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International Journal of Mining Science and Technology 2024年第2期34卷 149-165页

作者： Xiaoping Zhou Linyuan Han Jing Bi Yundong Shou school of civil engineering Wuhan UniversityWuhan 430072China College of civil engineering Guizhou UniversityGuiyang 550025China

High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data.

关键词： Dynamic behaviors True triaxial compression High strain rates Dynamic failure mechanism PFC3D-FLAC3D coupled method

Dynamic Response Impact of Vehicle Braking on Simply Supported Beam Bridges with Corrugated Steel Webs Based on Vehicle-Bridge Coupled Vibration Analysis

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Computer Modeling in engineering & Sciences 2024年第6期139卷 3467-3493页

作者： Yan Wang Siwen Li Na Wei school of civil engineering Zhengzhou UniversityZhengzhou450001China

A novel approach for analyzing coupled vibrations between vehicles and bridges is presented,taking into account spatiotemporal effects and mechanical phenomena resulting fromvehicle braking.Efficient modeling and solution of bridge vibrations induced by vehicle deceleration are realized using this method.The method’s validity and reliability are substantiated through numerical examples.A simply supported beam bridge with a corrugated steel web is taken as an example and the effects of parameters such as the initial vehicle speed,braking acceleration,braking location,and road surface roughness on the mid-span displacement and impact factor of the bridge are analyzed.The results show that vehicle braking significantly amplifies mid-span displacement and impact factor responses in comparison to uniform vehicular motion across the bridge.Notably,the influence of wheelto-bridge friction forces is of particular significance and cannot be overlooked.When the vehicle initiates braking near the middle of the span,both the mid-span displacement and impact factor of the bridge exhibit substantial increases,further escalating with higher braking acceleration.Under favorable road surface conditions,the midspan displacement and the impact factor during vehicle braking may exceed the design values stipulated by codes.It is important to note that road surface roughness exerts a more pronounced effect on the impact factor of the bridge in comparison to the effects of vehicle braking.

关键词： Corrugated steel web girder bridges simply supported beam bridges vehicle-bridge coupled vibration braking impact factor

Effect of Size Change on Mechanical Properties of Monolayer Arsenene

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 206-212页

作者：郭娟刘贵立孙震宇 school of Architecture and civil engineering Shenyang University of TechnologyShenyang 110870China

The Young's modulus, shear modulus and Poisson's ratio of monolayer arsenene with different sizes were calculated by finite element method, so as to explore the influence of dimension and orientation on the mechanical properties of monolayer arsenene. The calculation results show that the small size has a significant effect on the mechanical properties of the monolayer arsenene. The smaller the size, the larger the Young's modulus and Poisson's ratio of the monolayer arsenene. The size change has a great influence on the Young's modulus of the arsenene handrail direction, and the Young's modulus of the zigzag direction is not sensitive to the size change. Similarly, the size change has a significant effect on the shear modulus of arsenene in the handrail direction, while the shear modulus in the zigzag direction has no significant effect on its size change. For the Poisson's ratio, the situation is just the opposite, and the effect of the size change on the Poisson's ratio of the arsenene zigzag direction is greater than that of the handrail direction.

关键词： finite element method arsenene size change mechanical properties

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

An extended numerical model of the first exothermic peak for three dimensional printed cement-based materials

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Frontiers of Structural and civil engineering 2024年第1期18卷 80-88页

作者： Wei JIANG Wenqian LI Xi CHEN school of Materials Science and engineering Tongji UniversityShanghai 200092China school of civil engineering Tongji UniversityShanghai 200092China

The first exothermic peak of cement-based material occurs a few minutes after mixing,and the properties of three dimensional(3D)printed concrete,such as setting time,are very sensitive to this.Against this background,based on the classical Park cement exothermic model of hydration,we propose and construct a numerical model of the first exothermic peak,taking into account the proportions of C_(3)S,C_(3)A and quicklime in particular.The calculated parameters are calibrated by means of relevant published exothermic test data.It is found that this developed model offers a good simulation of the first exothermic peak of hydration for C_(3)S and C_(3)A proportions from 0 to 100% of cement clinker and reflects the effect of quicklime content at 8%-10%.The unique value of this research is provision of an important computational tool for applications that are sensitive to the first exothermic peak of hydration,such as 3D printing.

关键词： 3D printed cement-based materials cement hydration the first exothermic peak liquid quick-setting agent numerical model

The Role of the Spatial Network in Urban Disaster Risk Variations:Reimagining the Notion of Spatial Vulnerability at the Urban Scale

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International Journal of Disaster Risk Science 2024年第3期15卷 303-316页

作者： Monia Del Pinto Ksenia Chmutina Falli Palaiologou Lee Bosher school of Architecture Building and Civil Engineering Loughborough University school of Business University of Leicester

The notion of “spatial vulnerability” is present in most disaster studies with a strong geographical connotation and accordingly is adopted at all scales, including the urban. While enabling mapping and visualizing risk patterns at macroscales, this geocentric foundation fails to capture disaster risk dynamics associated with the urban spatial network—an element that plays a significant role in the everyday and emergency functioning of cities, enabling users' movement and interaction. Yet,urban vulnerability assessment overlooks this aspect and thus leaves urban disaster risk mechanisms partially unexplored.This study investigated the role of the network of urban public open spaces(UPOS) in the creation and progression of urban disaster risk in earthquake-prone settlements. Through a multimethod approach that integrates quantitative and qualitative methods and explores spatial configuration, planning policies, and practices of use of UPOS in everyday and emergency scenarios, our study demonstrated that UPOS configuration plays an active role in urban disaster risk. Urban public open spaces impact risk by influencing the exposure of pedestrians and their capacity for self-protection. The study further reconceptualized spatial vulnerability at the urban scale, as the fraction of vulnerability associated to the spatial network, highlighting the interplay of planning policies and spatial practices in its production and progression. Our findings make the notion of spatial vulnerability less ambiguous at the urban scale, by viewing the variable as an imbalance in capacities and exposure that generates spatially unsafe conditions. This refined conceptualization of spatial vulnerability becomes a lens for a more granular approach to urban disaster risk reduction and city planning by identifying and integrating sociospatial considerations.

关键词： Central Italy Earthquakes Pedestrian evacuation Space syntax Spatial vulnerability Urban disaster risk

Analysis of the Spatiotemporal Variation Characteristics and Driving Factors of Land Vegetation GPP in a Certain Region of Asia

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Open Journal of Ecology 2024年第6期14卷 523-543页

作者： Zhongshuai Xia school of civil and hydraulic engineering Qinghai University Xining China

Gross primary productivity (GPP) of vegetation is a critical indicator of ecosystem growth and carbon sequestration. The spatiotemporal variation characteristics of land vegetation GPP trends in a specific region of Asia from 2001 to 2020 were analyzed by Sen and MK trend analysis methods in this study .Moreover , a GPP change attribution model was established to explore the driving influences of factors such as Leaf Area Index (LAI), Land Surface Temperature (LST), Vapor Pressure Deficit (VPD), Soil Moisture, Solar Radiation and Wind Speed on GPP. The results indicate that summer GPP values are significantly higher than those in other months, accounting for 60.8% of the annual total GPP;spring and autumn contribute 18.91% and 13.04%, respectively. In winter, due to vegetation being nearly dormant, the contribution is minimal at 7.19%. Spatially, GPP shows a decreasing trend from southeast to northwest. LAI primarily drives the spatial and seasonal variations of regional GPP, while VPD, surface temperature, solar radiation, and soil moisture have varying impacts on GPP across different dimensions. Additionally, wind speed exhibits a minor contribution to GPP across different dimensions.

关键词： Gross Primary Productivity Spatiotemporal Variations Model Driving Factors

Experimental Study on the Effect of Cyclic Preloading on the Resistance to Liquefaction of Saturated Loose Sand under Wave Loading

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Journal of Shanghai Jiaotong university(Science) 2009年第4期14卷 398-403页

作者：张振东栾茂田金丹郭莹聂影 State Key Laboratory of Coastal and Offshore engineering Dalian University of Technology Institute of Geotechnical engineering School of Civil and Hydraulic EngineeringDalian University of Technology Department of civil engineering Huaihai Institute of Technology

By using the soil static and dynamic universal triaxial and torsional shear apparatus, a series of combined cyclic shear tests are performed to simulate the rotation in the principal stress direction induced by ocean wave. The tests include the cyclic preloading tests and liquefaction tests in the second loading on saturated loose sand with a relative density of 30%. The all tests are consolidated under isotropic condition. The effect of the cyclic preloading on the resistance to liquefaction of saturated loose sands under the condition of continuous rotation in the principal stress direction is investigated. Experimental data indicate that the void ratio of saturated sands has a negligible reduction after cyclic preloading. With the increase of the intensity of cyclic preloading (in the amplitude and in the number of cycles), the resistance to liquefaction in the second loading is increased continuously under the condition that the liquefaction does not occur during the cyclic preloading. The reason is that the construction of more stable structure due to the uniformity of the void and the better interlocking of the particles when the cyclic preloading is applied to the saturated sand.

关键词：循环饱和堆载预压砂土液化波浪作用实验主应力方向松散饱和松砂

Nonlinear constitutive models of rock structural plane and their applications

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Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 790-806页

作者： Wenlin Feng Shuangjian Niu Chunsheng Qiao Dujian Zou school of civil and Environmental engineering Harbin Institute of TechnologyShenzhenChina Shenzhen Municipal engineering Corporation Shenzhen518000China school of civil engineering Beijing Jiaotong UniversityBeijing100044China

Structural planes play an important role in controlling the stability of rock engineering,and the influence of structural planes should be considered in the design and construction process of rock engineering.In this paper,mechanical properties,constitutive theory,and numerical application of structural plane are studied by a combination method of laboratory tests,theoretical derivation,and program development.The test results reveal the change laws of various mechanical parameters under different roughness and normal stress.At the pre-peak stage,a non-stationary model of shear stiffness is established,and threedimensional empirical prediction models for initial shear stiffness and residual stage roughness are proposed.The nonlinear constitutive models are established based on elasto-plastic mechanics,and the algorithms of the models are developed based on the return mapping algorithm.According to a large number of statistical analysis results,empirical prediction models are proposed for model parameters expressed by structural plane characteristic parameters.Finally,the discrete element method(DEM)is chosen to embed the constitutive models for practical application.The running programs of the constitutive models have been compiled into the discrete element model library.The comparison results between the proposed model and the Mohr-Coulomb slip model show that the proposed model can better describe nonlinear changes at different stages,and the predicted shear strength,peak strain and shear stiffness are closer to the test results.The research results of the paper are conducive to the accurate evaluation of structural plane in rock engineering.

关键词： Structural plane engineering stability Roughness Normal stress Elasto-plastic constitutive model Discrete element method

S-scheme heterojunction construction of Fe/BiOCl/BiVO4 for enhanced photocatalytic degradation of ciprofloxacin

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Progress in Natural Science:Materials International 2024年第2期34卷 290-303页

作者： Guanlong Yu Qifang Sun Yi Yang Si Chen Yuannan Long Yifu Li Shiyong Ge Dian Zheng school of hydraulic and Environmental engineering Changsha University of Science & Technology Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province school of Environmental engineering Wuhan Textile University

With the growing problem of water pollution caused by antibiotics,the development of photocatalysts with high photogenerated carrier separation efficiency is crucial.A high-efficiency microsphere Fe/BiOCl/BiVO4with Sscheme heterojunction was synthesized by solvothermal method and its ciprofloxacin（CIP） degradation performance were investigated under visible light.XRD,FT-IR,SEM,EDS,HRTEM and XPS results show that the photocatalytic have good crystallization,morphology and the formed a microsphere.The photocatalytic performance of Fe/BiOCl/BiVO4for CIP was superior to pure BiOCl and BiVO4due to the microsphere and formed heterostructure between BiOCl and BiVO4.The influencing factors of CIP degradation by Fe/BiOCl/BiVO4were investigated,and the results showed that Fe/BiOCl/BiVO4had high degradation efficiency not only at pH 5-9,but also in the presence of inorganic Cl-,NO3-and metal ions.Under the optimal conditions,the degradation rate of CIP was up to 100% in 75 min.In addition to CIP,the Fe/BiOCl/BiVO4photocatalysts degraded other organic pollutants,such as tetracycline,oxytetracycline,chlortetracycline,ofloxacin,levofloxacin,and rhodamine B,by more than 92%.The main active species were photogenerated holes（h+） and superoxide radicals（·O2-）.In addition,possible intermediates and toxicity of intermediates were analyzed and five potential pathways for CIP degradation were proposed.

关键词： BiOCl/BiVO4 Fe3+ doping Organic pollutant Photocatalysis S-scheme heterojunction