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Rainfall-triggered waste dump instability analysis based on surface 3D deformation in physical model test

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Journal of Mountain Science 2024年第5期21卷 1549-1563页

作者： LI Hanlin JIN Xiaoguang HE Jie XUE Yunchuan YANG Zhongping school of civil engineering Chongqing UniversityChongqing 400038China

Landslide is the second largest natural disaster after earthquake. It is of significance to study the evolution laws and failure mechanism of landslides based on its surface 3D deformation information. Based on the rainfall-triggered waste dump instability model test, we studied the failure mechanisms of the waste dump by integrating surface deformation and internal slope stress and proposed novel parameters for identifying landslide stability. We developed a noncontact measurement device, which can obtain millimeter-level 3D deformation data for surface scene in physical model test;Then we developed the similar materials and established a test model for a waste dump. Based on the failure characteristics of slope surface, internal stress of slope body and displacement contours during the whole process, we divided the slope instability process in model test into four stages: rainfall infiltration and surface erosion, shallow sliding, deep sliding, and overall instability. Based on the obtained surface deformation data, we calculated the volume change during slope instability process and compared it with the point displacement on slope surface. The results showed that the volume change can not only reflect the slow-ultra acceleration process of slope failure, but also fully reflect the above four stages and reduce the fluctuations caused by random factors. Finally, this paper proposed two stability identification parameters: the volume change rate above the slip surface and the relative velocity of volume change rate. According to the calculation of these two parameters in model test, they can be used for study the deformation and failure mechanism of slope stability.

关键词： Waste dump stability Physical model test Surface 3D deformation Stability identification

Dynamic prediction of over-excavation gap due to posture adjustment of shield machine in soft soil

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Underground Space 2024年第3期16卷 44-58页

作者： Wenyu Yang Junjie Zheng Rongjun Zhang Sijie Liu Wengang Zhang school of civil and Hydraulic engineering Huazhong University of Science and TechnologyWuhan 430074China school of civil engineering Wuhan UniversityWuhan 430072China school of civil engineering Chongqing UniversityChongqing 400045China

The probability analysis of ground deformation is becoming a trend to estimate and control the risk brought by shield *** gap parameter is regarded as an effective tool to estimate the ground loss of tunnelling in soft *** specifically,x,which is a gap parameter component defined as the over(or insufficient)excavation due to the change in the posture of the shield machine,may contribute more to the uncertainty of the ground ***,the existing uncertainty characterization methods for x have several limitations and cannot explain the uncertain correlations between the relevant *** these lines,to better characterize the uncertainty of x,the multivariate probability distribution was developed in this work and a dynamic prediction was proposed for *** attain this goal,1523 rings of the field data coming from the shield tunnel between Longqing Road and Baiyun Road in Kunming Metro Line 5 were utilized and 44 parameters including the construction,stratigraphic,and posture parameters were collected to form the *** to the variance filter method,the mutual information method,and the value of the correlation coefficients,the original 44 parameters were reduced to 10 main parameters,which were unit weight,the stoke of the jacks(A,B,C,and D groups),the pressure of the pushing jacks(A,C groups),the chamber pressure,the rotation speed,and the total *** multivariate probability distribution was constructed based on the Johnson system of ***,the distribution was satisfactorily verified in explaining the pairwise correlation between x and other parameters through 2 million simulation *** last,the distribution was used as a prior distribution to update the marginal distribution of x with any group of the relevant parameters *** performance of the dynamic prediction was further validated by the field data of 3 shield tunnel cases.

关键词： Shield tunnel Ground loss Gap parameter Multivariate probability distribution Bayesian updating Dynamic prediction

Stability of bedded rock slopes subjected to hydro-fluctuation and associated strength deterioration

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 3233-3257页

作者： Bin Xu Xinrong Liu Yue Liang Xiaohan Zhou Zuliang Zhong school of River and Ocean engineering Chongqing Jiaotong UniversityChongqing400074China school of civil engineering Chongqing UniversityChongqing400045China

Reservoir-induced earthquakes(RIEs)occur frequently in the Three Gorges Reservoir Area(TGRA)and the rock mass strength of the hydro-fluctuation belt(HFB)deteriorates severely due to the reservoirinduced seismic *** models of typical bedded rock slopes(BRSs),***(GIS),moderately(MIS),and steeply(SIS)inclined slopes,were proposed according to field *** dynamic response mechanism and stability of the BRSs,affected by the rock mass deterioration of the HFB,were investigated by the shaking table test and the universal distinct element code(UDEC)***,the amplification coefficient of the peak ground acceleration(PGA)of the slope was gradually attenuated under multiple seismic loads,and the acceleration response showed obvious“surface effect”and“elevation effect”in the horizontal and vertical directions,***“S-type”cubic function and“steep-rise type”exponential function were used to characterize the cumulative damage evolution of the slope caused by microseismic waves(low seismic waves)and high seismic waves,*** to the dynamic responses of the acceleration,cumulative displacement,rock pressure,pore water pressure,damping ratio,natural frequency,stability coefficient,and sliding velocity of the slope,the typical evolution processes of the dynamic cumulative damage and instability failure of the slope were generalized,and the numerical and experimental results were *** the dynamic effects of the slope height(SH),slope angle(SA),bedding plane thickness(BPT),dip angle of the bedding plane(DABP),dynamic load amplitude(DLA),dynamic load frequency(DLF),height of water level of the hydro-fluctuation belt(HWLHFB),degradation range of the hydro-fluctuation belt(DRHFB),and degradation shape of the hydro-fluctuation belt(DSHFB),the sensitivity of factors influencing the slope dynamic stability using the orthogonal analysis method(OAM)was DLA>DRHFB>SA>SH>DLF>HWLHFB>DSHFB>DABP>BPT.

关键词： Bedded rock slopes Hydro-fluctuation belt Shaking table test UDEC simulation Dynamic response mechanism

Design and mechanical properties analysis of a cellular Waterbomb origami structure

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 193-202页

作者： Yongtao Bai Zhaoyu Wang Yu Shi school of civil engineering Chongqing UniversityChongqing 400045China Research Center of Steel Structure engineering Chongqing UniversityChongqing 400045China

Cellular structures are commonly used to design energy-absorbing structures,and origami structures are becominga prevalent method of cellular structure *** paper proposes a foldable cellular structure based on theWaterbomb origami *** geometrical configuration of this structure is ***-static compressiontests of the origami tube cell of this cellular structure are conducted,and load-displacement relationship curvesare *** simulations are carried out to analyze the effects of aspect ratio,folding angle,thicknessand number of layers of origami tubes on initial peak force and specific energy absorption(SEA).Calculationformulas for initial peak force and SEA are obtained by the multiple linear regression *** degree ofinfluence of each parameter on the mechanical properties of the single-layer tube cell is *** resultsshow that the cellular structure exhibits negative stiffness and periodic load-bearing capacity,as well as foldingangle has the most significant effect on the load-bearing and energy-absorbing *** adjusting the designparameters,the stiffness,load-bearing capacity and energy absorption capacity of this cellular structure can beadjusted,which shows the programmable mechanical properties of this cellular *** foldability andthe smooth periodic load-bearing capacity give the structure potential for application as an energy-absorbing structure.

关键词： Cellular structure Waterbomb origami Mechanical metamaterial Numerical simulation Energy absorption

Model-based investigation on building thermal mass utilization and flexibility enhancement of air conditioning loads

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Building Simulation 2024年第8期17卷 1289-1308页

作者： Yue Sun Tianyi Zhao Shan Lyu Institute of Building Energy School of Infrastructure EngineeringDalian University of TechnologyDalian116024China school of civil engineering Chongqing UniversityChongqing 400045China

Building air conditioning systems(ACs)can contribute to the stable operation of power grids by participating in peak load shaving programs,but the participants need a fast and accurate zone temperature prediction model,e.g.,the detailed room thermal-resistance(RC)model,to improve peak shaving effect and avoid obvious thermal ***,when applying the detailed room RC model to multi-zone buildings,conventional studies mostly consider the heat transfer among neighboring rooms,which contributes little to the prediction accuracy improvement,but leads to complicated model structure and heavy ***,a distributed RC model is developed for multi-zone buildings in this *** to conventional models,the proposed model considers the total heat transfer between the building and the air,and ignores the heat transfer among indoor air in neighboring rooms through internal walls with heavy thermal mass,thereby having comparable temperature prediction accuracy,simpler structure,and stronger *** on the model,the effectiveness of passive pre-cooling strategies in reducing the air conditioning loads during peak periods is *** indicate that the thermal insulation performance of opaque building envelope is quite important to the flexibility enhancement of air conditioning *** an uninsulated building envelope,passive pre-cooling is useless for the peak load *** comparison,well insulated opaque building envelope enables the building thermal mass to be utilized through passive pre-cooling,which leads to the air conditioning loads during peak periods being further reduced by about 12%.

关键词： RC model passive pre-cooling internal thermal mass building energy flexibility

Exploring the Applications of Digital Twin Technology in Enhancing Sustainability in civil engineering:A Review

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Structural Durability & Health Monitoring 2024年第5期18卷 577-598页

作者： Jiamin Huang Ping Wu Wangxin Li Jun Zhang Yidong Xu school of civil engineering Chongqing Jiaotong UniversityChongqing400074China school of civil engineering and Architecture NingboTech UniversityNingbo315100China school of civil engineering Lanzhou University of TechnologyLanzhou730050China

With the advent of the big data era and the rise of Industrial Revolution 4.0,digital twins(DTs)have gained sig-niﬁcant attention in various *** offer the opportunity to combine the physical and digital worlds and aid the digital transformation of the civil engineering *** this paper,605 documents obtained from the search wereﬁrst analysed using CiteSpace for literature visualisation,and an author co-occurrence network,a keyword co-occurrence network,and a keyword clustering set were ***,through a literature review of 86 papers,this paper summarises the current status of DT application in civil engineering based on a review of the origins,concepts,and implementation techniques of DTs,and it introduces the application of DTs in the full project *** study shows that DTs have great potential to address many of the challenges faced by civil *** this regard,the paper also presents some thoughts on the future directions of DT research.

关键词： Digital twins civil engineering full lifecycle literature visualisation analysis

Preparation and Reinforcement Adaptability of Jute Fiber Reinforced Magnesium Phosphate Cement Based Composite Materials

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Journal of Wuhan university of Technology(Materials Science) 2024年第4期39卷 999-1009页

作者：刘芯州郭远臣 WANG Rui XIANG Kai WANG Xue YE Qing College of civil engineering Chongqing Three Gorges UniversityChongqing 404100China

To improve the brittleness characteristics of magnesium phosphate cement-based materials(MPC)and to promote its promotion and application in the field of structural reinforcement and repair,this study aimed to increase the toughness of MPC by adding jute fiber,explore the effects of different amounts of jute fiber on the working and mechanical properties of MPC,and prepare jute fiber reinforced magnesium phosphate cement-based materials(JFRMPC)to reinforce damaged *** improvement effect of beam performance before and after reinforcement was compared,and the strengthening and toughening mechanisms of jute fiber on MPC were explored through microscopic *** experimental results show that,as the content of jute fiber(JF)increases,the fluidity and setting time of MPC decrease continuously;When the content of jute fiber is 0.8%,the compressive strength,flexural strength,and bonding strength of MPC at 28 days reach their maximum values,which are increased by 18.0%,20.5%,and 22.6%compared to those of M0,*** beam strengthened with JFRMPC can withstand greater deformation,with a deflection of 2.3 times that of the unreinforced beam at *** strain of the steel bar is greatly reduced,and the initial crack and failure loads of the reinforced beam are increased by 192.1%and 16.1%,respectively,compared to those of the unreinforced *** JF added to the MPC matrix dissipates energy through tensile fracture and debonding pull-out,slowing down stress concentration and inhibiting the free development of cracks in the matrix,enabling JFRMPC to exhibit higher strength and better *** JF does not cause the hydration of MPC to generate new compounds but reduces the amount of hydration products generated.

关键词： magnesium phosphate cement jute fiber reinforcement of damaged beam flexural behavior

Vibration attenuation performance of wind turbine tower using a prestressed tuned mass damper under seismic excitation

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Earthquake engineering and engineering Vibration 2024年第2期23卷 511-524页

作者： Lei Zhenbo Liu Gang Wang Hui Hui Yi school of civil engineering Chongqing UniversityChongqing 400045China Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityMinistry of EducationChongqing 400045China

With the rapid development of large megawatt wind turbines,the operation environment of wind turbine towers(WTTs)has become increasingly *** particular,seismic excitation can create a resonance response and cause excessive vibration of the *** investigate the vibration attenuation performance of the WTT under seismic excitations,a novel passive vibration control device,called a prestressed tuned mass damper(PS-TMD),is presented in this ***,a mathematical model is established based on structural dynamics under seismic ***,the mathematical analytical expression of the dynamic coefficient is deduced,and the parameter design method is obtained by system tuning ***,based on a theoretical analysis and parameter design,the numerical results showed that the PS-TMD was able to effectively mitigate the resonance under the harmonic basal ***,the time-history analysis method is used to verify the effectiveness of the traditional pendulum tuned mass damper(PTMD)and the novel PS-TMD device,and the results indicate that the vibration attenuation performance of the PS-TMD is better than the *** addition,the PS-TMD avoids the nonlinear effect due to the large oscillation angle,and has the potential to dissipate hysteretic energy under seismic excitation.

关键词： wind turbine tower prestressed tuned mass damper vibration control seismic excitation numerical simulation

Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model

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Computer Modeling in engineering & Sciences 2024年第3期138卷 2305-2338页

作者： Chenxi Xiu Xihua Chu school of civil engineering Chongqing Jiaotong UniversityChongqing400074China school of civil engineering Wuhan UniversityWuhan430072China

This paper presents a micromechanics-based Cosserat continuum model for microstructured granular *** utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural *** microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized ***,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield *** investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)*** demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain *** study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials ***,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic *** parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element.

关键词： Granular materials micromechanics Cosserat elastoplastic model microstructures failure behaviors