岩基上坞式船闸结构底板预留宽缝施工方法效果分析

坞式结构是船闸闸首或闸室常采用的一种结构形式,但采用这种结构形式的船闸底板容易出现裂缝.株洲船闸工程为防止裂缝产生,拟定了底板预留宽缝的施工方法.结合非线性有限元仿真分析方法,考虑重力、温度等荷载,计算分析了船闸结构底板预留宽缝施工方法的效果.计算结果对类似工程的设计和施工具有一定的参考价值.     

基于分层地基模型的闸首分缝底板计算方法

为研究深基坑开挖对地基沉降和分缝底板内力的影响，分析地基应力在船闸施工期、运行期的变化全过程，探讨土体回弹模量和压缩模量的关系，基于分层总和法，建立反映地基应力历史影响的非线性分层地基模型。结合龙洲垸船闸实例，探讨自重折扣法、并列铰接空间地基梁法在分缝底板计算中的应用。回弹模量比的影响分析表明，在合缝至完建期，底板下地基刚度呈现中部大、两侧小的特征，若不考虑再压缩模量的影响，则计算的底板沉降偏大、负弯矩偏小。通过多种合缝方案对比分析，建议合缝前边墩尽可能一次浇筑到顶，必要时再通过回填土调整底板内力。施工时应加强沉降与应力监测，应用基于分层地基模型的反分析方法，及时验证设计，动态调整施工方案，以确保底板弯矩在可控范围内。     

坞式船闸底板受力演化特性及分缝防裂方法效果

为了进一步分析坞式船闸底板开裂原因,采用多场耦合分析方法建立了有限元模型,模拟常规施工过程,分析底板受力时变演化过程和特点,指出常规设计方法作为一种瞬时分析方法不能较好考虑时间因素。同时,对改变底板力学演化特性的预留宽缝施工方法进行了探讨,分析了其改善底板受力的效果,指出其效果良好,能减少底板的拉应力,有效防止底板表面开裂,建议在大型船闸工程建设中多加采用。     

粘弹性半空间地基上板在动荷下的挠度计算

本文根据弹性理论和粘弹性理论之间的对应法则,推导了粘弹性地基上板在静荷载作用下的挠度计算公式。为使路面计算荷载模型较好地反映实际情况,本文在上述基础上又推导了粘弹性地基上板在移动荷载作用下的挠度计算公式。该公式为今后刚性路面设计由动荷载代替静荷载、粘弹性地基代替弹性地基提供了理论依据。     

软基上结构仿真计算方法及其应用

根据半无限大地基弹性沉陷公式,利用线粘弹性－弹性相应原理及Ｌａｐｌａｃｅ变换等数学工具,导出了Ｋｅｌｖｉｎ型和三参量粘弹性地基沉陷公式。用空间八结点徐变等参单元离散上部结构,地基沉陷采用粘弹性理论解,提出了对软基上结构进行仿真计算的半解析计算方法,并编制了相应的计算程序,实例计算表明,仿真算法能很好地模拟整个工程从开挖施工到正常运行的全过程。     

软土地基上超长底板节制闸沉降及应力分析

软土地基上的水闸可能产生较大的沉降,对于新型超长底板水闸,还存在局部受拉破坏等隐患.本文结合典型工程实例,基于有限单元法及土力学,计算分析底板分缝与不分缝两种方案下闸室中心的沉降及水闸底板的应力情况,同时通过预应力钢筋的应用,探讨底板空箱结构优化可行性.结果表明:空箱底板拉应力数值比较大,底板空箱结构受力不好,施加预应力可以有效缓解底板上层的拉应力,但会存在预应力吨位过大等问题.可以对该类型水闸的闸室结构型式设计提供参考依据.     

动载荷作用下无限长FGM梁在分数阶粘弹性地基上的精确解

基于分数阶微分Zener型粘弹性地基模型,建立动载荷作用下无限长FGM梁在分数阶粘弹性地基上的运动控制微分方程。利用傅立叶和拉普拉斯变换将控制微分方程简化为代数方程,首先在频率域内得到解答,然后利用傅立叶和拉普拉斯逆变换以及卷积定理将解答再转换回时间域内,得到粘弹性地基上FGM梁的挠度、速度、加速度、弯矩和剪力响应的精确解。最后,计算了冲击荷载作用下弹性地基FGM梁的动态响应,给出了x =0处梁的垂直速度和弯矩的响应曲线,其形状特征和均匀材料梁相同,且材料梯度指标p对结果的影响较小。     

窄缝挑坎上最大压力的计算

本文通过试验,首先描述了窄缝挑流的水舌流态;其次根据对一般曲面上水流运动特性的分析,提出了水平底板、挑角为零度的窄缝挑坎上最大压力的计算公式。计算结果与试验结果吻合较好。最后,还对窄缝挑坎底板及侧墙上压力分布的计算进行了探讨。     

双参数地基模型下预应力闸室底板计算方法研究

闸室底板是闸室结构容易开裂的部位,目前国内外对预应力闸室底板计算方法的研究较少。为了更好的研究预应力闸室底板变形以及受力特征,该文在双参数地基模型下对闸室底板施加预应力,通过构造三次样条插值函数把预应力荷载转化为等效节点荷载,用计算普通弹性地基梁的方法计算预应力闸室底板。计算结果表明,给闸室底板布置合理的预应力形式能够达到减小地基不均匀沉降和闸室底板的内力的目的,对预应力闸室结构的设计具有指导意义。     

Kelvin地基上悬臂输流管道的动力特性分析

在弹性地基上弹性输流管道研究的基础上，用改进的有限差分法术解了Kelvin—Voigt模型粘弹性地基上悬臂输流管道的动力特性和稳定性问题。计算结果表明，地基的无量纲松弛时间H、管道与地基的弹性模量比α以及质量比β对管道的动力特性和稳定性有着重要的影响。一般来说，颤振临界流速随表H和α的增大而增大。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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