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Large post-liquefaction deformation of sand:Mechanisms and modeling considering water absorption in shearing and seismic wave conditions

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Underground Space 2024年第5期18卷 3-64页

作者： Jian-Min Zhang Rui Wang Department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua UniversityBeijing 100084China

Large deformation of sand due to soil liquefaction is a major cause for seismic *** this study,the mechanisms and modeling of large post-liquefaction deformation of sand considering the significant influence of water absorption in shearing and seismic wave *** of case histories from past earthquakes and review of existing studies highlight the importance of the two *** on the micro and macro scale mechanisms for post-liquefaction shear deformation,the mechanism for water absorption in shearing after initial liquefaction is *** is aided by novel designed constant water-absorption-rate shear *** absorption in shearing can be classified into three types,including partial water absorption,complete water absorption,and compulsory water *** the influence of water absorption in shearing,even a strongly dilative sand under naturally drained conditions could experience instability and large shear *** mechanism for amplification of post-liquefaction deformation under surface wave load is also explained via element tests and theoretical *** shows that surface wave–shear wave coupling can induce asymmetrical force and resistance in sand,resulting in asymmetrical accumulation of deformation,which is amplified by liquefaction.A constitutive model,referred to as CycLiq,is formulated to capture the large deformation of sand considering water absorption in shearing and seismic wave conditions,along with its numerical implementation *** model is comprehensively calibrated based on various types of element tests and validated against centrifuge shaking table tests in the liquefaction experiments and analysis projects(LEAP).The model,along with various numerical analysis methods,is adopted in the successful simulation of water absorption in shearing and Rayleigh wave-shear wave coupling induced large liquefaction ***,the model is applied to high-performance simulation fo

关键词： Liquefaction Sand Large deformation Water absorption in shearing Surface wave Rayleigh wave-shear wave coupling

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An assumed enhanced strain finite element framework for tensile fracturing processes with dual-mechanism failure in transversely isotropic rocks

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Journal of Rock Mechanics and Geotechnical engineering 2025年第3期17卷 1474-1488页

作者： Yang Zhao Rui Wang Jian-Min Zhang State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing100084China

We present an assumed enhanced strain finite element framework for the simulation of tensile fracturing processes in transversely isotropic *** along the weak bedding planes and through the anisotropic rock matrix are treated with distinct enrichment,and a recently proposed dualmechanism tensile failure criterion for transversely isotropic rocks is adopted to determine crack initiation for the two failure *** cohesive crack model is adopted to characterize the response of embedded *** for the numerical implementation of the proposed framework,both algorithms for the update of local history variables at Gauss points and of the global finite element system are *** boundary-value problem simulations are carried out with the proposed framework,including uniaxial tension tests of Argillite,pre-notched square loaded in tension,three-point bending tests on Longmaxi shale,and simulations of tensile cracks induced by a strip load around a tunnel in transversely isotropic *** results reveal that the proposed framework can properly capture the tensile strength anisotropy and the anisotropic evolution of tensile cracks in transversely isotropic rocks.

关键词： Tensile fracture Assumed enhanced strain finite element Three-point bending test transversely isotropic rock Tensile failure criterion

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A semi-analytical model of the velocity profile for a conduit-multilayer matrix system

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Journal of Rock Mechanics and Geotechnical engineering 2025年第2期17卷 915-930页

作者： Shuai Zhang Xiaoli Liu Enzhi Wang State Key Laboratory of Hydroscience and Engineering Key Laboratory of Hydrosphere Sciences of the Ministry of Water Resourcesand Department of Hydraulic EngineeringTsinghua UniversityBeijing100084China

The flow field characteristics of the conduit-matrix system(CMS)have consistently been a primary area of interest to ***,under the long-term influence of water flow,the hydraulic conductivity of the matrix surrounding the conduit often deforms differentially along the conduit axis,resulting in the development of a conduit-multilayer matrix system(CMMS).This renders conventional models inadequate in accurately describing the flow field characteristics of *** this study,a semi-analytical model with second-order accuracy is developed to investigate the velocity profile characteristics of CMMS by coupling the Navier-Stokes(N–S)equations in the conduit and the Darcy-Brinkman(D-B)equation in the multilayer *** this model,the interface between the conduit and the matrix satisfies the velocity continuity and stress jumping *** contrast,different matrix interfaces require both velocity and stress to be *** model's validity is verified through Lattice Boltzmann Method(LBM)simulation,COMSOL simulation,and experimental data under different conduit apertures,matrix region numbers,and matrix permeability ***,the current model predicts discharges with higher accuracy than the Hagen-Poiseuille law and Darcy's law(the maximum error between the present model and the test is 7.24%).Furthermore,the existing Poiseuille's law,conduit-matrix model,and conduit-matrix1-matrix2 model are all special cases of the current semi-analytical model,thereby indicating its broader *** results reveal that the flow velocities in the surrounding matrix and the conduit regions also increase when the permeability of the matrix in proximity to the conduit ***,as the stress jumping coefficient at the interface approaches zero,the transition from free flow to seepage becomes smoother.

关键词： Flow field characteristics Velocity profile Conduit aperture Stress jumping Conduit-matrix system(CMS)

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Double-plume Lagrangian particle tracking model and its application in deep water oil spill

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Journal of Hydrodynamics 2023年第3期35卷 571-581页

作者： Xin-wei Ye Xiao-jing Niu Jian Jiang State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing100084China

Due to the density stratification of sea water,the dispersed oil droplets and gas bubbles with small diameters,as well as the dissolved components,may remain in some specific *** double-plume Lagrangian particle tracking model for bubbly plumes in vertical density stratified environments is improved and applied to predict the underwater pollutants in a *** model considers the different properties and dissolution processes of components in crude oil and focuses on their behavior and stratification differences in the *** crude oil components are divided into several groups and the dissolution of oil and gas is also *** model is applied to simulate the“Deepwater Horizon”oil spill accident in the Gulf of Mexico in *** results show several enrichment layers of oil and gas at different depth and the differences in concentration between components,which corresponds to the distribution of petroleum pollutants in the in-situ observation.

关键词： Oil spill double-plume model Lagrangian particle tracking the Gulf of Mexico

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Effect of temperature on surface fluid sediment properties with cyanobacterial bloom biomass accumulation

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Journal of Environmental Sciences 2025年第6期152卷 111-121页

作者： Chunliu Wang Da Xu Bosong Zhu Leilie Bai Lei Huang Helong Jiang School of the Environment and Safety Engineering Jiangsu UniversityZhenjiang 212013China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China College of Biology and the Environment Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of High Performance Civil Engineering Materials Jiangsu Sobute New Materials Co.Ltd.Nanjing 210008China State Key Laboratory of Hydroscience&Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China

In eutrophic shallow lakes,cyanobacterial blooms will occur frequently and then settle into sediment,leading the formation of fluid *** factors including temperature can influence surface sediment *** this study,the influence of temperatures on surface sediment properties was determined in microcosm experiments through monitoring sediment physicochemical and rheological *** one-month incubation,it was found that surface sediment density and water content varied exponentially with increase in temperatures from 10 to 35℃.The results of particle size distribution indicated that cyanobacterial blooms biomass(CBB)degradation in sediment led to sediment flocculation and *** themeantime,therewere high ratios polysaccharide/protein in extracellular polymeric substances(EPSs),which enhanced the sediment particle ***,the yield stress in rheological test for sediment with(R^(2)=0.97)and without(R^(2)=0.85)CBB presented an exponential decay with increase in *** a threshold value at 20℃ for sediment critical shear stress(τ_(cr))indicated that sediment could be resuspended easier when temperature was more than 20℃.Altogether,this study showed that the increase in temperatures with a threshold at 20℃,can cause sediment particle flocculation,resulting in a loose and fragile *** the results would be helpful to sediment management considering environmental effects of sediment suspension for eutrophication shallow lakes.

关键词： Cyanobacterial blooms Temperature Fluid sediment Physicochemical properties Yield shear stress

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Research on in situ stress inversion of deep-buried tunnel based on pressure/tension axis mechanism and geological structure

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Deep Underground Science and engineering 2023年第1期2卷 61-73页

作者： Guanfu Chen Xiaoli Liu Danqing Song State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijingChina

The investigation of the in situ stress distribution has always been a key condition for engineering design of deep tunnels and analysis of surrounding rock *** this paper,a comprehensive judgment method coupled with pressure/tension(P/T)axis mechanism and geological structure is proposed to invert the in situ stress in the Duoxiongla tunnel in *** the process of TBM tunnel excavation,3887 groups of microseismic events were collected by means of microseismic monitoring *** studying the temporal and spatial distribution of 3887 groups of microseismic events,42 groups of microseismic data were selected for in situ stress *** the focal mechanisms of 42 groups of microseisms were *** with the analysis of the previous geological survey,the inversion results of the in situ stress were *** to the focal mechanism of the tunnel area,the linear in situ stress inversion method was used to invert the in situ stress in the source ***,according to the PTGS(pressure/tension axis mechanism and geological structure)comprehensive judgment method proposed in this paper,the in situ stress of the tunnel microseismic region was *** results show that there are mainly three groups of fissures and joint surfaces in the tunnel area,and the in situ stress is dominated by the horizontrun tectonic stress;the main driving force of the rupture surface in the excavation process of Duoxiongla tunnel is the horizontal tectonic stress;the distribution of the maximum and minimum principal stress obtained by the inversion is consistent with the distribution of the P/T axis;combined with the linear in situ stress inversion method and the comprehensive judgment of PTGS,the azimuth and dip angles of the three principal stresses are finally determined as N90.71°E,4.06°,N5.35°W,3.06°,and N8.10W,85.32°,*** study verifies the feasibility of microseismic inversion of in situ stress.

关键词： deep tunnel focal mechanism geological structure microseismic monitoring stress inversion

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Three-dimensional hydro-mechanical coupling numerical simulation of shield-driven cross-river twin tunnels:A case study

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Underground Space 2024年第3期16卷 106-125页

作者： Chengwen Wang Xiaoli Liu Danqing Song Enzhi Wang Guohui Yan Ran Zhou Department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua UniversityBeijing 100084China YSD Rail Transit Construction Company Limited Guangzhou 510630China

With the rapid development of urban underground space,the construction of shield-driven cross-river twin tunnels is increasing,and the complex hydro-mechanical coupling effects and twin-tunnel interactions bring huge construction risks to such projects,which have attracted more and more *** study aims to understand the excavation effects induced by shield driving of cross-river twin tunnels through numerical simulation.A refined three-dimensional numerical model based on the fully coupled hydro-mechanical theory is *** model considers the main components of the slurry pressure balance shield(SPBS)machine,including support force,jacking thrust,grouting pressure,shield-rock interaction and lining-grouting interaction,as well as the detailed construction *** purpose is to examine the excavation effects during construction,including rock deformation around tunnels,the change in pore pressure,and the response of the *** results show the influence range of twin-tunnel excavation on rock deformation and pore pressure,as well as the modes of lining *** addition,this study also systematically investigates the effects of water level fluctuation and burial depth on twin-tunnel *** results indicate that the increase of water level or burial depth will enhance the excavation effects and strengthen the twin-tunnel *** results provide useful insights for estimating the construction impact range and degree of twin tunnels,and serve as basic references for the design of cross-river twin tunnels.

关键词： Numerical modeling Twin tunnels Crossing river Hydro-mechanical coupling Lining response

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Improving hydrodynamic modeling of river networks by incorporating data assimilation using a particle filter

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International Journal of Sediment Research 2023年第5期38卷 711-723页

作者： Chenhui Jiang Dejun Zhu Haobo Li Xiaoqun Liu Danxun Li State Key Laboratory of Hydroscience and Engineering Tsinghua University Hunan Institute of Water Resources and Hydropower Research

Numerical modeling is a well-recognized method for studying the hydrodynamic processes in river networks. Multi-source measurements also offer abundant information on the patterns and mechanisms within the processes. Therefore, improving hydrodynamic modeling of river networks through the use of data assimilation techniques has become a hot research topic in recent years. The particle filter(PF) is a commonly used data assimilation method and has been proven to be applicable to various nonlinear and non-Gaussian models. In the current study, an improved numerical hydrodynamic model for large-scale river networks is established by incorporating the advanced PF algorithm. Furthermore, the PF method based on the Gaussian likelihood function(GLF) and the method based on the Cauchy likelihood function(CLF) are compared for a complex river network scenario. The feasibility of the PF-based methods was evaluated through application to the Yangtze-Dongting River-lake Network(YDRN) by assimilating water stage data collected at six hydrometric stations during the entire hydrodynamic process in ***, the parameters used in the likelihood function, which affect the assimilation performance,also were explored in the current study. The study results found that the accuracy of the model-derived water stage data was improved when the PF-based methods are utilized, with improvement not only at the data assimilation(calibration) sites but also at three hydrometric stations not used in the data assimilation(i.e., verification sites). The highest average Nash-Sutcliffe Efficiency result for the six assimilation sites were 0.98 while the lowest summed root-mean-square-error result was 1.801 m. The comparison results also indicated that the CLF-based PF outperformed the GLF-based PF when highaccuracy observed data are available. Specifically, the CLF can effectively resolve the filtering failure problem and the dispersion problem of PFs, and further improve the accuracy of th

关键词： River networks Hydrodynamic process Particle filter Likelihood function

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Micro-destructive assessment of subgrade compaction quality using ultrasonic pulse velocity

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Journal of Rock Mechanics and Geotechnical engineering 2024年第11期16卷 4782-4797页

作者： Xuefei Wang Xuping Dong Xiangdong Li Jianmin Zhang Guowei Ma Jiale Li School of Civil and Transportation Engineering Hebei University of TechnologyTianjinChina Department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua UniversityBeijingChina

The ultrasonic pulse velocity(UPV)correlates significantly with the density and pore size of subgrade filling *** research conducts numerous Proctor and UPV tests to examine how moisture and rock content affect compaction *** study measures the changes in UPV across dry density and compaction *** compacted specimens exhibit distinct microstructures and mechanical properties along the dry and wet sides of the compaction curve,primarily influenced by internal water *** maximum dry density exhibits a positive correlation with the rock content,while the optimal moisture content demonstrates an inverse *** the rock content increases,the relative error of UPV measurement *** UPV follows a hump-shaped pattern with the initial moisture *** intelligent models are established to forecast dry *** measure of UPV and PSO-BP-NN model quickly assesses compaction quality.

关键词： Subgrade Compaction quality Ultrasonic pulse velocity(UPV) Intelligent model Proctor test Micro-destructive evaluation

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A review of rock macro-indentation:Theories,experiments,simulations,and applications

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2351-2374页

作者： Weiqiang Xie Xiaoli Liu Xiaoping Zhang Xinmei Yang Xiaoxiong Zhou State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China Yunlong Lake Laboratory of Deep Underground Science and Engineering Xuzhou221116China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

Rock macro-indentation plays a fundamental role in mechanical rock breaking for various rock engineering application,such as drilling,tunneling,cutting,and *** the past decades,extensive research has been conducted to understand the indentation mechanisms and responses through various *** review aims to provide an overview of the current status and recent advancements in theories,experiments,numerical simulations,and applications of macro-indentation in rock *** starts with elaborating on the mechanisms of macro-indentation,followed by a discussion of the merits and limitations of commonly used *** factors and their effects on indentation test results are then *** numerical simulation methods for rock macro-indentation are highlighted,along with their advantages and ***,the applications of indentation tests and indentation indices in characterizing rock properties are *** reveals that compression-tension,compression-shear,and composite models are widely employed in rock *** the compression-tension model is straightforward to use,it may overlook the anisotropic properties of *** the other hand,the composite model provides a more comprehensive description of rock indentation but requires complex ***,factors,such as indentation rate,indenter geometry,rock type,specimen size,and confining pressure,can significantly influence the indentation *** methods for macro-indentation encompass continuous medium,discontinuous medium,and continuous-discontinuous medium methods,with selection based on their differences in ***,rock macro-indentation can be practically applied to mining engineering,tunneling engineering,and petroleum drilling *** indices serve as valuable tools for characterizing rock strength,brittleness,and *** review sheds light on the development of rock macro-inde

关键词： Rock macro-indentation Indentation test Indentation indices Mechanism Rock breaking

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