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Wide angle reflections in OBC seismic physical model experiment

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Applied Geophysics 2012年第2期9卷 207-212,236页

作者：杨正华黄翼坚吴永新长安大学地测学院地球物理系西安710054 西北大学地质学系西安710069 长安大学地学实验中心西安710054

Wide angle acquisition has been taken as a significant measure to obtain high quality seismic data and is getting greater attention, In this paper, we discuss ocean bottom cable （OBC） seismic wide angle reflections on the basis of a layered model experiment. Some experiment results don＇t support theoretical conclusions. The main experimental conclusions are： 1. Wide angle reflection energies are stronger than non-wide-angle reflections （up to twice as strong） but there is a big difference between observations and theoretical calculations that suggest the wide angle reflection energies are 15 times the non- wide-angle reflection energy. The reflection energy increases gradually rather than sharply as the theoretical calculations suggest. 2. The reflection events remain hyperbolic when the offset increases. 3. Wide angle reflection dominant frequency is about 20-30% less than non- wide-angle reflections and decreases as the offset increases. The non-wide-angle reflection dominant frequency shows no obvious variation for small offsets. 4. There is no wave shape mutation or polarity reversal near the critical angle. 5. The reflection event group features are the same for both cases of incidence angle greater and less than the critical angle. 6. Direct arrivals, multiples, and water bottom refractions influence the wide angle reflections of the sea floor.

关键词： ocean bottom cable physical model wide angle refection model experiment

Numerical simulation of liquid sloshing in a spherical tank by MPS method

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Journal of Hydrodynamics 2024年第2期36卷 232-240页

作者： Cong-yi Huang Ji-fei Wang Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamic Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Aerospace System Engineering Institute Shanghai201109China

This paper investigates the sloshing phenomena in a spherical liquid tank using the moving particle semi-implicit(MPS)method,a crucial study in fluid *** from previous research focused on rectangular or LNG tanks,this work explores the unique motion patterns inherent to spherical *** accuracy of our in-house MPS solver MLParticle-SJTU is validated against experimental data and finite volume method(FVM).And the MPS method reveals a closer alignment with experimental outcomes,which suggests that MPS method is particularly effective for modeling complex,non-linear fluid *** the fluid’s response to excitation at its natural frequency is simulated,showcasing vigorous sloshing and rotational *** analyses of the fluid motion are conducted by drawing streamline diagrams,velocity vector diagrams,and vorticity *** fluid’s motion response is explored using both time-domain and frequency-domain curves of the fluid centroid,as well as the sloshing force.

关键词： Moving particle semi-implicit(MPS)method spherical tank liquid sloshing model experiment

model experiments on Melting of Alloys with Low Melting Temperature in a Medium with High Melting Temperature

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Journal of Iron and Steel Research International 1999年第2期6卷 1-9页

作者： Becker Jens-Ulrik Oeters Franz Thyssen-Krupp Stahl GmbH Technical University Berlin

experiments of alloy melting were carried out in water/HCl H 2O eutectic model system. The eutectic has a solid liquid equilibrium temperature of -74 ℃. 5 cm diameter spheres of the eutectic in which three thermocouples in the core, on the edge and in the middle between them had been positioned were cooled to -196 ℃ in liquid nitrogen. After cooling the spheres were immersed into water of 10 ℃, and the changes of temperatures with time in the three thermocouples were measured. In some experiments the temperature on the outer side of the spheres where an ice shell grew up was also measured. In these experiments, the growing rate of the shell was additionally determined. The results for the first minute of the melting process, where the system can be considered as one dimensional, were described by an exact solution of Fouriers equation. The density of liquid ferromanganese at 1 500 ℃ was measured.

关键词： alloy melting model experiment

Spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway with model experiments

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International Journal of Mining Science and Technology 2016年第5期26卷 895-902页

作者： Li Yuanhai Zhang Qi Lin Zhibin Wang Xiaodong astate Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining & Technology Xuzhou 221116 China School of Mechanics and Civil Engineering China University of Mining & Technology Xuzhou 221116 China School of Civil Engineering Southeast University Nanjing 210096. China Changsha Engineering and Research Institute Ltd. of Nonferrous Metallurgy Changsha 410011 China

A series of plane-strain physical model experiments are carried out to study the spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway, which is subjected to the pressure induced by the mining process. The digital photogrammetry technology and large deformation analysis method are applied to measure the deformation and fracture of surrounding rocks. The experimental results indicate that the deformation and fracture of coal pillars are the cause to the instability and failure of the surrounding rocks. The spatiotemporal evolution rule of the rock deformation and fracture surrounding gob-side roadway is obtained. The coal pillar and the roof near coal pillar should be strengthened in support design. The engineering application results also can provide a useful guide that the combined support with wire meshes, beam, anchor bolt and cable is an effective method.

关键词： model experiment Digital photogrammetry Gob-side roadway Spatiotemporal evolution rule Stability control and combined support

Bearing capacity of foundation on slope determined by energy dissipation method and model experiments

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Journal of Central South University of Technology 2007年第1期14卷 125-128页

作者：杨小礼王志斌邹金锋李亮 School of Civil and Architectural Engineering Ce ntral South University

To determine the ultimate bearing capacity of foundations on sloping ground surface in practice, energy dissipation method was used to formulate the beating capacity as programming problem, and full-scale model experiments were investigated to analyze the performance of the soil slopes loaded by a strip footing in laboratory. The soil failure is governed by a linear Mohr-Coulomb yield criterion, and soil deformation follows an associated flow rule. Based on the energy dissipation method of plastic mechanics, a multi-wedge translational failure mechanism was employed to obtain the three bearing capacity factors related to cohesion, equivalent surcharge load and the unit gravity for various slope inclination angles. Numerical results were compared with those of the published solutions using finite element method and those of model experiments. The bearing capacity factors were presented in the form of design charts for practical use in engineering. The results show that limit analysis solutions approximate to those of model tests, and that the energy dissipation method is effective to estimate bearing capacity of soil slope.

关键词： energy dissipation bearing capacity soil slope model experiment

Study on the optimal operation mode of ventilation system during metro double-island platform fire

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Building Simulation 2021年第3期14卷 779-792页

作者： Zeng Long Yuxuan Yang Chang Liu Maohua Zhong Institute of Public Safety Research Department of Engineering PhysicsTsinghua UniversityBeijing 700084China Beijing Key Laboratory of City Integrated Emergency Response Science Beijing 700084China

Large metro transfer stations have been widely constructed in China,among which the double-island station faces the serious fire safety issues owing to its large passenger *** this paper,simulation cases were carried out to investigate the effectiveness of different ventilation modes by jointly operating tunnel ventilation fan(TVF)and platform screen doors(PSD)under two typical fire scenarios in the *** numerical model was established by Fire Dynamics Simulator software and verified via reduced-scale model *** results indicate that the TVF mode of supplying at the end near fire and exhausting at the other end is superior to that of exhausting at both ***,activating more PSD and TVF on the both sides of platform will restrict smoke in one end to the greater *** a fire in the middle of the platform,opening all PSD near tunnel-2 and TVF in tunnel-2 and tunnel-3 is the most appropriate *** during a fire at the left end of the platform,activating all PSD and TVF on both sides is the optimal operation *** conclusions can provide guidance for smoke control design and on-site emergency ventilation operation in double-island platform fire.

关键词： metro double-island platform fire ventilation mode numerical simulation model experiment

Design and experimental verification of a new multi-functional bridge seismic isolation bearing

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第12期13卷 904-914页

作者： Chen-xi XING Hao WANG Ai-qun LI Ji-rong WU MOE Key Laboratory of Concrete and Prestressed Concrete Structures Southeast UniversityNanjing 210096China

A new multi-functional bridge seismic isolation bearing(MFBSIB) is designed and its mechanical model is developed in this *** an upper sliding device and a lower energy dispassion isolation device effectively,the new MFBSIB can adjust the deformation caused by temperature,vehicle breaks,and concrete creep,etc.,in addition to dissipating *** switch of 'slide-isolation' is achieved and the efficiency of both upper and lower parts is validated through experiment with a *** shear performance curve established in this paper is verified to be efficient in describing the mechanical characteristics of the bearing through *** is proved through both numerical calculation and experimental analysis that the new MFBSIB is endowed with enough vertical rigidity,good energy dissipation ability,stable overall performance,and good realization in expected *** performance is slightly influenced by shear stress,while affected by vertical pressure,loading frequency,slide limit,etc.,*** results could provide reference for study and application of the new MFBSIB.

关键词： Seismic isolation bearing Sliding device Finite element analysis model experiment Bridge

experiment Study of Dynamics Response for Wind Turbine System of Floating Foundation

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China Ocean Engineering 2015年第6期29卷 835-846页

作者：唐友刚宋凯王宾 State Key Laboratory of Hydraulic Engineering Simulation and Safety School of Civil EngineeringTianjin University

The floating foundation is designed to support a 1.5 MW wind turbine in 30 m water depth. With consideration of the viscous damping of foundation and heave plates, the amplitude-frequency response characteristics of the foundation are studied. By taking into account the elastic effect of blades and tower, the classic quasi-steady blade-element/momentum（BEM） theory is used to calculate the aerodynamic elastic loads. A coupled dynamic model of the turbine-foundationmooring lines is established to calculate the motion response of floating foundation under Kaimal wind spectrum and regular wave by using the FAST codes. The model experiment is carried out to test damping characteristics and natural motion behaviors of the wind turbine system. The dynamics response is tested by considering only waves and the joint action of wind and waves. It is shown that the wind turbine system can avoid resonances under the action of wind and waves. In addition, the heave motion of the floating foundation is induced by waves and the surge motion is induced by wind. The action of wind and waves is of significance for pitch.

关键词： offshore wind turbine semi-submersible floating foundation coupled dynamic model model experiment

Early warning model for slope debris flow initiation

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Journal of Mountain Science 2018年第6期15卷 1342-1353页

作者： LI Ming-li JIANG Yuan-jun YANG Tao HUANG Qiang-bing QIAO Jian-ping YANG Zong-ji Key Laboratory of Mountain Hazards and Earth Surface Process of Chinese Academy of Sciences Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Chengdu Center of Hydrogeology and Engineering Geology of Sichuan Bureau of Geology&Mineral Resources Chengdu 610000China Department of Geological Engineering Chang'an UniversityXi'an 710054China

Early warning model of debris flow is important for providing local residents with reliable and accurate warning information to escape from debris flow hazards. This research studied the debris flow initiation in the Yindongzi gully in Dujiangyan City, Sichuan province, China with scaled-down model experiments. We set rainfall intensity and slope angle as dominating parameters and carried out 20 scaled-down model tests under artificial rainfall conditions. The experiments set four slope angles(32°, 34°, 37°, 42°) and five rainfall intensities(60 mm/h, 90 mm/h, 120 mm/h, 150 mm/h, and 180 mm/h) treatments. The characteristic variables in the experiments, such as, rainfall duration, pore water pressure, moisture content, surface inclination, and volume were monitored. The experimental results revealed the failure mode of loose slope material and the process of slope debris flow initiation, as well as the relationship between the surface deformation and the physical parameters of experimental model. A traditional rainfall intensity-duration early warning model(I-D model) was firstly established by using a mathematical regression analysis, and it was then improved into ISD model and ISM model(Here, I is rainfall Intensity, S is Slope angle, D is rainfall Duration, and M is Moisture content). The warning model can provide reliable early warning of slope debris flow initiation.

关键词： Slope debris flow Artificial rainfallmodel Early warning model model experiment