沙河集水库坝身裂缝及塌坡原因分析

沙河集水库1987年及1991年汛期两次发生坝顶裂缝和下游坝坡塌坡,严重威胁下游安全。根据坝坡稳定计算、应力应变分析及筑坝土料力学特性分析,坝坡整体稳定和局部稳定均满足规范要求,坝顶裂缝及下游坝坡塌坡主要是由于坝身第五期工程填筑质量差,遇水湿陷、坝顶和下游坝肩拉应力及潜在的拉裂缝或拉松带、加上连续暴雨雨水入渗综合作用所致。     

考虑流固耦合的水位降落期坝坡稳定分析

水位降落期的土石坝坝坡稳定性是土石坝设计和除险加固设计中的重要内容之一,为了能够准确合理地分析水位降落期土石坝的坝坡稳定性,采用基于非饱和土流固耦合理论的有限元法对某病险水库进行了水位降落期的坝坡稳定分析,与传统的极限平衡法的计算结果进行了对比,同时分析了材料参数对坝坡稳定性的影响．结果表明基于非饱和土流固耦合理论的有限元法是一种方便合理的计算方法,计算出的孔隙水压力分布和坝坡稳定系数更加符合实际;材料的内摩擦角和粘聚力对坝坡稳定系数影响较大,泊松比影响相对较小,弹性模量几乎无影响．     

除险水库土坝渗流稳定计算分析

大坝坝基、坝体渗流稳定、渗流变形稳定及坝体、坝坡抗滑稳定计算分析是大坝稳定安全评价的一项基本的重要内容。本文通过对帕满水库除险加固前后大坝坝基、坝体、坝坡稳定计算比对分析,实现了大坝稳定定性与定量分析评价结合及防渗加固处理的措施的必要性。     

不同坡度的胶凝砂砾石百米级高坝的层间稳定性分析

采用ANSYS有限元软件,在层间界面上使用节点耦合方法,建立有限元模型,并采用ANSYS参数化命令流提取层间界面上的节点坐标、节点应力,计算不同坡度(M=0.5~0.8)的胶凝砂砾石百米级高坝的层间抗滑稳定系数,分析层间抗滑稳定系数的影响因素。结果表明:从工程量最小角度考虑,优选坝坡为M=0.7;单独增大摩擦系数、粘聚力时,层间上各节点的稳定系数均会增大,但摩擦系数的影响稍大;单独增大弹性模量时,靠近坝踵3/4的层间节点稳定系数均增大、靠近坝趾1/4的层间节点稳定系数均减少。     

基于ANSYS和JC法的高土石坝动力可靠度稳定性分析

土石坝在建成或拟建的大坝中占有大部分比重,坝坡的稳定性是土石坝工程设计的关键问题,而强震下的坝坡稳定性更是岩土领域中的热点问题.运用ANSYS软件对某一高土石坝边坡进行时程分析,结合可靠度指标计算方法JC法,通过迭代计算得到可靠度指标,进而求得动力可靠度安全系数及最小可靠度指标,其分析结果对高土石坝的动力稳定性分析有广泛的应用价值.     

基于ANSYS的尾矿坝渗流场的计算分析

坝坡浸润线是尾矿坝的生命线,它是直接影响坝体安全的一个非常重要的因素。本文选取典型断面借助通用有限元软件ANSYS进行渗流计算,确定不同干滩长度下浸润线的位置,并对计算结果进行分析,评价结构的安全状况,为尾矿库的安全生产与管理提供一定的科学依据。     

某尾矿坝稳定性分析

为保证尾矿库的安全生产,需对尾矿坝进行中期的系统稳定性评价.对尾矿坝进行二维稳定渗流分析来计算其浸润线,再对尾矿库坝体在三种荷载组合下进行稳定性分析,最后对该尾矿坝进行压坡处理,并对处理后的坝坡稳定性进行评价.结果表明:浸润线没有从坝坡出溢,水力坡降不大,渗流稳定.在现状正常运行和洪水运行条件下,该尾矿坝的稳定性系数均大于规范要求的最小安全系数,是安全稳定的.经过计算,特殊运行条件下(最高洪水位+坝体自重+地震的荷载组合),尾矿坝的坝体稳定性系数小于规范要求的最小安全系数,该尾矿坝的稳定性在特殊情况下运行是不稳定的.因此针对该尾矿坝进行压坡处理,并对处理后的坝坡稳定性进行了重新评价,评价结果显示该加固处理措施是有效的.     

钉结护面板对高土石坝坝坡地震稳定性影响研究

建立了考虑钉结护面板作用的土石坝坝坡地震稳定和滑移计算方法.在此基础上,对比分析了无加固措施和采用钉结护面板两种工况下295 m级两河口心墙堆石坝的坝坡稳定性.结果表明:采用钉结护面板后,坝坡最小安全系数对应的滑弧加深,安全系数明显提高,滑移量减小,有效地增加了坝顶的整体稳定性;随输入地震动峰值增加,钉结护面板对坝坡稳定安全系数的贡献逐渐增大.     

库水位骤降时坝体渗流场及坝坡稳定性分析

为了研究水位骤降时影响上游坝坡稳定性的因素,模拟坝坡在水位骤降时的渗流场及稳定性变化。基于土体渗透性,材料的非线性特性及水位下降率,利用有限元法对库水位变化下的渗流场进行瞬态分析,得出的自由水面线和孔隙水压力耗散等结果应用于上游坝坡稳定性分析,坝坡稳定分析采用极限平衡法。实例分析表明:计算区域渗流场变化滞后于水位下降的时间;坝体渗透系数越小,水位骤降对其稳定性的不利影响越显著;水位下降速率越大,上游坝坡稳定性降低越快。     

心墙坝坝坡稳定性对于邓肯E-B模型参数的敏感性研究

针对目前包括心墙坝在内的土石坝坝坡稳定敏感性研究存在的不足,从稳定和变形密切相关的角度出发,将对坝体变形较为敏感的模型参数考虑到稳定分析当中去,提出了一种新的研究思路.同时结合心墙坝工程实例,研究其上、下游坝壳及心墙土石料E-B模型参数对于坝体应力应变及坝坡稳定的敏感性.结果表明,不同部位、不同的模型参数对于坝体应力应变与坝坡稳定的敏感程度是不同的,对坝体应力应变较为敏感的模型参数对坝坡稳定同样具有较显著的敏感性.     

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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