris loss ratio.The findings indicated that stability deterioration is governed by the coupled effects of frost heave loading,microstructural damage accumulation,and freezing depth development,with clear stagedependent and threshold-driven patterns.This work provides not only a quantitative explanation of instability mechanisms in cold-region rock masses but also practical guidance for engineering stability assessment and disaster mitigation.
基金supported by the National Natural Science Foundation of China(Grant Nos.52379100 and 42462030)。
文摘In the frost-thaw region,prolonged freezethaw weathering can induce fracture and weaken rock masses,threatening engineering stability.While interbedded rock masses are common in such projects,their failure mechanisms remain insufficiently investigated in freezing and thawing environments.Therefore,this research establishes a particle flow code(PFC2D)model of interlayered rock masses with particular emphasis on the role of thickness variation.The analysis focuses on displacement,crack evolution,contact forces,and uniaxial compressive strength.The findings indicate that:(i)Completing 8 freeze-thaw cycles significantly increases displacement and contact forces,with crack growth accelerating markedly after 16 cycles.As the soft rock layer thickness ratio(Hs/H)increases,the peak contact force decreases by 18.3%,while the number of cracks rises by 48%.Once Hs/H exceeded 0.5,the rate of crack development decelerates.This reflects progressive bond degradation and damage accumulation:microscopic bonds weaken and rupture to form microcracks.Increased soft rock thickness promotes micro-damage accumulation,altering contact forces and intensifying degradation.(ii)Compressive cracks predominantly initiate in soft rock(limestone).After 20 cycles,cracking extends into the hard rock regions.As the Hs/H rises,compressive cracks first increase and then decline,with an overall reduction of 10.8%,while the compressive contact force exhibits a consistent downward trend.This trend indicates that freeze-thaw cycles cause severe microscopic degradation in soft rock,weakening its macroscopic strength and influencing compressive crack development.Increased soft rock thickness alters the stress state,thereby modifying crack propagation.(iii)Uniaxial compressive strength experiences a marked deterioration after 15 freeze-thaw cycles.It follows an exponential decay with increasing Hs/H,culminating in a total strength reduction of 76.9%.This demonstrates that freeze-thaw-induced microscopic damage deteriorates interparticle cohesion,reducing rock mass strength.A higher Hs/H ratio accelerates microscopic damage in the soft rock,causing cohesion to decay nonlinearly and macroscopic strength to drop exponentially.These results provide a theoretical basis for assessing the deformation and failure behaviors of rock masses under cyclic freeze-thaw action.
文摘The Standard Model of particle physics assumes that fundamental fermions are point particles with zero radius, no spatial dimensions, and infinite matter density. This alternative model treats the nine charged fundamental fermions (three leptons and nine quarks) as spheres with non-zero holographic radius. Holographic analysis (based on quantum mechanics, general relativity, thermodynamics, and Shannon information theory) specifies electron mass by five fundamental constants: Planck’s constant ℏ, gravitational constant G, fine structure constant α, cosmological constant Λ, and vacuum energy fraction ΩΛ. Protons and neutrons are composite systems of up and down quarks. Describing forces between quark constituents confined within nucleons as inverse square attractive forces, this alternative model identifies composition factors Cpand Cnto relate proton and neutron masses to electron mass and thus to fundamental constants. An appendix summarizes holographic analyses characterizing astronomical masses at the opposite end of the mass scale for objects in the universe.
文摘Pediatric liver masses encompass a diverse spectrum of benign and malignant lesions,with distinct patterns based on patient age.Optimal imaging is critical for timely diagnosis,management,and prognosis.This pictorial minireview cate-gorizes pediatric liver masses by age group to guide hepatology and radiology practice,with an emphasis on imaging characteristics.In children from birth to six years of age,the most common liver masses include hepatoblastoma,the most common primary hepatic malignancy in this age group;infantile hemangioma,a benign vascular tumor with a characteristic appearance on imaging;and mesen-chymal hamartoma,a rare developmental lesion.For children older than six years,liver masses are distinct,with hepatocellular carcinoma being the predo-minant malignant lesion.Benign masses such as focal nodular hyperplasia and hepatocellular adenoma also emerge in this age range,often linked to hormonal influences or metabolic disorders.The masses observed across all pediatric age groups include hepatic cysts,choledochal cysts,hydatid cysts,pyogenic and amebic abscesses,tuberculosis,lymphoma,and metastases,each presenting with unique imaging features essential for differential diagnosis.This minireview provides a comprehensive,age-based overview of pediatric liver masses,focusing on clinical presentation and key imaging findings to support accurate diagnosis and optimize management strategies in clinical hepatology,particularly in low resource settings.
基金supported by the State Key Program of the National Natural Science Foundation of China(Grant Nos.42230701,91644215)the National Natural ScienceFoundation of China(Grant Nos.42122062 and 42307137)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022A1515010852)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.23hytd002)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2023SP218)L.M.acknowledges the Zhuhai Science and Technology Plan Project(Grant No.ZH22036201210115PWC).
文摘The compositions and distributions of monoterpenes,isoprene,aromatics and sesquiterpene SOA tracers(SOAM,SOAI,SOAA and SOAS,respectively)at an island site(Da Wan Shan Island,DWS)were investigated in the context of the influence of continental and marine air masses over the Pearl River Estuary(PRE)region in winter 2021.The sum concentration of SOA tracers was 6.2–132.8 ng m^(−3),with SOAM and SOAI as the main components in both continental(scenarios A1 and A2)and marine air masses(scenario A3),as well as their combination(scenario A4).The highest and lowest levels of SOAM were observed in A1 and A3,respectively,which were mainly related to the variations in meteorological conditions,precursor concentrations,and the degree of photochemical processes.Higher MBTCA/HGA(3-methyl-1,2,3-butanetricarboxylic acid/3-hydroxyglutaric acid)ratios suggested a less significant contribution fromα-pinene to SOAM.The variations of SOAI in the different scenarios were associated with differences in relative humidity,particle acidity,and isoprene/NOx ratios.The respective highest and lowest concentrations of aromatics SOA tracers in A1 and A3 revealed the influence of anthropogenic precursors from upwind continental areas,which was confirmed by the correlation among biogenic and anthropogenic precursors.The results of the tracer-based-method suggested dominant contributions of SOAs from aromatics and monoterpenes,with the highest concentrations in A1.A WRF-Chem simulation revealed that the SOAs from the above precursors only contributed 12%–25%to the total SOA at DWS,while the spatial distributions of SOAs further highlighted that the abundance of SOAs over the PRE region in winter is highly associated with air masses transported from upwind continental areas.
文摘Cystic lesions of the anterior mediastinum in children suggest a well-known group of benign lesions that are comparatively frequent.Thymic cysts(TCs)are mostly positioned in the anterior mediastinum and some patients in the neck.Benign TCs classified as congenital intra-thoracic mesothelial cysts are commonly asymptomatic and have slight clinical significance.Multilocular TC,which can mimic another anterior mediastinal cystic tumor and is seen in adults,is more clinically important.It is a sporadic mediastinal lesion thought to arise in the course of acquired inflammation.Congenital mediastinal cysts represent 3%-6%of all mediastinal tumors and 10%-18%of radiologically reported mediastinal masses.Mediastinal TCs are uncommon and it is hard to know their true incidence.About 60%of cases with mediastinal TCs are asymptomatic,and the remainder of patients complains of nonspecific symptoms(e.g.,chest pain,dyspnea,or cough).The literature suggests that most cysts are benign,but an indefinite percentage may have a neoplastic process and result in significant compressive symptoms over time.Clinical symptoms of TCs vary depending on the location.In addition,frequent symptoms at the appearance of enlarged benign thymic and mediastinal cysts generally contain compressive symptoms(e.g.,respiratory distress,thymic pain,and symptoms related to Horner syndrome,hoarseness,dysphonia,dyspnea,orthopnea,wheezing,and fever).Many TCs have cystic density and a neat border and are simple to diagnose with radiological imaging.However,some TCs are hard to identify before surgery and may be misidentified as thymomas depending on their site and computed tomography results.Excision by thoracotomy,median sternotomy,or video-assisted techniques is essential for conclusive diagnosis,management,and abolition of relapse of anterior mediastinal masses and TCs.Histopathologic examination may be required after surgery.Considering the extent of the mass and the preliminary inability to make a definitive diagnosis,en bloc excision of the cyst was thought to be preferred to circumvent likely complications(e.g.,perforation,spillage of the contents,or incomplete excision).
基金supported by the National Natural Science Foundation of China(Grant No.U23A6018)Science and Technology Program of Hebei(Grant No.E2022202041,2022HBQZYCXY004,242Q9920Z)the project of“Key technologies of seepage control system for large-scale hydraulic projects”was also gratefully appreciated.
文摘Curtain grouting projects are characterized by their large scale and complexity,presenting significant challenges for real-time prediction of grout penetration using traditional methods.This study introduces an intelligent prediction method for grouting in fractured rock masses based on three core principles:integration of multi-source input features,fracture voxel modeling,and shortest path in sequential grouting.Three categories of data(geological structure data,grouting environmental data,and grouting operation data in the concept of a grouting geological model)are integrated and served as multi-source structured data in the intelligent prediction of grouting.A voxelization model quantifies the spatial characteristics of fractures,with voxel size optimized for capturing grouting paths.A shortest path algorithm based on a hierarchical solution is then developed to calculate grout penetration distances in the process of sequential grouting.A complete analysis framework is established,from the voxelization of the fracture network model to precise voxel classification,ultimately achieving an accurate prediction of grout penetration.The method demonstrates excellent performance on the test set,with validation against numerical methods in single-fracture and sequential grouting scenarios confirming its accuracy and prediction efficiency as hundreds of times faster than numerical methods.Application to the Dongzhuang hydraulic project’s grouting test area further validates its effectiveness in multi-hole grouting scenarios.
基金Supported by the National Natural Science Foundation of China(No.42030402)the Program of Shanghai Subject Chief Scientist(No.23XD1401200)collected onboard of R/Vs Dongfanghong 2 and Lanhai 101 implementing the open research cruises(Cruise Nos.NORC 2013-01,NORC 2015-01,NORC 2018-01,NORC 2021-01)supported by NSFC Shiptime Sharing Project(Nos.41249901,41449901,41749901,42049901)。
文摘The property of water mass plays an important role in determining the distribution of phytoplankton in the ocean.In the Yellow Sea,summer stratification constrains water exchange and differentiates the properties of the Yellow Sea Cold Water Mass(YSCWM)and surface water,which in turn affects the spatiotemporal patterns of phytoplankton communities.Here,based on four summer cruises in the Yellow Sea,we examined the response of phytoplankton pigment assemblages to three water masses,including surface water(water massⅠ,WM-Ⅰ),thermocline water(WM-Ⅱ),and the YSCWM(WM-Ⅲ).Based on the opportunities for group dominance across the four cruises,Cyanophyceae,Haptophyceae,Chlorophyceae,and Cryptophyceae preferred living in WM-Ⅰ,characterized by relatively higher temperature and light intensity but lower nutrients;Bacillariophyceae,Chlorophyceae,Cyanophyceae,and Dinophyceae dominated in WM-Ⅲ,with relatively lower temperature and light intensity but higher nutrients.In comparison,the highest diversity of the dominant pigment groups was observed in WM-Ⅱ with intermediate temperature,light,and nutrient levels.The Dirichlet regression model identified the key environmental factors driving changes in phytoplankton assemblages in WM-Ⅰ,Ⅱ,and Ⅲ as dissolved inorganic phosphate(DIP),DIP and light,and temperature and ammonium,respectively.Under the impact of global environmental change,the fluctuations of key driving forces and their potential ecological implications need further investigation.
基金supported by State Key Laboratory for Tunnel Engineering(TESKL202425)the National Natural Science Foundation of China(Grant Nos.U24A2085,52174096,52304110)+1 种基金the Henan Province Key Research and Development Program(Grant Nos.241111322000)the Henan Provincial Science and Technology Research Project(Grant Nos.252102320020)。
文摘In geotechnical engineering applications,including mining and tunnel construction,the stability of fractured rock masses is paramount to ensuring structural safety.The spatial distribution and temporal evolution of internal fractures fundamentally govern the mechanical behavior and failure mechanisms of rock masses.Nevertheless,the inherent complexity and structural concealment of rock mass systems pose significant challenges for the direct measurement of critical internal mechanical parameters.This study explores the use of deep learning to invert mechanical responses of NPR(Negative Poisson's Ratio)anchored fractured rock masses.Discrete Element Method(DEM)simulations were conducted to generate datasets including stress-strain curves and crack numbers under various initial fracture distributions.Three models—GRU,CNN+GRU,and CNN+GRU+ATT—were developed to predict rock mechanical parameters from NPR cable force data.Results show that the CNN+GRU+ATT model achieves superior accuracy,with R^(2)>0.90 and RMSE<5 on stress prediction tasks.It also accurately estimates initial crack quantity(np),with mean prediction error under 10%for high-fracture scenarios.The proposed model effectively captures stress fluctuations,offering early-warning potential for failure.The approach demonstrates strong generalization and robustness across varying crack configurations,providing a feasible framework for real-time health monitoring and mechanical parameter estimation in fractured rock engineering.
文摘This study examines in-situ temperature profiles in three representative sections,namely,the Dalian-Chengshantou(DC),the Chengshantou-Changsangot(CC),and the 36°N,to delineate the interannual variations of the Yellow Sea Cold Water Mass(YSCWM)and investigate their potential connections,along with forcing factors,across different regions.The findings reveal the fol-lowing insights:1)The YSCWM experiences warming trends at DC,CC,and the western segment of the 36°N,revealing correspond-ing minimum temperature rates of 0.021℃/yr,0.043℃/yr,and 0.063℃/yr,respectively.Conversely,the eastern portion of the 36°N displays a slight cooling trend,resulting in a pronounced zonal disparity in long-term temperature trends.2)The changes in the YSCWM are closely linked to the atmospheric wind patterns.Notably,the weakening of northerly winds during winter corresponds to the rise in YSCWM temperature,which is accompanied by a westward shift in the cold core of the 36°N section.3)Correlation analysis with factors such as the Arctic Oscillation(AO),Pacific Decadal Oscillation(PDO),and El Niño-Southern Oscillation(EN-SO),etc.,indicates that changes in large-scale climate systems influence the spatiotemporal variations of the YSCWM,resulting in seasonal differences.
基金Projects(42307192,41831278)supported by the National Natural Science Foundation of ChinaProject(CKWV20231175/KY)supported by the CRSRI Open Research Program,China。
文摘The special columnar jointed structure endows rocks with significant anisotropy,accurately grasping the strength and deformation properties of a columnar jointed rock mass(CJRM)under complex geological conditions is crucial for related engineering safety.Combined with the irregular jointed networks observed in the field,artificial irregular CJRM(ICJRM)samples with various inclination angles were prepared for triaxial tests.The results showed that the increase in confining pressure can enhance the ability of the ICJRM to resist deformation and failure,and reduce the deformation and strength anisotropic degrees.Considering the field stress situation,the engineering parts with an inclination angle of 30°−45°need to be taken seriously.Four typical failure modes were identified,and the sample with an inclination angle of 15°showed the same failure behavior as the field CJRM.Traditional and improved joint factor methods were used to establish empirical relationships for predicting the strength and deformation of CJRM under triaxial stress.Since the improved joint factor method can reflect the unique structure of CJRM,the predictive ability of the empirical relationship based on the improved method is better than that based on the traditional joint factor method.
基金financially supported by the Hubei Province Key R&D Plan Project"Sliding Mechanism and Multi-indicator Linkage Process Prediction of Landslides in the West of Hubei Province"(No.2023BCB117)。
文摘The mechanical properties of jointed rock masses are critical to structural stability and durability.Advances in 3D printing and numerical simulations have facilitated innovative studies on their deformation and mechanical behavior.However,the discontinuous and non-penetrating nature of rock joints presents challenges for predictive modeling.This study presents an computed tomography and synthetic rock mass(CT-SRM)integrated analytical approach to investigate the mechanical properties of non-persistent jointed coal measures,with three notable findings contributions:Firstly,a novel digital reconstruction methodology for joint networks was developed using high-precision CT scanning and 3D reconstruction techniques,achieving accuracy of 96.03%.Secondly,the research has identified the critical joint diameter effect(30 mm)causing 30%-50%strength reduction and observed wing-shaped deformation induced by 30°secondary joints,elucidating a new size-controlled mechanism.Thirdly,quantitative correlation models between joint geometric parameters and macroscopic mechanical properties were established,offering insights for engineering stability assessment.The developed analytical framework offers a reliable solution for stability prediction of jointed rock masses in engineering applications.
基金supported by the Chinese National Key R&D Program(No.2022YFC3080200)the Chinese National Natural Science Foundation(No.42090054)。
文摘The rock masses in the hydro-fluctuation zone of reservoir banks sustain wettingdrying cycles(WDC),thereby affecting the stability of the reservoir bank slope.In this paper,rock masses with argillaceous siltstone and silty mudstone interbedded in Badong Formation were taken as the research object to investigate the variation of strength parameters of soft and hard interbedded rock masses with WDC and dip angle through laboratory experiments and numerical experiments.Some attempts were made to reveal the mechanical properties deterioration mechanism of interbedded rock masses by quantitatively analyzing the contribution of strength parameters deterioration of hard rocks,soft rocks,and bedding planes to the strength parameters deterioration of rock masses.The results indicate that the logarithmic function could be used to describe the deterioration of each strength parameter of both argillaceous siltstone and silty mudstone and bedding plane with the number of WDC.The strength parameters of interbedded rock masses decrease as the number of WDC increases,with the largest decrease after the first cycle and then slowing down in the later cycles.The strength parameters initially decrease and then increase as the dip angles increase.The impact of deteriorated strength parameters of bedding planes and rocks on the deterioration of strength parameters of interbedded rock masses differs significantly with the dip angle,which can be divided into four typical ranges of different controlling factors.
基金supported by the National Natural Science Foundation of China(Nos.52304108,52274148)China University of Mining and Technology-Beijing Undergraduate Innovation Training Program(No.202515011).
文摘Joints are widely distributed structural defects in rock masses,and their geometric characteristics play a decisive role in the overall stability of rocks under complex stress conditions.To clarify the influence of joint geometry on the mechanical behavior of jointed rock under such conditions,this study investigated the mechanical properties and failure mechanisms of composite jointed rock specimens with varying joint roughness and joint dip angles.Three typical failure modes under triaxial loading were identified,and a mechanical analysis model incorporating joint roughness and dip angle was established.The failure mechanism was revealed,and a discrete element model was developed to analyze the micro-damage evolution process of the specimens.The results show that the mechanical parameters of the specimens exhibit pronounced anisotropy.Both the elastic modulus and peak strength reach their minimum values at a joint dip angle of 60°.Increasing joint roughness significantly reduces the degree of anisotropy and enhances the energy storage capacity of the specimens.A strong linear relationship is observed between the elastic strain energy and the peak deviatoric stress,confirming the applicability of the linear energy storage law in composite jointed rocks.Discrete element simulations revealed the evolution path and dominant types of microcracks between the joint and matrix.The joint dip angle governs the transition of dominant crack types from tensile to shear and then back to tensile.Increased joint roughness significantly suppresses damage localization along the joint and results in an approximately 20%increase in the proportion of shear microcracks within the matrix.These findings clarify the regulatory role of joint geometrical parameters in the damage evolution process.
基金support in dataset preparation.This study was funded by National Natural Science Foundation of China(Nos.42422704 and 52379109)Opening the fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(No.SKLGP2024K028)Science and Technology Research and Design Projects of China State Construction Engineering Corporation Ltd.(No.CSCEC-2024-Q-68).
文摘The identification of rock mass discontinuities is critical for rock mass characterization.While high-resolution digital outcrop models(DOMs)are widely used,current digital methods struggle to generalize across diverse geological settings.Large-scale models(LSMs),with vast parameter spaces and extensive training datasets,excel in solving complex visual problems.This study explores the potential of using one such LSM,Segment anything model(SAM),to identify facet-type discontinuities across several outcrops via interactive prompting.The findings demonstrate that SAM effectively segments two-dimensional(2D)discontinuities,with its generalization capability validated on a dataset of 2426 identified discontinuities across 170 outcrops.The model achieves 0.78 mean IoU and 0.86 average precision using 11-point prompts.To extend to three dimensions(3D),a framework integrating SAM with Structure-from-Motion(SfM)was proposed.By utilizing the inherent but often overlooked relationship between image pixels and point clouds in SfM,the identification process was simplified and generalized across photogrammetric devices.Benchmark studies showed that the framework achieved 0.91 average precision,identifying 87 discontinuities in Dataset-3D.The results confirm its high precision and efficiency,making it a valuable tool for data annotation.The proposed method offers a practical solution for geological investigations.
基金the specical scientific research project for the welfare of the State Oceanic Administration for 2007.(No.200706022).
文摘The temperature and salinity distributions, and the water mass structures in Northwest Pacific Ocean are studied using the temperature and salinity data obtained by Argo profiling floats. The T-S relation in this region indicates there exist 8 water masses, they are the North Pacific Tropical Surface Water （NPTSW）, North P, acific Subsurface Water （NPSSW）, North Pacific Intermediate Water （NPIW）, North Pacific Subtropical Water （NPSTW）, North Pacific Deep Water （NPDW） and Equatorial Surface Water （ESW）, and the South Pacific Subsurface Water （SPSSW） and South Pacific Intermediate Water （SPIW）.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences(CAS)(No.KZCX2-EW-209)the CAS Strategy Pioneering Program(Nos.XDA10020104,XDA10020305)the State Oceanic Administration(SOA)Global Change and Air-Sea Interaction Program
文摘Seasonal variations of water masses in the East China Sea(ECS) and adjacent areas are investigated, based on historical data of temperature and salinity( T-S). Dynamic and thermodynamic mechanisms that affect seasonal variations of some dominant water masses are discussed, with reference to meteorological data. In the ECS above depth 600 m, there are eight water masses in summer but only five in winter. Among these, Kuroshio Surface Water(KSW), Kuroshio Intermediate Water(KIW), ECS Surface Water(ECSSW), Continental Coastal Water(CCW), and Yellow Sea Surface Water(YSSW) exist throughout the year. Kuroshio Subsurface Water(KSSW), ECS Deep Water(ECSDW), and Yellow Sea Bottom Water(YSBW) are all seasonal water masses, occurring from May through October. The CCW, ECSSW and KSW all have significant seasonal variations, both in their horizontal and vertical extents and their T-S properties. Wind stress, the Kuroshio and its branch currents, and coastal currents are dynamic factors for seasonal variation in spatial extent of the CCW, KSW, and ECSSW, whereas sea surface heat and freshwater fl uxes are thermodynamic factors for seasonal variations of T-S properties and thickness of these water masses. In addition, the CCW is affected by river runoff and ECSSW by the CCW and KSW.
基金Project(09JJ1008) supported by Hunan Provincial Science Foundation of ChinaProject(200550) supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China
文摘Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subjected to seepage. The radial stress distribution curve, ground reaction curve, and relation curve between plastic softening region radius and supporting force in three different conditions were drawn respectively. From the comparisons among these results for different conditions, it is found that when the supporting force is the same, the displacement of tunnel wall considering both seepage and strain softening is 85.71% greater than that only considering seepage. The increase values of radial displacement at 0.95 m and plastic softening region radius at 6.6 m show that the seepage and strain softening have the most unfavorable effects on circular opening stability in strain softening rock masses.
