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101.
102.
以上瑞高速公路怀新段第8合同段青山冲隧道为工程实例,针对左线出口端洞口浅埋偏压情况,为了节约工程投资,实施了反压回填的处治方案,采用数值模拟分析及现场监控量测数据分析了偏压隧道支护结构的受力状态和稳定性,可供类似工程参考。 相似文献
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采用二维弹塑性数值计算方法,对小净距隧道拱顶位移、水平收敛进行数值模拟计算,研究围岩级别、净距、开挖方法对隧道变形的影响,揭示小净距隧道洞周变形特征。研究结论可为小净距隧道的设计、施工提供一定的指导。 相似文献
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为了探究含气率对多相混输泵内气液两相分布规律的影响,本文基于标准的k-ε湍流模型和时均N-S方程,对不同含气率下混输泵内的流态进行数值计算,分析了混输泵内不同位置处的气液两相分布规律。结果表明:不同压缩级动叶轮进口截面到出口截面的气相体积分数从轮毂至轮缘逐渐变小,同时叶轮靠近轮毂处、轮毂至轮缘中间位置处以及轮缘处的最大气体体积分数位置将随着含气率的增加而增加。另外在离心力的作用下混输泵动叶轮内越靠近轮缘液相越集中,越靠近轮毂气相越集中。此研究结果为提高多相混输泵的混输性能和运行效率提供了参考。 相似文献
107.
Subsea pipelines buried in the seabed may undergo large lateral displacement under environmental, operational, and accidental loads at different interaction rates and hence different drainage conditions. The undrained shear strength is commonly used in practice to assess the pipe-soil interaction assuming a sufficiently high displacement rate. This approach neglects consolidation effects and the rate-dependent response of the soil and may significantly underestimates the lateral resistance for a pipeline moving slowly relative to the ground. In this study, a coupled large deformation finite element (LDFE) framework is developed via a remeshing and interpolation technique with small strain (RITSS). A Modified Cam-Clay (MCC) model with efficient numerical integration is used. The proposed coupled LDFE framework is verified against selected physical model tests. Effects of the interaction rate and hence drainage condition on the p-y curve, excess pore pressure generation and dissipation, and failure mechanisms are discussed. An empirical relationship between the ultimate resistance and the normalized velocity of the pipe (denoting the drainage condition) is proposed, which may be applied for the integrity and safety analysis of buried pipes in landslide or fault-crossing regions. 相似文献
108.
层状岩体的力学特征和数值模拟方法研究 总被引:4,自引:0,他引:4
层状岩体由于具有层状结构,不仅变形和强度性质有异于一般的岩体,岩体的破坏方式及机理也具有明显的特点。作者在前人研究的基础上,结合自己对该问题的研究,全面总结了倾斜层状岩体的力学特征和数值模拟方法,并对各种模拟方法的优缺点进行了比较。 相似文献
109.
Parametrical studies based on numerical simulations were carried out for very steep regular waves to assess possible improvements
in the state-of-the art numerical modelling of the control and capsizing behaviour of ships in following and quartering seas.
A nonlinear 6-DOF numerical model has been developed with the inclusion of frequency-dependent terms, the so called memory
effects, and a flexible axis system that allows straightforward combination of seakeeping and manoeuvring models while accounting
for extreme motions. The previously undertaken validation analyses using extensive model test data provided qualitatively
good agreement, whereas the comparison with numerical models without coupling of the vertical motions and frequency-dependent
hydrodynamic terms embodied in radiation forces identified improvements in the accuracy. However, to broaden the assessment
of the numerical model, further parametrical numerical analyses were carried out using two ships, which had previously been
tested in the validation analyses, for various operational and environmental conditions. These parameters were changed in
accordance with the recommendations from international organisations and experience from model tests to realise and avoid
dangerous conditions that often result in capsizing, such as broaching associated with surf riding and low-cycle resonance.
As a result of the parametric analysis, we discuss the sensitivity of the improvements in the numerical model for various
critical operational and design parameters and its possible use to provide a link between the ship's behavior and these parameters. 相似文献
110.