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19篇 您的检索式:作者名="Yang Hanlong"
    题名 作者 年代 出处 被引量
1A 3D bounding surface model for rockfill materials显示文摘A 3D bounding surface model is established for rockfill materials,which can be applied to appropriately predict the deformation and the stabilization of rockfill dams.Firstly,an associated plastic flow rule for rockfill materials is investigated based on the elaborate data from the large-style triaxial compression tests and the true triaxial tests.Secondly,the constitutive equations of the 3D bounding surface model are established by several steps.These steps include the bounding surface incorporating the general nonlinear strength criterion,stress-dilatancy equations,the evolution of the bounding surface and the bounding surface plasticity.Finally,the 3D bounding surface model is used to predict the mechanical behaviors of rockfill materials from the large-style triaxial compression tests and the true triaxial tests.Consequently,the proposed 3D bounding surface model can well capture such behaviors of rockfill materials as the strain hardening,the post-peak strain softening,and the volumetric strain contraction and expansion in both two-and three-dimensional stress spaces.XIAO Yang LIU HanLong ZHU JunGao SHI WeiCheng LIU MengCheng 2011Science China(Technological Sciences)2011,54,11:16
2A new elliptic-parabolic yield surface model revised by an adaptive criterion for granular soils显示文摘An adaptive criterion for shear yielding as well as shear failure of soils is proposed in this paper to address the fact that most criteria,including the Mohr-Coulomb criterion,the Lade criterion and the Matsuoka-Nakai criterion,cannot agree well with the experimental results when the value of the intermediate principal stress parameter is too big.The new criterion can adjust an adaptive parameter based on the experimental results in order to make the theoretical calculations fit the test results more accurately.The original elliptic-parabolic yield surface model can capture both soil contraction and dilation behaviors.However,it normally over-predicts the soil strength due to its application of the Extended Mises criterion.A new elliptic-parabolic yield surface mode is presented in this paper,which introduces the adaptive criterion in three-dimensional principal stress space.The new model can well model the stress-strain behavior of soils under general stress conditions.Compared to the original model which can only simulate soil behavior under triaxial compression conditions,the new model can simulate soil behaviors under both triaxial compression conditions and general stress conditions.LIU HanLong 1,2 ,XIAO Yang 1,2 ,LIU JinYuan 3 &LI GuoYing 4 1 Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University, Nanjing 210098,China 2 Geotechnical Research Institute,Hohai University,Nanjing 210098,China 3Department of Civil Engineering,Ryerson University,Toronto,Canada 4 Department of Geotechnical Engineering,Nanjing Hydraulic Research Institute,Nanjing 210014,China 2010Science China(Technological Sciences)2010,53,8:12
3Modeling and behaviours of rockfill materials in three-dimensional stress space显示文摘A bounding surface model incorporating a unified nonlinear strength criterion is proposed.The proposed bounding surface model contains 9 model parameters,which can be determined from the conventional triaxial tests.The bounding surface model can reproduce such behaviours as the strain hardening,the post-peak strain softening,and the volumetric strain contraction and expansion.Based on the comparisons between the predictions and the test results,the proposed strength criterion and model can well reproduce the experimental results of the strength and stress-strain behaviours of rockfill material in three-dimensional stress space.The strength behaviour of rockfill material is summarized as:(a) the failure stress ratio decreases with the initial confining pressure on the meridian plane;(b) the failure deviatoric stress decreases with the Lode angle from 0o to 60o on the deviatoric plane.The stress ratio decreases with increasing one of such factors as the initial void ratio,the intermediate principal stress ratio and the minor principal stress at the same strain when the other factors are given.XIAO Yang LIU HanLong ZHU JunGao SHI WeiCheng 2012Science China(Technological Sciences)2012,55,10:10
4Dilatancy equation of rockfill material under the true triaxial stress condition显示文摘Rockfill material is widely used for construction of high rockfill dam due to its facility,economical cost,high strength and effective aseismatic property.It is provoked profoundly to propose a suitable constitutive model for a better application of this material.The dilatancy equation of rockfill material plays a significant role in the constitutive model.For the sake of simplicity,a dilatancy equation is established by the linear least square method on the basis of the rearranged data of rockfill material in the true triaxial tests.Based on the fact that the rearranged data at different initial confining pressures are aligned in a narrow band,the dilatancy behavior of rockfill material is independent of the initial confining pressure.However,different from the initial confining pressure,both the intermediate principal stress ratio and the specimen density exhibit a remarkable influence on the dilatancy behaviors of rockfill material.Furthermore,the predictions of the proposed dilatancy equation are in a good agreement with the rearranged test data of rockfill material at different specimen densities and stress paths.XIAO Yang 1,2,LIU HanLong 1,2,ZHU JunGao 1,2 & SHI WeiCheng 1,3 1 Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,China 2 Geotechnical Research Institute,Hohai University,Nanjing 210098,China 3 School of Civil Engineering and Architecture,Changzhou Institute of Technology,Changzhou 213002,China 2011Science China(Technological Sciences)2011,54,S1:9
5Shear behavior of coarse aggregates for dam construction under varied stress paths显示文摘Coarse aggregates are the major infrastructure materials of concrete-faced rock-fill dams and are consolidated to bear upper and lateral loads. With the increase of dam height, high confining pressure and complex stress states complicate the shear behavior of coarse aggregates, and thus impede the high dam's proper construction, operation and maintenance. An experimental program was conducted to study the shear behavior of dam coarse aggregates using a large-scale triaxial shear apparatus. Through triaxial shear tests, the strain-stress behaviors of aggregates were observed under constant confining pressures: 300 kPa, 600 kPa, 900 kPa and 1200 kPa. Shear strengths and aggregate breakage characteristics associated with high pressure shear processes are discussed. Stress path tests were conducted to observe and analyze coarse aggregate response under complex stress states. In triaxial shear tests, it was found that peak deviator stresses increase along with confining pressures, whereas the peak principal stress ratios decrease as confining pressures increase. With increasing confining pressures, the dilation decreases and the contraction eventually prevails. Initial strength parameters (Poisson’s ratio and tangent modulus) show a nonlinear relationship with confining pressures when the pressures are relatively low. Shear strength parameters decrease with increasing confining pressures. The failure envelope lines are convex curves, with clear curvature under low confining pressures. Under moderate confining pressures, dilation is offset by particle breakage. Under high confining pressures, dilation disappears.Liu Hanlong Deng An Shen Yang 2008Water Science and Engineering2008,1,1:9
6Model predictions for behaviors of sand-nonplastic-fines mixtures using equivalent-skeleton void-ratio state index显示文摘It is a challenge to suggest a constitutive model for describing the stress-strain behavior of sand-fines mixtures due to that these granular mixtures exhibited very complex behaviors at different densities, pressures and fines contents. In this study, an elastoplastic constitutive model within the framework of the bounding surface plasticity and critical state theories was proposed for sand-nonplastic-fines mixtures by using the concept of the equivalent-skeleton void ratio and equivalent-skeleton void-ratio state index. The proposed model with a set of material constants calibrated from a few tests could be used to model the fines-dependent and state-dependent behaviors of the sand-nonplastic-fines mixture including the strain- softening and volumetric-expansion behaviors in the drained triaxial compression tests, and also the effects of fines content on the critical state lines in both the deviatoric stress versus mean effective stress and the void ratio versus mean effective stress planes.XIAO Yang SUN YiFei LIU HanLong XIANG Jia MA QiFeng LONG LeiHang 2017Science China(Technological Sciences)2017,60,6:7
7Modified Cam-Clay model incorporating unified nonlinear strength criterion显示文摘A unified nonlinear strength criterion(i.e UNS criterion) is proposed,for the sake of versatility,to capture the complex strength behaviors of frictional materials in geotechnical field.It covers wide ranges on the meridian and octahedral planes to describe nonlinear strength behaviors of soils.The Modified Cam-Clay model,incorporating the unified nonlinear strength criterion,is employed as an example to derive working mathematical equations and to illustrate yielding surfaces in three-dimensional stress space for improving the model's predictive capability.The unified nonlinear strength criterion,demonstrated here,is capable of capturing the experimental results of different types of soils on the meridian and octahedral planes.In addition,the revised model,based on this unified nonlinear strength criterion,though very simple,is versatile to predict the true triaxial test results from literature when considering the influences of the intermediate principal stress on strength and deformation under complex stress conditions.XIAO Yang LIU HanLong LIANG Robert Y 2011Science China(Technological Sciences)2011,54,4:6
8A constitutive model for the state-dependent behaviors of rockfill material considering particle breakage显示文摘The particle breakage during specimen compaction had more significant influence on the position of the breakage critical-state line(BCSL)of Tacheng rockfill material(TRM)in the e-lnp’plane than the particle breakage during shearing,based on the large-scale triaxial compression tests on TRM in a wide range of densities and pressures.The state-dependent dilatancy and the plastic modulus were correlated to the breakage index,based on the formulations of the BCSL of TRM in the e-lnp’plane.The state-dependent model considering particle breakage was proposed for TRM within the framework of the generalized plasticity theory.The proposed model contained fourteen material constants.The test data of TRM from Group A were adopted to determine these material constants,while the test data from Group B were used independently to validate the model predictive capacity.The comparisons between model simulations and test data illustrated that the model with consideration of particle breakage could well represent the stress-strain behaviors of TRM,e.g.,the strain hardening and volumetric contraction behaviors at a loose state and the strain softening and volumetric expansion behaviors at a dense state,and also the particle breakage behaviors of TRM.XIAO Yang LIU HanLong YANG Gui CHEN YuMin JIANG JingShan 2014Science China(Technological Sciences)2014,57,8:6
9New lightweight geomaterials:Biocemented sand mixed with expanded polystyrene beads显示文摘Lightweight geomaterial(LWGM)possesses such merit characteristics as low unit weight,environmental protection(recycling these materials instead of stockpiling them),buffering mechanical property and thermal insulation[1].LWGM,an attractive substitute for earth fills,can be applied inXIAO Yang HE Xiang LIU HanLong 2017Science China(Technological Sciences)2017,60,7:4
10Dynamic properties of polyurethane foam adhesive-reinforced gravels显示文摘Polyurethane foam adhesive(PFA)has been introduced as an alternative stabilizer in geotechnical applications because PFA can improve the engineering characteristics of soil by filling the pore space and generating adhesive bonding among the particles.However,the dynamic properties of PFA-reinforced soils are not well understood.To analyze the dynamic characteristics of PFA-reinforced gravels,a series of cyclic triaxial tests were carried out to investigate the shear modulus and damping ratio of PFA-reinforced gravels,and to determine the corresponding effects of the PFA content,confining pressure,consolidation stress ratio and loading frequency.The results showed that the shear modulus increased,and the damping ratio decreased as the PFA content,confining pressure and consolidation stress ratio increased.In contrast,the effect of the loading frequency,which ranged from 0.05 to 1 Hz,was negligible.A modified hyperbolic empirical model can consider the effect of the PFA content on the maximum shear modulus and predict the relationship between the normalized shear modulus and the normalized shear strain was proposed.Moreover,the upper and lower bounds of the damping ratio were also proposed.LIU Ping MENG MinQiang XIAO Yang LIU HanLong YANG Gui 2021Science China(Technological Sciences)2021,64,3:3
11Testing and modeling of rockfill materials:A review显示文摘The research development of rockfill materials(RFM) was investigated by a series of large-scale triaxial tests.It is observed that confining pressure and particle breakage play important roles in the mechanical property,dilatancy relation and constitutive model of RFM.In addition,it is observed that the conventional dilatancy relation and constitutive model are not suitable for RFM due to the complex mechanical behavior.Hence,it needs to propose a unified constitutive model of RFM,considering the statedependent and particle breakage behavior.Yang Xiao Hong Liu Wengang Zhang Hanlong Liu Feng Yin Youyu Wang 2016Journal of Rock Mechanics and Geotechnical Engineering2016,8,3:2
12Strength-increase mechanism and microstructural characteristics of a biotreated geomaterial显示文摘Microbially induced calcite precipitation(MICP)is a recently proposed method that is environmentally friendly and has considerable potential applications in artificial biotreated geomaterials.New artificial biotreated geomaterials are produced based on the MICP technology for different parent soils.The purpose of this study is to explore the strength-increase mechanism and microstmctural characteristics of the biotreated geomaterial through a series of experiments.The results show that longer mineralization time results in higher-strength biotreated geomaterial.The strength growth rate rapidly increases in the beginning and remains stable afterwards.The calcium ion content significantly increases with the extended mineralization time.When standard sand was used as a parent soil,the calcium ion content increased to a factor of 39 after 7 days.The bacterial cells with attached calcium ions serve as the nucleus of crystallization and fill the pore space.When fine sand was used as a parent soil,the calcium ion content increased to only a factor of 7 after 7 days of mineralization.The nucleus of crystallization could not normally grow because of the limited pore space.The porosity and variation in porosity are clearly affected by the parent soil.Therefore,the strength of the biotreated geomaterial is affected by the parent soil properties,mineralization time,and granular material pore space.This paper provides a basis for theory and experiments for biotreated geomaterials in future engineering practice.Chi LI Siriguleng BAI Tuanjie ZHOU Hanlong LIU Xiao QIN Shihui LIU Xiaoying LIU Yang XIAO 2020Frontiers of Structural and Civil Engineering2020,14,3:2
13A creatinine-based model for predicting recurrent bleeding after modified percutaneous transhepatic variceal embolization in patients with cirrhosis显示文摘Background:Patients who survive initial esophagogastric variceal bleeding(EVB)are at an increased risk of recurrent bleeding and death;however,a reliable predictive model is lacking.We aimed to develop a model for rebleeding prediction in patients with EVB after modified percutaneous transhepatic variceal embolization(PTVE)with cyanoacrylate.Methods:A total of 122 patients with EVB who underwent PTVE from January 2015 to November 2020 were enrolled.Multivariate logistic analyses were conducted to determine independent risk factors for nomogram construction.The discrimination,calibration,and clinical utility of the nomogram were compared with the Model for End-stage Liver Disease score(MELD)and the Child–Pugh model.Risk stratification was performed according to the nomogram.Results:Rebleeding within 3 months of PTVE occurred in 32 patients(26.2%).Independent rebleeding indicators included prior history of endoscopic therapy,Child–Pugh score,partial splenic embolization,and creatinine level.The nomogram incorporating these four predictors achieved excellent calibration and discriminatory abilities,with a concordance index of 0.85,which was confirmed to be 0.83 through bootstrapping validation.The nomogram demonstrated superior discrimination and clinical applicability than the MELD and Child–Pugh models.As shown in the Kaplan–Meier curves,high-risk patients had a high probability of rebleeding(P<0.001).Conclusions:The creatinine-based nomogram had a superior ability to predict rebleeding after PTVE in patients with EVB.Risk stratification may help identify high-risk patients and lead to the earlier implementation of aggressive treatments and formulation of intensive follow-up plans.Kun Ji Xin Li Hanlong Zhu Si Zhao Pengchao Zhan Yang Shi Shuwen Ye Bingcan Xie Yuyuan Zhang Peng Yu Zhigang Ren Juan Ding Xinwei Han Zhen Li 2022Journal of Interventional Medicine2022,5,2:1
14Robust observation and fault diagnosis in aclass of time-delay control systems 显示文摘Yang Hanlong Saif Mehrdad 1997IEEE Pro American Control Conf1997,,1:1
15Modeling of strength and deformation of overconsolidated clays based on bounding surface plasticity显示文摘An elastoplastic constitutive model for overconsolidated clays is established in the framework of the critical state theory and bounding surface plasticity theory. The bounding surface is defined as the maximum yield surface in the loading history. A yielding ratio, i.e., an internal variant, is defined as the size ratio of the current yield surface to the corresponding bounding surface. The yielding ratio instead of the overconsolidation ratio(OCR) is used to evaluate the strength and stress-strain behaviors of overconsolidated clays in the shearing process. The bounding stress ratio incorporating the effect of the yielding ratio is used to characterize the potential failure strength of the overconsolidated clays. The dilation stress ratio taking into account the effect of the yielding ratio is applied to describe the dilatancy behaviors of the overconsolidated clays. Comparisons between model predictions and test data show that the proposed model could well capture the strength and stress-strain behaviors of normally consolidated and overconsolidated clays.XIAO Yang LIU HanLong SUN YiFei LIU Hong 2016Science China(Technological Sciences)2016,59,9:1
16Grain crushing in geoscience materials-Key issues on crushing response,measurement and modeling:Review and preface显示文摘Grain crushing is commonly encountered in deep foundation engineering,high rockfill dam engineering,railway engineering,mining engineering,coastal engineering,petroleum engineering,and other geoscience application.Grain crushing is affected by fundamental soil characteristics,such as their mineral strength,grain size and distribution,grain shape,density and specimen size,and also by external factors including stress magnitude and path,loading rate and duration,degree of saturation,temperature and geochemical environment.Crushable material becomes a series of different materials with the change in its grading during grain crushing,resulting in a decrease in strength and dilatancy and an increase in compressibility.Effects of grain crushing on strength,dilatancy,deformation and failure mechanisms have been extensively investigated through laboratory testing,discrete element method(DEM)modelling,Weibull statistics,and constitutive modelling within the framework of the extended crushing-dependent critical state theory or the energy-based theory.Eleven papers summarized in this review article for this special issue addressed the above issues in grain crushing through the advanced testing and modelling.Yang Xiao Chandrakant SDesai Ali Daouadji Armin WStuedlein Hanlong Liu Hossam Abuel-Naga 2020Geoscience Frontiers2020,11,2:1
17A constitutive model incorporating particle breakage for gravelly soil-structure interface under cyclic loading显示文摘Under cyclic loading,particle breakage occurs at gravelly soil-structure interface,resulting in the decrease of interface strength and the increase of normal displacement.Based on the theory of critical state soil mechanics,the modified Cam-Clay model(MCC)was extended to the plane strain condition of the interface,the state parameter was introduced and the influence of particle breakage on the critical state line was considered,and the cyclic constitutive model for gravelly soil-structure interface considering particle breakage was established by using the non-associated flow rule.Then,the established cyclic constitutive model was used to simulate large-scale cycle direct shear tests of Zipingpu rockfill-steel interface and Zipingpu rockfill-concrete interface under constant normal load(CNL)and constant normal stiffness(CNS),respectively.The simulation results show that under the CNL cyclic loading path,there is little difference between the cyclic shear stress considering particle breakage and that without particle breakage,but the normal displacement considering particle breakage is larger than that without particle breakage,and the difference increases with the increasing number of cycles and normal stress;Under the CNS cyclic loading path,with the increase of the number of cycles,the cyclic shear stress and cyclic normal stress considering particle breakage is significantly smaller than that without particle breakage,and the shear contraction of normal displacement becomes more obvious.In general,the simulation results are closer to the experimental results when particle breakage is considered.CUI Hao XIAO Yang SHU ShanZhi HE Xiang LIU HanLong 2022Science China(Technological Sciences)2022,65,12:0
18ToMFIR-based fault detection approach in frequency domain显示文摘This paper is to explore further results for total measurable fault information-based residual(ToMFIR) approach to fault detection in dynamic systems.The ToMFIR contains the essential fault information and remains unaffected by control actions in a closed-loop system.It is composed of controller residual and output residual and some of further results are developed in frequency domain.Besides the ability of detecting actuator and sensor faults,it is able to detect faults/failures resulting from the computer used for control purpose that generates control signals.Currently,all of existing fault detection schemes cannot achieve the same task at all.A practical DC motor example,with a PID controller,is used to demonstrate the effectiveness of the ToMFIR-based fault detection.A comparison with the standard observer-based technique is also provided.Wen Chen Chih Ping Yeh Hanlong Yang 2011Journal of Systems Engineering and Electronics2011,22,1:0
19Biomineralization and mineralization using microfluidics:A comparison study显示文摘Biomineralization through microbial process has attracted great attention in the field of geotechnical engineering due to its ability to bind granular materials,clog pores,and seal fractures.Although minerals formed by biomineralization are generally the same as that by mineralization,their mechanical behaviors show a significant discrepancy.This study aims to figure out the differences between biomineralization and mineralization processes by visualizing and tracking the formation of minerals using microfluidics.Both biomineralization and mineralization processes occurred in the Y-shaped sandcontaining microchip that mimics the underground sand layers.Images from different areas in the reaction microchannel of microchips were captured to directly compare the distribution of minerals.Crystal size and numbers from different reaction times were measured to quantify the differences between biomineralization and mineralization processes in terms of crystal kinetics.Results showed that the crystals were precipitated in a faster and more uncontrollable manner in the mineralization process than that in the biomineralization process,given that those two processes presented similar precipitation stages.In addition,a more heterogeneous distribution of crystals was observed during the biomineralization process.The precipitation behaviors were further explained by the classical nucleation crystal growth theory.The present microfluidic tests could advance the understanding of biomineralization and provide new insight into the optimization of biocementation technology.Yang Xiao Xiang He Guoliang Ma Chang Zhao Jian Chu Hanlong Liu 2024Journal of Rock Mechanics and Geotechnical Engineering2024,16,2:0
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