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The surge-heave-pitch coupling motions of the Φ- type vertical axis wind turbine supported by the truss Spar floating foundation

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Journal of Hydrodynamics 2019年第4期31卷 669-681页

作者： Ying Guo Li-qin Liu Yan Li Chang-shui Xiao You-gang Tang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University Tianjin 300072 China

The motions of the floating vertical axis wind turbine (VAWT) with consideration of the coupling between the aerodynamics and the hydrodynamics are calculated in this paper. The surge-heave-pitch coupling nonlinear equations of the floating VAWT are established. The aerodynamic loads are obtained by applying the double-multiple-stream tube theory with consideration of the dynamic stall and the floating foundation motion. The motion performances of a 5 MW Φ - Darrieus type floating VAWT are studied with its foundation of the Spar type with heave plates. It is shown that the amplitude of the heave motion of the floating VAWT is small when the heave plates are equipped. The effects of the wind and wave loads on the floating VAWT motions are assessed. The results show that the mean values of the surge and the pitch of the floating VAWT are mainly related to the wind loads;the standard deviations of the surge, the heave, and the pitch are mainly related to the wave loads. In the regular wave cases, the frequencies of the surge, the heave and the pitch are dominated by the wave frequencies, and the components of the 2P responses (caused by the aerodynamic loads) of the pitch are small. The 2P responses of the pitch are more significant in the irregular wave cases as compared with those in the regular wave cases.

关键词： Floating VAWT truss Spar floating foundation surge-heave-pitch motions aerodynamics regular waves irregular waves

Deformation analysis and safety assessment of existing metro tunnels affected by excavation of a foundation pit

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Underground Space 2021年第4期6卷 421-431页

作者： Shuaihua Ye Zhuangfu Zhao Denqun Wang School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Key Laboratory of Disaster Mitigation in Civil Engineering of Gansu Province Lanzhou University of TechnologyLanzhou 730050China Architectural Design Institute Hefei University of Technology Hefei 230000China

The excavation of a foundation pit considerably affects the adjacent structures and underground pipelines owing to the change in the stress state of the surrounding soil,resulting in *** study of an actual engineering case was conducted to examine the influence of excavation on the deformation of adjacent subway *** finite element analysis software PLAXIS 3D was used to simulate the entire excavation *** structural design of the foundation pit was optimized based on the simulation results to ensure the stability of the foundation pit and the safety of the existing subway tunnel ***,the safety evaluation of the excavation of the foundation pit that caused the deformation of the adjacent subway tunnel was *** influence of the excavation and unloading of the foundation pit on the subway tunnel is closely related to the distance between the subway and the foundation pit,the amount of earthwork excavated at one time,and the engineering geological *** results of this paper can provide useful reference for the design optimization and safety assessment of similar projects.

关键词： foundation pit excavation Deformation Metro tunnel Numerical simulation Safety assessment

GENERAL SOLUTION FOR LARGE DEFLECTION PROBLEMS OF NONHOMOGENEOUS CIRCULAR PLATES ON ELASTIC foundation

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Applied Mathematics and Mechanics(English Edition) 1992年第11期13卷 995-1007页

作者：纪振义叶开沅 Anhui Architectural Industry College Hefei Lanzhou University Lanzhou

A new method was presented here based on authors' previous work. This new method can be used to solve the arbitrary nonlinear system of differential equations with variable coefficients. By this method, the general solution for large deformation of nonhomogeneous circular plates resting on a elastic foundation was derived, and its convergence was proved. Finally, the only thing necessary to solve is a set of nonlinear algebraic equations with three unknowns. The solution obtained by the present method has large convergence range and the computation is simpler and more rapid than other numerical methods. The numerical examples indicate that satisfactory results of stress resultants and displacements can be obtained by the present method. The correctness of the theory in this paper has been confirmed.

关键词： Bending (deformation) Differential equations foundations Nonlinear equations Soil structure interactions

Supporting Earth Pressures for foundation Excavation Considering Suction Stress of Soil

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Journal of Shanghai Jiaotong university(Science) 2020年第4期25卷 486-494页

作者： LI Jingpei CAO Xiaobing LI Lin Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Department of Geotechnical EngineeringTongji UniversityShanghai 200092China

The infiltration,evaporation and variation of the groundwater table have significant effects on the suction stress of the soils and the supporting earth pressures of the foundation *** distribution of the suction stresses above the ground water table is derived under different fluxes at the ground surface,according to the soil-water characteristic parameters and the effective degree of *** consideration of the cohesive stress formed from the soil suction stress and the relevant anti sliding effect,the calculation model of supporting earth pressures for foundation excavation is established by the variational limit equilibrium method under the steady flow *** evolution of the supporting earth pressures is studied in detail for foundation excavation under different fluxes at the ground *** effects of the soil-water characteristic parameters,the ground water table and the internal friction angle on the supporting earth pressures are *** results show that the suction stress is reduced because of the infiltration,and thus the supporting earth pressure *** larger the air-entry pressures and the pore size are,the smaller the supporting earth pressures *** higher the ground water table is,the larger the supporting earth pressures *** order to reduce the construction risk,the effects of the suction stress and the evolution of the potential critical sliding surface should be considered during the calculation of the supporting earth pressures.

关键词： effective degree of saturation suction stress supporting earth pressure variational limit equilibrium method

Numerical Simulation and Field Monitoring Analysis for Deep foundation Pit Construction of Subway Station

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Structural Durability & Health Monitoring 2022年第4期16卷 397-416页

作者： Longyu Zhang Jiming Zhu Department of Resources and Civil Engineering Shandong University of Science and TechnologyTai’an271019China

To investigate the effect of deep foundation pit excavation on the stability of retaining structure, a subway stationin the city of Jinan was selected as a project, and a FLAC3D-based three dimensional model was developed fornumerical simulation. The horizontal displacement of the retaining structure, the axial force of the support, andthe vertical displacement of the column were studied and compared to the collected data from the field. The findingsindicate that when the foundation pit is excavated, the maximum deformation of the retaining structure progressivelydecreases from the top, the distortion of the retaining structure gradually rises, and the final maximumdeformation is around 17 meters deep. In each layer of support, the largest axial force support is located in thefirst reinforced concrete support;the uplift of the pit bottom caused by soil unloading plays a primary role in thevertical displacement of the column, and the column exhibits an upward trend under all construction *** compared to the measured data, the generated findings are comparable and the fluctuation trend is extremelyconsistent. The findings of this article may give technical direction for the development of subway stationswith a comparable engineering basis.

关键词： Subway station deep foundations pit numerical simulation field monitoring maximum horizontal displacement

Controlled rocking pile foundation system with replaceable bar fuses for seismic resilience

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Earthquake Engineering and Engineering Vibration 2022年第3期21卷 683-696页

作者： Cheng Zhao Li Shuai Wang Jingquan Bridge Engineering Research Center of Southeast University School of Civil EngineeringSoutheast UniversityNanjing 210096China

Bridges designed following a conventional approach minimize the risk of collapse,but often require challenging,costly,and time-consuming restoration after an earthquake *** new seismic design philosophy requires bridges to maintain functionality even after severe *** this context,this paper proposes a controlled rocking pile foundation(CRPF)system and numerically evaluates bridges′degree of seismic *** CRPF system allows a pile cap to rock on a pile foundation and dissipate seismic energy through inelastic deformations of replaceable bar fuses that connect a pile cap and *** the conceptual design of the CRPF system,two analytical models were developed for a bridge pier utilizing the CRPF system and a pier designed to develop a plastic hinge in its *** analytical results indicate that,after experiencing a severe earthquake,a conventionally designed bridge pier sustained substantial damage in its column and exhibited significant residual *** contrast,a pier using the CRPF system showed negligible residual displacement and maintained elastic behavior except,as expected,for bar *** damaged fuses can be rapidly replaced to recover bridge seismic resistance following an ***,the CRPF system helps to achieve the desired postearthquake performance objectives.

关键词： seismic resilience bridges pier controlled rocking pile foundation repairable bar fuse

Dynamic Analysis of Submarine Pipelines on an Elastic / Viscoelastic foundation

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China Ocean Engineering 1993年第3期8卷 333-340页

作者： Lei, Xinhai Qian, Qin Huang, Yuying Zhu, Dashan Wuhan China

This paper presents a new finite element method for solving static and dynamic problems in laying operation of pipelines. The effect of the viscoelastic soil behavior is considered by using the Pasternak foundation mo... 详细信息

关键词： Boundary value problems Computer aided analysis Dynamics Finite element method foundations Mathematical models Soil mechanics Viscoelasticity

Structural Strength Analysis of a Tri-Floater Floating foundation for Offshore VAWT

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Journal of Ocean University of China 2018年第4期17卷 753-762页

作者： LIU Liqin ZHAO Haixiang XU Wanhai YUAN Rui GUO Ying State Kev Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

Vertical axis wind turbines(VAWTs) are advantageous for the development of large-scale offshore wind power because the drive system is located at the bottom of the turbine. This study investigates the structural strength of a tri-floater floating foundation supporting a 2.6 MW Darrieus VAWT. Finite element models of the floating foundation were developed using space plate-beam elements. The environmental loads, such as the aerodynamic loads, static wind loads, and wave-current loads, were considered. The general strengths of the floating foundation were calculated for the normal operating case(a cut-out wind speed of 25 m s^(-1) and blade rotation of 12 r min^(-1) were used to analyze the most unfavorable loads) and an extreme case(wind speed of 40 m s^(-1) and parked blades), and the weak components of the structure were analyzed. The results show that the floating foundation meets the strength requirements and the structural stress is highest when the wave, wind, and current are in a collinear direction. The main and secondary supporting bars transmit the loads between the stand columns and the tower foundation, and their stresses are higher than those in the other components. In the actual design, these supporting bars should be strengthened. The aerodynamic loads are very important and should be considered in the structural strength analysis of the floating foundation and the floating wind turbine system.

关键词： vertical axis wind turbine tri-floater floating foundation strength analysis finite element method structural stress

Study on Deformation Law of Circular foundation Under Combined Loading

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Journal of Ocean University of China 2014年第1期13卷 51-56页

作者： ZHANG Qiyi SHI Hongda Department of Ocean Engineering College of Engineering Ocean University of China Key Laboratory of Ocean Engineering of Shandong Province

The foundations of some ocean engineering structures are built to withstand not only the vertical gravity load V, but also the horizontal load H induced by sea waves and current. The horizontal load includes the concentrated force load, the moment load M, and the torque load T termed also as combined loading. It is of academic and engineering significance to study the deformation law of submarine seabed due to combined loading. On the basis of the three-dimensional elastic mechanics solution of circular foundation, numerical methods are used to analyze the deformation law of submarine soil under circular foundation with six degrees of freedom. The finite element analysis results give the elastic deformation law of soil in three dimensional spaces, modify the theoretical elasticity solution, and presents nonlinear soil deformation mechanism under the circular foundation with six degrees of freedom.

关键词： degrees of freedom circular foundation deformation law combined loading elastic mechanics solution