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Numerical analysis on seismic response and failure mechanism of articulated pile−structure system in a liquefiable site from shaking-table experiments

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1117-1133页

作者： Pengfei DOU Hao LIU Chengshun XU Jinting WANG Yilong SUN xiuli du Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education Beijing University of TechnologyBeijing 100124China

This study investigates the seismic response and failure mode of a pile-structure system in a liquefiable site by employing a numerical simulation model combined with the shaking-table results of a soil-pile-structure dynamic *** pile and soil responses obtained from the numerical simulations agreed well with the experimental *** slopes of the dynamic shear-stress-shear-strain hysteretic curves at different positions also exhibited a decreasing trend,indicating that the shear strength of the soil in all parts of the foundation *** peak acceleration of the soil and pile was not clearly amplified in the saturated sand layer but appeared to be amplified in the top *** maximum bending moments appeared in the middle and lower parts of the pile shaft;however,the shear forces at the corresponding positions were not *** can be observed from the deformation mode of the pile-group foundation that a typical bending failure is caused by an excessive bending moment in the middle of the pile shaft if the link between the pile top and cap is articulated,and sufficient attention should be paid to the bending failure in the middle of the pile shaft.

关键词： numerical simulation soil liquefaction pile foundation shaking-table experiment seismic responses failure model

Progressive fragmentation of granular assemblies within rockslides: Insights from discrete-continuous numerical modeling

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Journal of Mountain Science 2024年第4期21卷 1174-1189页

作者： JIANG Hui ZHOU Yuande WANG Jinting du xiuli HUANG Hailong Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China. Key Laboratory of the Hydrosphere Sciences of the Ministry of Water Resources Tsinghua UniversityBeijing 100084China China Three Gorges Construction Management Co. Ltd.Chengdu 610000China

Rock fragmentation plays a critical role in rock avalanches,yet conventional approaches such as classical granular flow models or the bonded particle model have limitations in accurately characterizing the progressive disintegration and kinematics of multi-deformable rock blocks during *** present study proposes a discrete-continuous numerical model,based on a cohesive zone model,to explicitly incorporate the progressive fragmentation and intricate interparticle interactions inherent in *** rock granular assemblies are released along an inclined plane and flow onto a horizontal *** numerical scenarios are established to incorporate variations in slope angle,initial height,friction coefficient,and particle *** evolutions of fragmentation,kinematic,runout and depositional characteristics are quantitatively analyzed and compared with experimental and field data.A positive linear relationship between the equivalent friction coefficient and the apparent friction coefficient is *** general,the granular mass predominantly exhibits characteristics of a dense granular flow,with the Savage number exhibiting a decreasing trend as the volume of mass *** process of particle breakage gradually occurs in a bottom-up manner,leading to a significant increase in the angular velocities of the rock blocks with increasing *** simulation results reproduce the field observations of inverse grading and source stratigraphy preservation in the *** propose a disintegration index that incorporates factors such as drop height,rock mass volume,and rock *** findings demonstrate a consistent linear relationship between this index and the fragmentation degree in all tested scenarios.

关键词： Rock fragmentation Rockslide Numerical modelling Discrete-continuous modelling Runout Cohesive zone model

Synthesis of carbon dots with predictable photoluminescence by the aid of machine learning

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Nano Research 2024年第3期17卷 1984-1989页

作者： Chenyu Xing Gaoyu Chen Xia Zhu Jiakun An Jianchun Bao Xuan Wang Xiuqing Zhou xiuli du Xiangxing Xu Jiangsu Key Laboratory of Biofunctional Materials Jiangsu Key Laboratory of New Power BatteriesSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China School of Mathematical Sciences Nanjing Normal UniversityNanjing 210023China State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210093China

Carbon dots(CDs)have wide application potentials in optoelectronic devices,biology,medicine,chemical sensors,and quantum techniques due to their excellent fluorescent ***,synthesis of CDs with controllable spectrum is challenging because of the diversity of the CD components and *** this report,machine learning(ML)algorithms were applied to help the synthesis of CDs with predictable photoluminescence(PL)under the excitation wavelengths of 365 and 532 *** combination of precursors was used as the *** PL peaks of the strongest intensity(λ_(s))and the longest wavelength(λ_(l))were used as target *** six investigated ML models,the random forest(RF)model showed outstanding)performance in the prediction of the PL peaks.

关键词： carbon dots(CDs) synthesis photoluminescence(PL) machine learning(ML) PL prediction

面向未来低碳道路养护的超薄罩面功能性研究综述

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Engineering 2024年第1期32卷 82-98页

作者： Meng Guo Rui Zhang xiuli du Pengfei Liu State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China Institute of Highway Engineering RWTH Aachen UniversityAachen 52074Germany

Highway maintenance mileage reached 5.25 million kilometers in China by ***-thin overlay is one of the most commonly used maintenance technologies,which can significantly enhance the economic and environmental benefits of *** promote the low-carbon development of ultrathin overlays,this paper mainly studied the mechanism and influencing factors of several ultra-thin overlay ***,the skid resistance,noise reduction,rutting resistance,and crack resistance of ultrathin overlays were *** results indicated that the high-quality aggregates improved the skid and rutting resistance of ultra-thin overlay by 5%-20%.The optimized gradations and modified binders reduced noise of ultra-thin overlay by 0.4-6.0 *** high viscosity modified binders improved the rutting resistance of ultra-thin overlay by about 10%-130%.Basalt fiber improved the cracking resistance of ultra-thin overlay by more than 20%.due to the thinner thickness and better road performance,the performance-based engineering cost of ultra-thin overlay was reduced by about 30%-40%compared with conventional ***,several environmentally friendly functions of ultra-thin overlay were investigated,including snow melting and deicing,exhaust gas purification and pavement *** lower thickness of ultra-thin overlay was conducive to the diffusion of chloride-based materials to the pavement ***,the snow melting effect of self-ice-melting was *** addition,the ultra-thin overlay mixture containing photocatalytic materials could decompose 20%-50%of the exhaust *** colored ultra-thin overlay was able to reduce the temperature of the pavement by up to 8.1℃.The temperature difference between the upper and lower surfaces of the ultra-thin overlay containing thermal resistance materials could reach up to 12.8℃.In addition,numerous typical global engineering applications of functional ultra-thin overlay were *** review can help better under

关键词： Road maintenance Ultra-thin overlay Snow melting and deicing Exhaust gas purification Pavement cooling Low-carbon

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结构空间约束对钢筋混凝土梁受弯性能的影响

东南大学学报（自然科学版） 2024年第4期54卷 885-893页

作者：雷宇霜金浏杜修力北京工业大学城市建设学部北京100124

为探究结构空间约束对框架结构屈服机制的影响,借助多尺度数值方法,建立了具有不同边界条件的钢筋混凝土(reinforced concrete,RC)梁模型.定量分析了端部约束及添加现浇楼板对RC框架梁刚度和受弯承载力,即试件所能承受的最大弯矩的影响... 详细信息

为探究结构空间约束对框架结构屈服机制的影响,借助多尺度数值方法,建立了具有不同边界条件的钢筋混凝土(reinforced concrete,RC)梁模型.定量分析了端部约束及添加现浇楼板对RC框架梁刚度和受弯承载力,即试件所能承受的最大弯矩的影响,揭示了端部约束及现浇楼板对RC梁弯曲机制的影响机理.此外,对各国规范计算的受弯承载力进行对比分析.结果表明,结构空间约束会影响RC框架梁的破坏形态.固支梁的刚度和受弯承载力显著高于简支梁,固支梁的受弯承载力和刚度最高可达简支梁的3.06倍和4.10倍.添加现浇楼板可显著提高梁的受弯承载力与刚度.各国规范可准确地计算简支梁的受弯承载力.然而,计算的固支梁及楼盖梁的受弯承载力极其保守,剪跨比为5.0的固支加板梁的受弯承载力模拟值分别是中国、美国和加拿大规范值的6.25倍、6.76倍和6.06倍.

关键词：钢筋混凝土梁结构空间约束端部约束现浇楼板强梁弱柱细观模拟

考虑箍筋与CFRP布相互作用的CFRP布加固RC梁受剪承载力细观研究

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建筑结构学报 2024年第3期45卷 208-219页

作者：金浏张江兴李冬杜修力北京工业大学城市减灾与防灾防护教育部重点实验室北京100124

为揭示CFRP布加固RC梁剪切破坏机理,采用同时考虑混凝土材料细观非均质性、钢筋与混凝土相互作用、CFRP布与混凝土相互作用的数值模拟方法,建立CFRP布加固RC梁三维细观数值分析模型。分析了箍筋、CFRP布及其相互作用对梁剪切破坏的影响... 详细信息

为揭示CFRP布加固RC梁剪切破坏机理,采用同时考虑混凝土材料细观非均质性、钢筋与混凝土相互作用、CFRP布与混凝土相互作用的数值模拟方法,建立CFRP布加固RC梁三维细观数值分析模型。分析了箍筋、CFRP布及其相互作用对梁剪切破坏的影响,建立了CFRP布加固RC梁截面名义抗剪强度修正计算式。研究表明:梁受剪承载力随配箍率(0%、0.2%、0.5%、0.8%)和配纤率(0%、0.066 8%、0.133 6%、0.267 2%)增大均有不同程度提高,但提高幅度随配箍率和配纤率增加而减小;箍筋应变和CFRP布应变均与主斜裂缝位置紧密相关,越靠近主斜裂缝位置的应变越大,且峰值应变随配箍率和配纤率增加而减小,当配纤率由0.066 8%增至0.267 2%时,CFRP布应变降低了45.9%,当配箍率由0.2%增至0.8%时,CFRP布应变减小了30.6%;箍筋和CFRP布之间存在不利相互作用,其对梁的剪切贡献不能简单叠加;建立的考虑配箍率、配纤率及其相互作用影响的CFRP布加固RC梁截面名义抗剪强度修正计算式计算值与试验值的误差小于20%,较为准确合理,可用于预测CFRP布加固RC梁的受剪承载力。

关键词：钢筋混凝土梁配箍率 CFRP配纤率细观分析剪切性能

钢筋及BFRP筋混凝土深受弯构件受剪性能及尺寸效应对比分析:试验研究

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土木工程学报 2024年第4期57卷 1-11,22页

作者：金浏宋博张江兴杜修力北京工业大学城市减灾与防灾防护教育部重点实验室北京100124

文章旨在研究并对比钢筋及BFRP筋(玄武岩纤维增强筋)混凝土深受弯构件受剪性能及尺寸效应的异同,对4根钢筋混凝土深受弯构件及4根BFRP筋混凝土深受弯构件(梁高为300~1200mm)进行了剪切破坏试验。对比分析了荷载-位移曲线、斜裂缝宽度、... 详细信息

文章旨在研究并对比钢筋及BFRP筋(玄武岩纤维增强筋)混凝土深受弯构件受剪性能及尺寸效应的异同,对4根钢筋混凝土深受弯构件及4根BFRP筋混凝土深受弯构件(梁高为300~1200mm)进行了剪切破坏试验。对比分析了荷载-位移曲线、斜裂缝宽度、混凝土应变、纵筋应变及腹筋应变随结构尺寸变化的发展趋势。揭示了钢筋及BFRP筋混凝土深受弯构件抗剪强度尺寸效应规律,并分析了设计规范和计算方法的适用性。研究表明:(1)BFRP筋混凝土深受弯构件的极限荷载约为钢筋混凝土深受弯构件的0.3~0.5倍,而挠度约为钢筋混凝土深受弯构件的1.4~1.7倍;(2)梁高从300mm增至1200mm时(试验梁的水平及竖向腹筋率均为0.51%),钢筋混凝土深受弯构件的名义极限抗剪强度下降34.0%,而BFRP筋混凝土深受弯构件下降45.7%;(3)对于大尺寸构件的抗剪承载力,设计规范的计算结果安全储备不足,未能合理考虑尺寸效应;(4)提出的尺寸效应理论公式可以定量描述结构尺寸对钢筋及BFRP筋混凝土深受弯构件名义极限抗剪强度的影响。

关键词：深受弯构件 BFRP筋剪切破坏受剪性能尺寸效应

配筋率与质量比对FRP-RC梁冲击响应与损伤的影响

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东南大学学报（自然科学版） 2024年第4期54卷 816-826页

作者：金浏郑敏张仁波杜修力北京工业大学城市减灾与防灾防护教育部重点实验室北京100124

基于考虑应变率效应的三维数值模型,对玄武岩纤维增强复材筋混凝土(BFRP-RC)梁的抗冲击性能进行了研究.分析了冲击体与FRP-RC梁质量比、配筋率等因素对冲击响应的影响规律.结果表明,随着质量比增大,FRP筋混凝土梁的破坏模式从弯曲破坏... 详细信息

基于考虑应变率效应的三维数值模型,对玄武岩纤维增强复材筋混凝土(BFRP-RC)梁的抗冲击性能进行了研究.分析了冲击体与FRP-RC梁质量比、配筋率等因素对冲击响应的影响规律.结果表明,随着质量比增大,FRP筋混凝土梁的破坏模式从弯曲破坏转变为剪切破坏,但是配筋率的改变并不影响梁的破坏模式.由于BFRP筋弹性模量低,并且没有屈服阶段,故即使在梁损伤比较严重的情况下,BFRP筋的应变和BFRP筋梁的位移也会发生较大恢复.在冲击过程中,冲击力时程曲线的形状与质量比之间的规律不随配筋率而改变.此外,以剩余承载力为基准,建立了以频率变化、损伤因子和峰值位移为指标的损伤评估方法,为实际工程中FRP筋混凝土梁构件的灾后处置提供理论基础.

关键词：落锤冲击损伤评估数值模拟 FRP-RC梁质量比

震后RC桥墩竖向承载力最优工程需求参数的选取方法

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土木工程学报 2024年第4期57卷 59-70页

作者：董慧慧马睿韩强杜修力北京工业大学桥梁工程安全与韧性全国重点实验室北京100124

桥墩结构的震后竖向承载力是评估梁式桥梁震后通行功能的重要指标,但其难以测量。为了快速定量地评估桥梁结构的震后通行能力,对评估梁式桥梁结构震后竖向承载力的最优工程需求参数(EDP)进行了系统地研究。首先选取与墩柱残余侧移和损... 详细信息

桥墩结构的震后竖向承载力是评估梁式桥梁震后通行功能的重要指标,但其难以测量。为了快速定量地评估桥梁结构的震后通行能力,对评估梁式桥梁结构震后竖向承载力的最优工程需求参数(EDP)进行了系统地研究。首先选取与墩柱残余侧移和损伤相关的5个EDPs,通过对考虑了材料不确定性的RC桥墩进行Pushover分析和动力时程分析得到5个EDPs,进一步对震后的桥墩进行Pushdown分析获取震后竖向承载力。然后采用回归模型对所选EDPs与震后竖向承载力损失比的关系曲线进行回归分析,选取竖向承载力损失比关系曲线的最优回归模型为在ln(x)-y坐标系中的正态累积函数模型,进一步通过最优EDP评价准则对评估竖向承载力损失比的5个EDPs进行评价分析。评价结果表明:当考虑震后可计算性时,峰值侧移率最优;当考虑震后可测性时,残余侧移率最优;当考虑余震时,改进的Park-Ang指标最优。通过选取的最优EDP可以建立桥梁结构功能指标与抗震性能指标之间的联系,为进一步发展和完善桥梁结构的抗震韧性评估和设计提供参考。

关键词：桥墩震后通行能力竖向承载力损失最优EDP 残余侧移率损伤程度