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Study on the tunnel shape and soil-lining interaction influencing the lining behavior under seismic loading
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作者 Van Vi Pham Ngoc Anh Do +2 位作者 Piotr Osinski Ngoc Thai Do Daniel Dias 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第4期845-862,共18页
The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil properties.The individual behavior of circular,r... The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil properties.The individual behavior of circular,rectangular,and sub-rectangular tunnels subjected to seismic loadings has already been studied in the literature.In the present research,two case scenarios of circular,rectangular tunnels and four sub-rectangular shaped tunnels,with similar cross-section areas,were adopted to perform a comprehensive numerical investigation.The purpose of the study was to determine the mechanical behavior of tunnels of different shapes,depending upon seismic conditions.Analyses were performed by considering the influence of soil-lining interaction,soil parameters,and lining thickness,as well as lining rigidity.Computations were performed for no-slip and full-slip conditions.The results indicate that the tunnel shape design is of great importance when regarding the mechanical behavior of the surrounding soil.This concerns no-slip as well as full-slip soil-lining interaction,especially when the lining is subjected to seismic loading.Moreover,it is shown that changes in incremental bending moments for circular,rectangular and sub-rectangular tunnels that depend upon the soil-lining interaction conditions differ significantly. 展开更多
关键词 tunnel shape soil-lining interaction seismic loading internal forces numerical analysis
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Optimization of ambipolar current and analog/RF performance for T-shaped tunnel field-effect transistor with gate dielectric spacer
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作者 Ru Han Hai-Chao Zhang +1 位作者 Dang-Hui Wang Cui Li 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第1期656-662,共7页
A new T-shaped tunnel field-effect transistor(TTFET) with gate dielectric spacer(GDS) structure is proposed in this paper. To further studied the effects of GDS structure on the TTFET, detailed device characteristics ... A new T-shaped tunnel field-effect transistor(TTFET) with gate dielectric spacer(GDS) structure is proposed in this paper. To further studied the effects of GDS structure on the TTFET, detailed device characteristics such as current-voltage relationships, energy band diagrams, band-to-band tunneling(BTBT) rate and the magnitude of the electric field are investigated by using TCAD simulation. It is found that compared with conventional TTFET and TTFET with gate-drain overlap(GDO) structure, GDS-TTFET not only has the minimum ambipolar current but also can suppress the ambipolar current under a more extensive bias range. Furthermore, the analog/RF performances of GDS-TTFET are also investigated in terms of transconductance, gate-source capacitance, gate-drain capacitance, cutoff frequency, and gain bandwidth production. By inserting a low-κ spacer layer between the gate electrode and the gate dielectric, the GDS structure can effectively reduce parasitic capacitances between the gate and the source/drain, which leads to better performance in term of cutoff frequency and gain bandwidth production. Finally, the thickness of the gate dielectric spacer is optimized for better ambipolar current suppression and improved analog/RF performance. 展开更多
关键词 tunneling field effect TRANSISTOR T-shaped tunnel FIELD-EFFECT TRANSISTOR gate dielectric SPACER ambipolar current analog/RF performance
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Evolution of crescent-shaped sand dune under the influence of injected sand flux:scaling law and wind tunnel experiment
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作者 ZHANG Yang WANG Yuan +1 位作者 ZHOU Xiaosi YANG Bin 《Journal of Arid Land》 SCIE CSCD 2017年第2期270-277,共8页
This paper studies the evolution of crescent-shaped dune under the influence of injected flux. A scaling law and a wind tunnel experiment are carried out for comparison. The experiment incorporates a novel image proce... This paper studies the evolution of crescent-shaped dune under the influence of injected flux. A scaling law and a wind tunnel experiment are carried out for comparison. The experiment incorporates a novel image processing algorithm to recover the evolutionary process. The theoretical and experimental results agree well in the middle stage of dune evolution, but deviate from each other in the initial and final stages, suggesting that the crescent-shaped dune evolution is intrinsically scale-variant and that the crescent shape breaks down under unsaturated condition. 展开更多
关键词 crescent-shaped sand dune scale-invariant model wind tunnel experiment image processing
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Mechanical Behavior and Shape Optimization of Lining Structure for Subsea Tunnel Excavated in Weathered Slot 被引量:2
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作者 李鹏飞 周晓军 《China Ocean Engineering》 SCIE EI CSCD 2015年第6期875-890,共16页
Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the c... Subsea tunnel lining structures should be designed to sustain the loads transmitted from surrounding ground and groundwater during excavation. Extremely high pore-water pressure reduces the effective strength of the country rock that surrounds a tunnel, thereby lowering the arching effect and stratum stability of the structure. In this paper, the mechanical behavior and shape optimization of the lining structure for the Xiang'an tunnel excavated in weathered slots are examined. Eight cross sections with different geometric parameters are adopted to study the mechanical behavior and shape optimization of the lining structure. The hyperstatic reaction method is used through finite element analysis software ANSYS. The mechanical behavior of the lining structure is evidently affected by the geometric parameters of crosssectional shape. The minimum safety factor of the lining structure elements is set to be the objective function. The efficient tunnel shape to maximize the minimum safety factor is identified. The minimum safety factor increases significantly after optimization. The optimized cross section significantly improves the mechanical characteristics of the lining structure and effectively reduces its deformation. Force analyses of optimization process and program are conducted parametrically so that the method can be applied to the optimization design of other similar structures. The results obtained from this study enhance our understanding of the mechanical behavior of the lining structure for subsea tunnels. These results are also beneficial to the optimal design of lining structures in general. 展开更多
关键词 subsea tunnel lining structure shape optimization safety factor hyperstatic reaction method
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3D Ice Shape Description Method Based on BLSOM Neural Network
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作者 ZHU Bailiu ZUO Chenglin 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第S01期70-80,共11页
When checking the ice shape calculation software,its accuracy is judged based on the proximity between the calculated ice shape and the typical test ice shape.Therefore,determining the typical test ice shape becomes t... When checking the ice shape calculation software,its accuracy is judged based on the proximity between the calculated ice shape and the typical test ice shape.Therefore,determining the typical test ice shape becomes the key task of the icing wind tunnel tests.In the icing wind tunnel test of the tail wing model of a large amphibious aircraft,in order to obtain accurate typical test ice shape,the Romer Absolute Scanner is used to obtain the 3D point cloud data of the ice shape on the tail wing model.Then,the batch-learning self-organizing map(BLSOM)neural network is used to obtain the 2D average ice shape along the model direction based on the 3D point cloud data of the ice shape,while its tolerance band is calculated using the probabilistic statistical method.The results show that the combination of 2D average ice shape and its tolerance band can represent the 3D characteristics of the test ice shape effectively,which can be used as the typical test ice shape for comparative analysis with the calculated ice shape. 展开更多
关键词 icing wind tunnel test ice shape batch-learning self-organizing map neural network 3D point cloud
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Mechanical properties and influence mechanism of confined concrete arches in high-stress tunnels 被引量:10
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作者 Bei Jiang Zhongxin Xin +4 位作者 Xiufeng Zhang Yusong Deng Mingzi Wang Shidong Li Wentao Ren 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第7期829-841,共13页
Deep underground projects(e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient,whic... Deep underground projects(e.g., coal mines), are often faced with complex conditions such as high stress and extremely soft rock. The strength and rigidity of the traditional support system are often insufficient,which makes it difficult to meet the requirements of ground control under complex conditions. As a new support form with high strength and rigidity, the confined concrete arch plays an important role in controlling the rock deformation under complex conditions. The section shape of the tunnel has an important impact on the mechanical properties and design of the support system. However, studies on the mechanical properties and influence mechanism of the new confined concrete arch are rarely reported. To this end, the mechanical properties of traditional U-shaped steel and new confined concrete arches are compared and comparative tests on arches of circular and straight-leg semicircular shapes in deep tunnels are conducted. A large mechanical testing system for underground engineering support structure is developed. The mechanical properties and influence mechanism of confined concrete arches with different section shapes under different loading modes and cross-section parameters are systematically studied. Test results show that the bearing capacity of the confined concrete arch is 2.10 times that of the U-shaped steel arch, and the bearing capacity of the circular confined concrete arch is 2.27 times that of the straight-leg semicircular arch. Among the various influencing factors and their engineering parameters,the lateral stress coefficient has the greatest impact on the bearing capacity of the confined concrete arch,followed by the steel pipe wall thickness, steel strength, and core concrete strength. Subsequently, the economic index of bearing capacity and cost is established, and the optimization design method for the confined concrete arch is proposed. Finally, this design method is applied to a high-stress tunnel under complex conditions, and the deformation of the surrounding rock is effectively controlled. 展开更多
关键词 High-stress tunnel Confined concrete arch Section shape Mechanical properties Design method
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Determination of minimum overburden depth for underwater shield tunnel in sands:Comparison between circular and rectangular tunnels 被引量:4
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作者 Weixin Sun Fucheng Han +4 位作者 Hanlong Liu Wengang Zhang Yanmei Zhang Weijia Su Songlin Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第7期1671-1686,共16页
With the development of global urbanization,the utilization of underground space is more critical and attractive for civil purposes.Various shapes of shield tunnels have been gradually proposed to cope with different ... With the development of global urbanization,the utilization of underground space is more critical and attractive for civil purposes.Various shapes of shield tunnels have been gradually proposed to cope with different geological conditions and service purposes of underground structures.Generally,reducing the burial depth of shield tunnel is conducive to construction and cost saving.However,extremely small overburden depth cannot provide sufficient uplift resistance to maintain the stability and serviceability of the tunnel.To this end,this paper firstly reviewed the status of deriving the minimum sand over-burden depth of circular shield tunnel using mechanical equilibrium(ME)method.It revealed that the estimated depth is rather conservative.Then,the uplift resistance mechanism of both circular and rectangular tunnels was deduced theoretically and verified with the model tests.The theoretical uplift resistance is consistent with the experimental values,indicating the feasibility of the proposed equations.Furthermore,the determination of the minimum soil overburden depth of rectangular shield tunnel under various working conditions was presented through integrated ME method,which can provide more reasonable estimations of suggested tunnel burial depth for practical construction.Additionally,optimizations were made for calculating the uplift resistance,and the soil thickness providing uplift resistance is suggested to be adjusted according to the testing results.The results can provide reference for the design and construction of various shapes of shield tunnels in urban underground space exploitation. 展开更多
关键词 Minimum overburden depth Uplift resistance mechanism Shield tunnel shape tunnel anti-floating
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The lining responses for shallow mountain tunnels subjected to frost heaving 被引量:1
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作者 LING Xian-zhang YU Yuan +2 位作者 TANG Liang GENG Lin HAN Xiao 《Journal of Mountain Science》 SCIE CSCD 2022年第2期529-546,共18页
Mountain tunnels in cold regions are vulnerable to adverse effects of freezing action.Thus,it is necessary to identify the lining responses of shallow mountain tunnels subjected to freezing action.To quantify the infl... Mountain tunnels in cold regions are vulnerable to adverse effects of freezing action.Thus,it is necessary to identify the lining responses of shallow mountain tunnels subjected to freezing action.To quantify the influence of freezing action and key design parameters(such as cross-sectional shape;lining thickness;and waterproof measures)on the lining response,a thermal-hydro-mechanical coupled finite element(FE)model is established and verified.Then,specific consideration is given to the lining internal force and resulting axial stresses.And the influences of the cross-sectional shape,concrete parameters,and waterproof measures on the lining responses are investigated.Generally,the rectangular tunnel has the worst security;the circular tunnel is the safest.On the other hand,when the thermal conductivity is less than 2.2[W/(m·K)],a greater thermal conductivity will cause a greater risk of damage to the lining.Moreover,the drainage plate can reduce the value of minimum axial stresses,whether frozen or not,even eliminating the tensiondamaged area.Overall,this study helps to estimate the lining responses and prevent frost damages for shallow mountain tunnels during freezing period. 展开更多
关键词 Coupled thermal-hydro-mechanical model Mountain tunnel in the cold region Lining responses Cross-sectional shape Freezing action
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Tunnel flexibility effect on the ground surface acceleration response 被引量:8
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作者 Mohammad Hassan Baziar asoud Rabeti Moghadam +1 位作者 Yun Wook Choo Dong-Soo Kim 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第3期457-476,共20页
Flexibility of underground structures relative to the surrounding medium, referred to as the flexibility ratio, is an important factor that influences their dynamic interaction. This study investigates the flexibility... Flexibility of underground structures relative to the surrounding medium, referred to as the flexibility ratio, is an important factor that influences their dynamic interaction. This study investigates the flexibility effect of a box-shaped subway tunnel, resting directly on bedrock, on the ground surface acceleration response using a numerical model verified against dynamic centrifuge test results. A comparison of the ground surface acceleration response for tunnel models with different flexibility ratios revealed that the tunnels with different flexibility ratios influence the acceleration response at the ground surface in different ways. Tunnels with lower flexibility ratios have higher acceleration responses at short periods, whereas tunnels with higher flexibility ratios have higher acceleration responses at longer periods. The effect of the flexibility ratio on ground surface acceleration is more prominent in the high range of frequencies. Furthermore, as the flexibility ratio of the tunnel system increases, the acceleration response moves away from the free field response and shifts towards the longer periods. Therefore, the flexibility ratio of the underground tunnels influences the peak ground acceleration (PGA) at the ground surface, and may need to be considered in the seismic zonation of urban areas. 展开更多
关键词 box-shaped tunnel flexibility ratio acceleration response ground surface centrifuge modeling numericalsimulation
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Research on the optimal design of spillway tunnel
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作者 ZHANG Yankui LIU Xiaolian 《International English Education Research》 2016年第4期86-88,共3页
In order to meet the needs of various tasks of water conservancy project, tunnel excavation under the ground, called hydraulic tunnel. Hydraulic tunnel according to the functions of flood discharge, water diversion, i... In order to meet the needs of various tasks of water conservancy project, tunnel excavation under the ground, called hydraulic tunnel. Hydraulic tunnel according to the functions of flood discharge, water diversion, irrigation, water supply, and the construction diversion tunnel of desilting emptying. Nowadays, water conservancy project on flood discharge runnel design requirements more and more high, so the factors taken into account the amount of spillway tunnel engineering, engineering cost, structure design and other factors to evaluate nature of the spillway tunnel is very important. Therefore, in actual construction, of spillway tunnel of optimization design, whether from the economic point of view, or from the point of view of safety and applicability are necessary. This article mainly from the overall layout of flood discharge tunnel, structure design and so on, and then discuss the optimization scheme. 展开更多
关键词 Spillway tunnel General layout design shape optimiTation Energy dissipation
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周边孔聚能装置间隔装药在光面爆破中的应用研究 被引量:1
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作者 王清标 王涛 +5 位作者 田成林 孙永 魏祥 李中辉 王旭 李悦 《爆破》 CSCD 北大核心 2024年第1期77-84,共8页
隧道光面爆破工程的周边孔需要采用间隔装药方式,而大部分间隔装药方式采用“导爆索+雷管”联合起爆技术,此技术具有一定的局限性且经常发生拒爆现象。如何在保证隧道掘进效率的前提下提高光面爆破效果成为目前亟待解决的难题,从现场试... 隧道光面爆破工程的周边孔需要采用间隔装药方式,而大部分间隔装药方式采用“导爆索+雷管”联合起爆技术,此技术具有一定的局限性且经常发生拒爆现象。如何在保证隧道掘进效率的前提下提高光面爆破效果成为目前亟待解决的难题,从现场试验方面开展相关研究,提出“聚能装置+数码电子雷管”新型联合起爆技术,将其应用于高原某隧道,通过与原始的“导爆索+数码电子雷管”联合起爆技术的爆破后效果进行对比分析。实验结果表明:对比原始技术,新技术炸药单耗降低了0.2 kg/m^(3),半孔留痕率提高了5%,平均装药时间由原来的1.3 h降为1.0 h,稳定循环进尺的同时极大降低了耗材费用,提高了隧道光面爆破效果。 展开更多
关键词 隧道开挖 光面爆破 间隔装药 联合起爆技术 聚能装置
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Generation and Shaping of Soliton-Like Pulses along Resonant Tunneling Diodes NMOS Varactors Lattice
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作者 Yerima Klofai Bernard Z.Essimbi 《Journal of Modern Physics》 2013年第8期1099-1104,共6页
The characteristics of N-type accumulation-mode MOS (NMOS) varactors line periodically loaded with resonant tunneling diodes (RTDs) are used for soliton-like pulses generation and shaping. The problem of wide pulse br... The characteristics of N-type accumulation-mode MOS (NMOS) varactors line periodically loaded with resonant tunneling diodes (RTDs) are used for soliton-like pulses generation and shaping. The problem of wide pulse breaking up into multiple pulses rather than a single is solved. Applying perturbative analysis, we show that the dynamics of the nonlinear transmission line (NLTL) is reduced to expanded Korteweg-de Vries (KdV) equation. Moreover, numerical integration of nonlinear differential and difference equations that result from the mathematical analysis of the line is discussed. As results, NLTL can simultaneously sharpen both leading and trailing of pulse edges and one could obtain a rising and sharpening step pulse. 展开更多
关键词 Accumulation-Mode MOS Soliton-Like Pulse Generation and Shaping Resonant tunneling Diode Active Nonlinear Electrical Lattice Expanded KdV Equation
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沈阳恒隆市府广场超高层塔楼风荷载分析研究 被引量:1
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作者 陈勇 陈鹏 金钊 《建筑结构》 北大核心 2024年第11期149-154,共6页
为了确定高度350.6m沈阳恒隆市府广场塔楼结构设计的风荷载,采用刚性风洞试验与风洞数值模拟相结合的方法分析塔楼的风荷载,风洞试验研究给出楼层剪力与扭矩及风致加速度。采用四种湍流模型进行风洞数值模拟,分析建筑平均风压系数、体... 为了确定高度350.6m沈阳恒隆市府广场塔楼结构设计的风荷载,采用刚性风洞试验与风洞数值模拟相结合的方法分析塔楼的风荷载,风洞试验研究给出楼层剪力与扭矩及风致加速度。采用四种湍流模型进行风洞数值模拟,分析建筑平均风压系数、体型系数、基底剪力及倾覆力矩,并与风洞试验进行比较,得出适用于超高层建筑风洞模拟的湍流分析模型,利用该分析模型的数值风洞模拟技术,分析塔楼13个风向角的风压系数、体型系数和基底剪力,为结构风荷载取值提供依据。研究结果表明:相比于《建筑结构荷载规范》(GB 50009—2012)对近似矩形平面建筑物的体型系数的规定,RSM模型迎风面0.83、背风面-0.56,与规范矩形截面迎风面0.8、背风面-0.6最为接近;RSM模型与试验吻合最好;选取RSM模型来分析超高层等大型复杂结构风荷载,能够得到较为准确的结果。 展开更多
关键词 超高层塔楼 刚性风洞试验 数值模拟 风压系数 体型系数 湍流模型
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鼓形建筑的气动荷载特性及其干扰效应研究
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作者 陈元坤 李霆 +3 位作者 卢亦焱 宋杰 李宏胜 陈晓强 《工程力学》 EI CSCD 北大核心 2024年第8期68-79,共12页
通过多点同步测压风洞试验,系统分析了圆角率25%和50%的单个鼓形建筑表面风压、风荷载功率谱及整体力系数,并研究了两个鼓形建筑并排和串列布置时,不同间距和圆角率的两鼓形建筑的干扰效应。结果表明,鼓形建筑在降低圆角处平均风压的同... 通过多点同步测压风洞试验,系统分析了圆角率25%和50%的单个鼓形建筑表面风压、风荷载功率谱及整体力系数,并研究了两个鼓形建筑并排和串列布置时,不同间距和圆角率的两鼓形建筑的干扰效应。结果表明,鼓形建筑在降低圆角处平均风压的同时会使脉动风压峰值的位置向迎风端移动,且增大其峰值,造成圆角处较大的极值负压。鼓形建筑宽边迎风时横风向荷载Strouhal数较矩形建筑高,且随着圆角率增大而增大;窄边迎风时,鼓形建筑横风向荷载功率谱出现两个峰值,主峰值在fB/V_(h)=0.03附近,次级漩涡脱落形成的次峰值出现在fB/V_(h)=0.25。两个鼓形建筑并排布置时,鼓形建筑间的狭缝效应会大大增加两内侧的负压,尤其是对于圆角率50%的鼓形建筑。两建筑串列布置时,上游建筑的遮挡效应使下游迎风面的负压显著降低;由于受到上游建筑尾流的影响,下游建筑侧面迎风端的负压也大大低于单塔建筑。 展开更多
关键词 鼓形高层建筑 气动特性 干扰效应 风效应 风洞试验
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边箱式π型断面涡振性能及导流板措施参数研究
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作者 王峰 邢丰 +4 位作者 熊川 王佳盈 郑晓东 张久鹏 黄晓明 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第5期114-122,共9页
π型断面因构造简单与受力性能好,被广泛应用于桥梁建设中,但其抗风性能差,易产生涡激振动问题.本文以边箱式π型断面桥梁为研究对象,采用宽高比10∶1的π型断面刚体节段模型进行同步测振测压试验,并且通过计算流体力学方法加以对比验证... π型断面因构造简单与受力性能好,被广泛应用于桥梁建设中,但其抗风性能差,易产生涡激振动问题.本文以边箱式π型断面桥梁为研究对象,采用宽高比10∶1的π型断面刚体节段模型进行同步测振测压试验,并且通过计算流体力学方法加以对比验证,研究π型断面涡振性能与导流板抑振机理.试验结果表明:边箱式π型断面在0°、±3°风攻角下发生显著涡激振动,通过在断面两侧加设特定形式及尺寸参数的导流板措施可抑制断面竖弯及扭转涡振.其中,倒L型导流板措施气动优化效果显著,可有效消除涡振振幅,而水平导流板措施的抑振效果有限,相较于竖弯涡振,扭转涡振对于水平导流板尺寸参数更为敏感.通过对比数值模拟结果与表面气动压力分布,表明倒L型导流板措施能够优化断面气动外形,削弱断面上下表面旋涡脱落尺度和能量,同时降低断面所受的周期性气动力,从而有效抑制断面涡振. 展开更多
关键词 π型断面 涡激振动 风洞试验 导流板 风压
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低空封闭连廊的表面风压和整体体型系数
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作者 沈国辉 韩康辉 +2 位作者 刘若斐 余杭聪 林巍 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第5期123-131,共9页
采用刚性模型测压风洞试验研究低空封闭连廊的风压分布和整体体型系数,分析连廊4个表面测点的体型系数和非高斯分布特性,研究连廊整体体型系数随风向角和连廊长度的变化,给出低空封闭连廊的正迎风整体体型系数和角度风分配系数,基于极... 采用刚性模型测压风洞试验研究低空封闭连廊的风压分布和整体体型系数,分析连廊4个表面测点的体型系数和非高斯分布特性,研究连廊整体体型系数随风向角和连廊长度的变化,给出低空封闭连廊的正迎风整体体型系数和角度风分配系数,基于极值分析方法给出连廊的全风向极值风压系数,最后给出连廊抗风设计的建议值.研究表明,低空封闭连廊在正吹情况下背风面的体型系数约为-1.04~-0.86,绝对值均大于规范中方柱的-0.6,导致连廊的整体体型系数大于规范中方柱的1.4,30 m长低空封闭连廊的整体阻力系数为1.61;正吹情况下连廊中间截面的整体体型系数大于其他截面,正吹风向角的整体体型系数大于其他风向角,连廊越长正迎风整体体型系数越大;在正吹情况下,连廊迎风面风压主要为高斯分布,其他表面主要为非高斯分布;给出正迎风整体体型系数和角度风分配系数以用于低空封闭连廊主体结构的抗风设计. 展开更多
关键词 连廊 风洞试验 体型系数 非高斯分布 极值风压系数
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近地面大长宽比跟踪式光伏阵列风洞试验研究
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作者 贺佳 廖教宇 +3 位作者 张肖雄 胡美妃 张芮洋 陈政清 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第11期43-52,共10页
为明确近地面风场对跟踪式光伏结构风荷载取值的影响,本文基于风洞试验和计算流体力学(CFD)模拟对单排光伏组件的倾角、风向角、离地高度展开分析,并在此基础上研究了多排光伏阵列在不同风向角下,其遮挡效应对体型系数取值的影响.结果表... 为明确近地面风场对跟踪式光伏结构风荷载取值的影响,本文基于风洞试验和计算流体力学(CFD)模拟对单排光伏组件的倾角、风向角、离地高度展开分析,并在此基础上研究了多排光伏阵列在不同风向角下,其遮挡效应对体型系数取值的影响.结果表明:单排光伏组件的表面风压符合梯形分布方式;多排光伏阵列中上游组件对下游的遮挡程度会随倾角的增大而增长,且后排光伏组件体型系数随着前排遮挡的增多逐渐趋于稳定;离地高度对光伏组件及阵列的体型系数存在一定的影响. 展开更多
关键词 光伏阵列 风洞试验 CFD模拟 体型系数 结构荷载
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公路隧道箱型预制仰拱变形破坏的模型试验研究
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作者 王迎超 徐杭 +3 位作者 郝英 周鑫 刘泾堂 李元海 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2024年第7期1417-1426,共10页
基于自主设计的新型箱型预制仰拱结构,采用室内物理模型试验,结合数字照相量测技术,研究该箱型预制仰拱的力学特性及破坏模式,通过数值模拟研究实际工况中衬砌与仰拱共同作用的受力规律.结果表明:竖向荷载作用下产生的拉张效应是预制仰... 基于自主设计的新型箱型预制仰拱结构,采用室内物理模型试验,结合数字照相量测技术,研究该箱型预制仰拱的力学特性及破坏模式,通过数值模拟研究实际工况中衬砌与仰拱共同作用的受力规律.结果表明:竖向荷载作用下产生的拉张效应是预制仰拱裂纹产生及发展的主要原因,水平压力对预制仰拱的裂纹发展作用不明显.预制块接缝处以及各个预制块中柱转角处是预制仰拱结构的最薄弱部位,接缝处和转角处影响预制仰拱结构的安全.预制仰拱位移变化关于中轴部位呈对称分布,位移由大到小依次为中间预制块、左1预制块、左2预制块、左3预制块.箱型预制仰拱破坏可以分为加载压密、弹塑性变形和塑性破坏3个阶段.当仰拱与衬砌共同作用时,仰拱的上部主要承受拉应力,仰拱的下部主要承受压应力.试验结果表明,所设计仰拱结构具有良好的受力性能. 展开更多
关键词 公路隧道 箱型预制仰拱 室内模型试验 仰拱裂隙 仰拱接头
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槽形钢箱梁涡振性能及抑振措施试验研究
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作者 封周权 戴金元 +1 位作者 陈诗璇 华旭刚 《世界桥梁》 北大核心 2024年第3期83-89,共7页
为提高槽形钢箱梁桥的抗风性能,对槽形钢箱梁的涡振性能及抑振措施进行试验研究。以某人行景观桥槽形钢箱梁为背景,通过主梁节段模型风洞试验,研究+3°、0°、-3°风攻角下均匀流与紊流风场中槽形钢箱梁的涡振性能,分析交... 为提高槽形钢箱梁桥的抗风性能,对槽形钢箱梁的涡振性能及抑振措施进行试验研究。以某人行景观桥槽形钢箱梁为背景,通过主梁节段模型风洞试验,研究+3°、0°、-3°风攻角下均匀流与紊流风场中槽形钢箱梁的涡振性能,分析交替封闭栏杆、将栏杆楔形扶手改为圆形扶手、提高阻尼比等措施的抑振效果。结果表明:原槽形钢箱梁断面涡振性能不满足规范要求,均匀流风场中,3个风攻角下均出现了超限的竖弯涡振,+3°和-3°风攻角下出现了不同程度的扭转涡振,最不利风攻角为-3°;紊流风场中,最不利风攻角下原断面竖弯涡振振幅降低了23%,未见明显扭转涡振;楔形扶手栏杆交替封闭使结构竖弯涡振振幅增大,主梁涡振性能降低;单独改变栏杆扶手形状为圆形对主梁涡振性能影响不大,在此基础上交替封闭栏杆能够有效抑制主梁涡振;提高结构阻尼比能有效抑制主梁涡振,阻尼比为7‰时,主梁竖弯涡振振幅可降至规范限值的一半左右。 展开更多
关键词 人行桥 槽形钢箱梁 风致振动 涡振性能 抑振措施 扶手形状 阻尼比 风洞试验
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抽蓄电站无压隧洞交叉区体型优化试验研究
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作者 田静 顾长宽 +1 位作者 郭汉驰 薛海 《水电能源科学》 北大核心 2024年第10期115-117,38,共4页
交叉无压隧洞交汇区域水流的水力特性复杂,无压隧洞交叉区体型及交汇口水流水力特性的研究对确保水利枢纽的安全运行具有重要的工程意义。基于物理模型试验,对某抽水蓄能电站下水库高落差泄洪排沙洞和放空洞交叉区体型进行优化,最终确... 交叉无压隧洞交汇区域水流的水力特性复杂,无压隧洞交叉区体型及交汇口水流水力特性的研究对确保水利枢纽的安全运行具有重要的工程意义。基于物理模型试验,对某抽水蓄能电站下水库高落差泄洪排沙洞和放空洞交叉区体型进行优化,最终确定圆弧连接+交叉角21°的交叉区体型。对比分析圆弧连接+交叉角21°的交叉区优化体型下特征试验工况的水力特性。结果表明,6种特征试验工况下,泄洪排沙洞和放空洞交叉口及下游均为急流,明流泄洪且流态较稳定,均在交汇口下游右边直墙处形成最大水深,水深低于直墙高度,满足水面线不宜超过直墙范围的要求。 展开更多
关键词 交叉无压隧洞 体型优化 交汇水流 抽水蓄能电站 模型试验
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