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Efficient simulation of spatially correlated non-stationary ground motions by wavelet-packet algorithm and spectral representation method

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Earthquake engineering and engineering Vibration 2024年第4期23卷 799-814页

作者： Ji Kun Cao Xuyang Wang Suyang Wen Ruizhi College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100022China Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin 150080China

Although the classical spectral representation method(SRM)has been widely used in the generation of spatially varying ground motions,there are still challenges in efficient simulation of the non-stationary stochastic vector process in *** first problem is the inherent limitation and inflexibility of the deterministic time/frequency modulation *** difficulty is the estimation of evolutionary power spectral density(EPSD)with quite a few *** tackle these problems,the wavelet packet transform(WPT)algorithm is utilized to build a time-varying spectrum of seed recording which describes the energy distribution in the time-frequency *** time-varying spectrum is proven to preserve the time and frequency marginal property as theoretical EPSD will do for the stationary *** the simulation of spatially varying ground motions,the auto-EPSD for all locations is directly estimated using the time-varying spectrum of seed recording rather than matching predefined EPSD *** the constructed spectral matrix is incorporated in SRM to simulate spatially varying non-stationary ground motions using efficient Cholesky decomposition *** addition to a good match with the target coherency model,two numerical examples indicate that the generated time histories retain the physical properties of the prescribed seed recording,including waveform,temporal/spectral non-stationarity,normalized energy buildup,and significant duration.

关键词： non-stationarity time-varying spectrum wavelet packet transform(WPT) spectral representation method(SRM) response spectrum spatially varying recordings

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Generalized response displacement methods for seismic analysis of underground structures with complex cross section

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Earthquake engineering and engineering Vibration 2023年第4期22卷 979-993页

作者： Xu Zigang Ding Linling Du Xiuli Xu Chengshun Zhuang Haiyang Jiangxi Key Laboratory of Infrastructure Safety Control in Geotechnical Engineering East China Jiaotong UniversityNanchang 330013China Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education Beijing University of TechnologyBeijing 100124China

The response displacement method(RDM)is recommended for the seismic analysis of underground structures in the transverse direction for many codes,including bases for design of structures-seismic actions for designing geotechnical works(ISO 23469)and code for seismic design of urban rail transit structures(GB 50909-2014).However,there are some obvious limitations in the application of *** and the shear stress of the soil could be approximately evaluated for the structures having a simple cross section,such as rectangular and circular *** is necessary to propose simplified seismic analysis methods for structures with complex cross *** paper refers to the idea of RDM and proposes three generalized response displacement methods(GRDM).In GRDM1,a part of the soil surrounding a structure is selected to generate a generalized underground structure with a rectangular cross section,and the same analysis model as RDM is applied to analyze the responses of the *** GRDM2,a hollow soil model without a generalized structure is used to compute the equivalent load caused by the relative displacement of the soil,and the soil-structure interaction model is applied to calculate the responses of the *** GRDM3,a continuous soil model is applied to compute the equivalent load caused by the relative displacement and shear stress of the soil,and the soil-structure interaction model is applied to analyze the responses of the structure,which is the same as the model used in *** time-history analysis method(THAM)is used to evaluate the accuracy of the proposed simplified *** show that the error of GRDM1 is about 20%,while the error is only 5%for GRDM2 and *** the three proposed methods,GRDM3 has obvious advantages regarding calculation efficiency and ***,it is recommended to use GRDM3 for the seismic response analysis of underground structures that have conventional simple or complex cross sections.

关键词： underground structures seismic analysis response displacement method equivalent seismic load complex cross section

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Mechanical properties of segment joints in subway shield tunnels by a full-scale test

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Frontiers of Structural and Civil engineering 2024年第12期18卷 1845-1864页

作者： Pengfei LI Wu FENG Xiaojing GAO Ziqi JIA Haifeng WANG Zenghui LIU Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China Nantong Railway Construction Component Co. Ltd.Nantong 226000China

In this article,the mechanical properties of tunnel joints with curved bolts are studied and analyzed using the research methods of full-scale testing and finite element numerical ***,the experiment results were analyzed to find out the development law of stress and strain of concrete in each part of the tunnel fragment when *** damage process of the joint of the tunnel fragment was described in stages,and the characteristic load value that can reflect the initial bearing capacity in each stage was ***,using the ABAQUS three-dimensional(3D)finite element numerical modeling software,a numerical model corresponding to the experiment was *** mid-span deflection was used to observe the change in loading and the destruction of each stage,comparing it to the proposed form to verify the reasonableness of the numerical ***,the numerical models were used to analyze the change in material parameters and external loads from two *** is concluded that the damage process of tunnel joints under curved bolt connection can be divided into concrete elasticity stage,inner arc cracking stage,overall joint damage stage,and ultimate joint damage stage,and the initial load of the adjacent stages is defined as the characteristic load *** concrete cracking occurs,the bolts start to become the main load-bearing components,and the bolt stress grows rapidly in stage *** strain development of the concrete on the outer arc is greater than the strain value of the concrete on the side due to mutual contact and *** parameters were changed for material properties,and it was found that increasing the concrete strength and bolt strength could improve the shield fragment joint bearing *** optimal effect of improving the mechanical properties of the shield fragment joint would be obtained when the concrete strength grade is C60,and the bolt strength grade is *** the size of the axial force and bo

关键词： shield tunnel failure mechanism bearing capacity segment joint

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A stable one-point quadrature rule for three-dimensional numerical manifold method

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Science China(Technological Sciences) 2024年第5期67卷 1401-1416页

作者： ZHANG Ning ZHENG Hong YANG Liang WU WenAn YUAN Chi School of Civil Engineering Qinghai UniversityQinghai810016China Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing100124China Faculty of Engineering China University of GeoscienceWuhan430074China

We present a numerically stable one-point quadrature rule for the stiffness matrix and mass matrix of the three-dimensional numerical manifold method(3D NMM).The rule simplifies the integration over irregularly shaped manifold elements and overcomes locking issues,and it does not cause spurious modes in modal *** essential idea is to transfer the integral over a manifold element to a few moments to the element center,thereby deriving a one-point integration rule by the moments and making modifications to avoid locking *** the stiffness matrix,after the virtual work is decomposed into moments,higher-order moments are modified to overcome locking issues in nearly incompressible and bending-dominated *** the mass matrix,the consistent and lumped types are derived by *** particular,the lumped type has the clear advantage of *** proposed method is naturally suitable for 3D NMM meshes automatically generated from a regular *** tests justify the accuracy improvements and the stability of the proposed procedure.

关键词： three-dimensional numerical manifold method quadrature rule locking mass lumping

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Deep learning-based software engineering: progress,challenges, and opportunities

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Science China(Information Sciences) 2025年第1期68卷 57-144页

作者： Xiangping CHEN Xing HU Yuan HUANG He JIANG Weixing JI Yanjie JIANG Yanyan JIANG Bo LIU Hui LIU Xiaochen LI Xiaoli LIAN Guozhu MENG Xin PENG Hailong SUN Lin SHI Bo WANG Chong WANG Jiayi WANG Tiantian WANG Jifeng XUAN Xin XIA Yibiao YANG Yixin YANG Li ZHANG Yuming ZHOU Lu ZHANG School of Journalism and Communication Sun Yat-sen University School of Software Technology Zhejiang University School of Software Engineering Sun Yat-sen University School of Software Dalian University of Technology School of Computer Science and Technology Beijing Institute of Technology Key Laboratory of High Confidence Software Technologies (Peking University) Ministry of EducationSchool of Computer Science Peking University State Key Laboratory for Novel Software Technology Nanjing University School of Computer Science and Engineering Beihang University Institute of Information Engineering Chinese Academy of Sciences School of Computer Science Fudan University State Key Laboratory of Complex & Critical Software Environment (CCSE) School of Software Beihang University School of Computer and Information Technology Beijing Jiaotong University School of Computer Science and Technology Harbin Institute of Technology School of Computer Science Wuhan University Huawei Technologies

Researchers have recently achieved significant advances in deep learning techniques, which in turn has substantially advanced other research disciplines, such as natural language processing, image processing, speech recognition, and software engineering. Various deep learning techniques have been successfully employed to facilitate software engineering tasks, including code generation, software refactoring, and fault localization. Many studies have also been presented in top conferences and journals, demonstrating the applications of deep learning techniques in resolving various software engineering tasks. However,although several surveys have provided overall pictures of the application of deep learning techniques in software engineering,they focus more on learning techniques, that is, what kind of deep learning techniques are employed and how deep models are trained or fine-tuned for software engineering tasks. We still lack surveys explaining the advances of subareas in software engineering driven by deep learning techniques, as well as challenges and opportunities in each subarea. To this end, in this study, we present the first task-oriented survey on deep learning-based software engineering. It covers twelve major software engineering subareas significantly impacted by deep learning techniques. Such subareas spread out through the whole lifecycle of software development and maintenance, including requirements engineering, software development, testing, maintenance, and developer collaboration. As we believe that deep learning may provide an opportunity to revolutionize the whole discipline of software engineering, providing one survey covering as many subareas as possible in software engineering can help future research push forward the frontier of deep learning-based software engineering more systematically. For each of the selected subareas,we highlight the major advances achieved by applying deep learning techniques with pointers to the available datasets i

关键词： deep learning software engineering software benchmark software artifact representation survey

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Numerical analysis on seismic performance of underground structures in liquefiable interlayer sites from centrifuge shaking table test

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Earthquake engineering and engineering Vibration 2024年第4期23卷 781-798页

作者： Yan Guanyu Xu Chengshun Zhang Zihong Du Xiuli Wang Xuelai Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China China Academy of Railway Sciences Corporation Limited Urban Rail Transit Center of CARSBeijing 100081China

When an underground structure passes through a liquefiable soil layer,the soil liquefaction may pose a significant threat to the structure.A centrifuge shaking table test was performed to research the seismic response of underground structures in liquefiable interlayer sites,and a valid numerical model was obtained through simulation model ***,the calibrated numerical model was used to perform further research on the influence of various distribution characteristics of liquefiable interlayers on the seismic reaction of underground *** key findings are as *** structure faces the most unfavorable condition once a liquefiable layer is located in the middle of the underground *** a liquefiable layer exists in the middle of the structure,the seismic reactions of both the underground structure and model site will increase with the rise of the thickness of the liquefiable *** inter-story drift of the structure in the non-liquefiable site is much smaller than that in the liquefiable interlayer *** inter-story drift of the structure is not only associated with the site displacement and the soil-structure stiffness ratio but also closely associated with the slippage of the soil-structure contact interface under the condition of large deformation of the site.

关键词： centrifuge shaking table test underground structure liquefiable interlayer sites seismic response validation of numerical model

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Buckling failure analysis and numerical manifold method simulation for high and steep slope: A case study

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Geohazard Mechanics 2024年第2期2卷 143-152页

作者： Ruitao Zhang Jiahao Li The Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing100124China

Buckling failure of layered rock slopes due to self-weight is common in mountain areas, especially for high andsteep slope, and it frequently results in serious disasters. Previous research has focused on qualitatively evaluatingslope buckling stability and rarely studied the whole process from bending deformation to forming landslide. Inthis work, considering the tensile and compressive characteristics of rock, the simulation of high and steep slopebucking failure evolved in Bawang Mountain, was conducted by numerical manifold method. The bucklingdeformation mechanism and progressive failure process of Bawang Mountain high steep slope were studied. Thereliability of the numerical method was verified by the comparison of theoretical calculation and field measurement data. The results show that numerical manifold method can accurately simulate high and steep slopebuckling failure process by preforming interlayer and cross joints. The process of slope buckling deformation andinstability failure can be divided into minor sliding-creep deformation, interlayer dislocation-slight bending,traction by slope toe-sharp uplift, accelerated sliding-landslide formation. Under the long-term action of selfweight, the evolution of slope buckling from formation to landslide is a progressive failure process, whichmainly contains three stages: slight bending deformation, intense uplift deformation and landslide formation.

关键词： High and steep slope Buckling failure Numerical manifold method Cross joint

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Performance and environmental impacts of deep foundation excavation in soft soils:A field and modeling-based case study in Nanjing,China

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Underground Space 2024年第5期18卷 218-238页

作者： Chenhe Ge Meng Yang Pengfei Li Mingju Zhang Zhonghao Zhang Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China China Construction Second Engineering Bureau Ltd. Beijing 100070China The Third Construction Engineering Company Ltd.of China Construction Second Engineering Bureau Beijing 100070China

This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical *** tests were conducted to determine the soil parameters used in the modified Cam–Clay(MCC)*** field monitoring means were adopted and a three-dimensional model was *** and temporal effects induced by the excavation are investigated for the deep-large foundation pit in soft *** characteristics of the enclosure structure and the surrounding environment throughout the excavation process are *** behaviors of diaphragm walls,columns,the maximum wall deflection rate,ground surface settlement,and utility pipelines were focused on and investigated during the whole excavation ***,the axial forces of the internal supports are *** on the measured and simulated data,the following main conclusions were obtained:the numerical simulation results are in good agreement with the measured values,which proves the accuracy of the model parameters;the wall and the ground surface showed the maximum displacement increment at stage 9,which was a coupled product of the"creep effect"of the soft soil in Nanjing,China and the"depth effect"of the excavation;as the excavation progressed,the ground settlement changed from a"rising"to a"spoon-shaped"trend,dvm was measured betweenδ_(vm)=0.0686%H andδ_(vm)=0.1488%H;the rebound deformation curve of the pit bottom was corrugated,and the depth of disturbance of the pit bottom after the completion of soil unloading was 2–3 times the excavation depth;the closer the pipeline is to the corner of the pit,the less the excavation process will affect the settlement of the pipeline and the less the obvious pit corner effect will occur;the support strength of the buttress and the longest corner brace should be strengthened during the actual construction process to ensure the stability of the foundation deformation.

关键词： Deep excavation Modified Cam-Clay Deformation characteristics Creep effect Corner effect

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An efficient conversion model between acceleration and pseudo-acceleration response spectra considering effects of magnitude,distance,and site class

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Earthquake engineering and engineering Vibration 2025年第1期24卷 15-30页

作者： Liu Zheng Zhao Yan-Gang Zhang Haizhong Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China Faculty of Agriculture Yamagata University1-23Wakaba-machiTsuruoka-shiYamagata 997-8555Japan

Both acceleration and pseudo-acceleration response spectra play important roles in structural seismic ***,only one of them is generally provided in most seismic ***,many studies have attempted to develop conversion models between the acceleration response spectrum(SA)and the pseudo-acceleration response spectrum(PSA).Our previous studies found that the relationship between SA and PSA is affected by magnitude,distance,and site ***,we developed an SA/PSA model incorporating these ***,this model is suitable for cases with small and moderate magnitudes and its accuracy is not good enough for cases with large *** paper aims to develop an efficient SA/PSA model by considering influences of magnitude,distance,and site class,which can be applied to cases not only with small or moderate magnitudes but also with large *** this purpose,regression analyses were conducted using 16,660 horizontal seismic records with a wider range of *** magnitude of these seismic records varies from 4 to 9 and the distances vary from 10 to 200 *** ground motions were recorded at 338 stations covering four site *** comparing them with existing models,it was found that the proposed model shows better accuracy for cases with any magnitudes,distances,and site classes considered in this study.

关键词： acceleration response spectrum pseudo-acceleration response spectrum magnitude distance site class

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Mesoscopic investigation on seismic performance of corroded reinforced concrete columns

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Earthquake engineering and engineering Vibration 2022年第4期21卷 969-985页

作者： Jin Liu Li Yanxi Zhang Renbo Du Xiuli Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100024China

In addition to the normal service loadings,engineering structures may be subjected to occasional loadings such as earthquakes,which may cause severe *** the steel rebar is corroded,the damage could be more *** investigate the seismic performance of corroded RC columns,a three-dimensional mesoscale finite element model was *** this approach,concrete was considered as a three-phase composite composed of aggregate,mortar matrix and interfacial transition zone(ITZ).The nonlinear spring were used to describe the bond slip between steel and *** degradation of the material properties of the steel rebar and cover concrete as well as the bonding performance due to corrosion were taken into *** rationality of the developed numerical analysis model was verified by the good agreement between the numerical results and the available experimental *** this basis,the effect of corrosion level,axial force ratio and shear-span ratio on the seismic performance of corroded RC columns,including lateral bearing capacity,ductility,and energy consumption,were explored and *** simulation results indicate that the mesoscopic method can consider the heterogeneity of concrete,to more realistically and reasonably reflect the destruction process of structures.

关键词： reinforcement corrosion reinforced concrete column meso-scale finite element analysis seismic behavior

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