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Dynamic properties of polyurethane foam adhesive-reinforced gravels

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Science China(Technological Sciences) 2021年第3期64卷 535-547页

作者： LIU Ping MENG MinQiang XIAO yang LIU hanlong yang Gui School of Civil Engineering Ludong UniversityYantai 264025China School of Civil Engineering Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China

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 ***,the dynamic properties of PFA-reinforced soils are not well *** 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 *** results showed that the shear modulus increased,and the damping ratio decreased as the PFA content,confining pressure and consolidation stress ratio *** 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 ***,the upper and lower bounds of the damping ratio were also proposed.

关键词： polyurethane foam adhesive gravel shear modulus damping ratio cyclic triaxial test

Modeling of strength and deformation of overconsolidated clays based on bounding surface plasticity

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Science China(Technological Sciences) 2016年第9期59卷 1452-1462页

作者： XIAO yang[[ LIU hanlong SUN YiFei LIU Hong State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing University College of Civil Engineering Chongqing University Faculty of Engineering and Information Sciences University of Wollongong

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.

关键词： overconsolidated clay overconsolidated ratio critical state theory yielding ratio peak state strength dilatancy

Modified Cam-Clay model incorporating unified nonlinear strength criterion

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Science China(Technological Sciences) 2011年第4期54卷 805-810页

作者： XIAO yang LIU hanlong LIANG Robert Y Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Nanjing 210098China 2 Geotechnical Research Institute Hohai UniversityNanjing 210098China Department of Civil Engineering University of AkronAkron 44325USA

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 *** covers wide ranges on the meridian and octahedral planes to describe nonlinear strength behaviors of *** 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 *** unified nonlinear strength criterion,demonstrated here,is capable of capturing the experimental results of different types of soils on the meridian and octahedral *** 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.

关键词： nonlinear strength criterion failure constitutive model complex stress condition

A constitutive model incorporating particle breakage for gravelly soil-structure interface under cyclic loading

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Science China(Technological Sciences) 2022年第12期65卷 2846-2855页

作者： CUI Hao XIAO yang SHU ShanZhi HE Xiang LIU hanlong School of Civil Engineering Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China Kiewit 10055 Trainstation CircleLone TreeCO 80124USA

Under cyclic loading,particle breakage occurs at gravelly soil-structure interface,resulting in the decrease of interface strength and the increase of normal *** 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 ***,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),*** 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 *** general,the simulation results are closer to the experimental results when particle breakage is considered.

关键词： gravelly soil-structure interface particle breakage cyclic loading constitutive model

New lightweight geomaterials:Biocemented sand mixed with expanded polystyrene beads

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Science China(Technological Sciences) 2017年第7期60卷 1118-1120页

作者： XIAO yang HE Xiang LIU hanlong State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing 400045China College of Civil Engineering Chongqing UniversityChongqing 400045China

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 insula... 详细信息

关键词： lightweight beads polystyrene expanded attractive instead recycling Portland insulation hydraulic

Modeling and behaviours of rockfill materials in three-dimensional stress space

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Science China(Technological Sciences) 2012年第10期55卷 2877-2892页

作者： XIAO yang LIU hanlong ZHU JunGao SHI WeiCheng Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China Geotechnical Research Institute Hohai UniversityNanjing 210098China School of Civil Engineering and Architecture Changzhou Institute of TechnologyChangzhou 213002China

A bounding surface model incorporating a unified nonlinear strength criterion is *** proposed bounding surface model contains 9 model parameters,which can be determined from the conventional triaxial *** bounding surface model can reproduce such behaviours as the strain hardening,the post-peak strain softening,and the volumetric strain contraction and *** 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 *** 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 *** 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.

关键词： bounding surface strength stress-strain three-dimensional stress constitutive model rockfill materials

Model predictions for behaviors of sand-nonplastic-fines mixtures using equivalent-skeleton void-ratio state index

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Science China(Technological Sciences) 2017年第6期60卷 878-892页

作者： XIAO yang SUN YiFei LIU hanlong XIANG Jia MA QiFeng LONG LeiHang Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing University Chongqing 400045 China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Chongqing 400030 China School of Civil Engineering Chongqing University Chongqing 400045 China Faculty of Engineering and Information Sciences University of Wollongong Wollongong 2522 Australia

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.

关键词： sand fines equivalent-skeleton void ratio critical-state strength dilatancy constitutive model

A 3D bounding surface model for rockfill materials

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Science China(Technological Sciences) 2011年第11期54卷 2904-2915页

作者： XIAO yang LIU hanlong ZHU JunGao SHI WeiCheng LIU MengCheng Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Nanjing 210098 China Geotechnical Research Institute Hohai University Nanjing 210098 China School of Civil Engineering and Architecture Changzhou Institute of Technology Changzhou 213002 China College of Architecture and Civil Engineering Zhejiang University of Technology Hangzhou 310014 China

A 3D bounding surface model is established for rockfill materials,which can be applied to appropriately predict the deformation and the stabilization of rockfill ***,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 ***,the constitutive equations of the 3D bounding surface model are established by several *** steps include the bounding surface incorporating the general nonlinear strength criterion,stress-dilatancy equations,the evolution of the bounding surface and the bounding surface ***,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 ***,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.

关键词： rockf'di material strength dilatancy 3D bounding surface constitutive model

Biomineralization and mineralization using microfluidics:A comparison study

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 661-669页

作者： yang Xiao Xiang He Guoliang Ma Chang Zhao Jian Chu hanlong Liu Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400045China School of Civil Engineering Chongqing UniversityChongqing400045China School of Civil and Environmental Engineering Nanyang Technological UniversitySingapore

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 *** minerals formed by biomineralization are generally the same as that by mineralization,their mechanical behaviors show a significant *** study aims to figure out the differences between biomineralization and mineralization processes by visualizing and tracking the formation of minerals using *** biomineralization and mineralization processes occurred in the Y-shaped sandcontaining microchip that mimics the underground sand *** from different areas in the reaction microchannel of microchips were captured to directly compare the distribution of *** size and numbers from different reaction times were measured to quantify the differences between biomineralization and mineralization processes in terms of crystal *** 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 *** addition,a more heterogeneous distribution of crystals was observed during the biomineralization *** precipitation behaviors were further explained by the classical nucleation crystal growth *** present microfluidic tests could advance the understanding of biomineralization and provide new insight into the optimization of biocementation technology.

关键词： Microbially induced carbonate precipitation (MICP) Biocementation Crystal Calcium carbonate Nucleation