长江口软土的压缩特性及围堤沉降预测分析

针对长江口地区软土沉降预测困难的问题,进行了一系列原状软土与重塑软土固结试验,以研究软土的固结和次固结特性.探究长江口软土的压缩指数范围、次固结系数与荷载的关系等,对长江口软土、典型上海软土及崇明岛软土工程特性进行了对比.采用两种沉降计算方法对工后沉降进行计算及预测,并分析两种方法的实用性.试验结果表明:长江口地区淤泥质粉质黏土压缩指数为0.316～0.364,淤泥质黏土为0.267～0.313,略大于典型上海软土的压缩指数;原状土次固结系数随荷载的增大,先增大后减小,重塑土次固结系数与荷载无关;长江口软土次固结系数大于典型上海软土的次固结系数.长江口软土与典型上海软土及崇明岛区域软土物理性质指标有一定差异.     

软土分析

软土是工程中常见的一类土,工程性质较为特殊,是地基工程中的重点与难点。文章以软土概况为出发点,总结软土的性质,从原理上分析软土抗剪强度,简单描述软土沉降的基本组成部分和沉降计算方法。     

砂黏复合地层盾构隧道施工地表横向沉降分析

依托广州地铁二号线洛溪—南浦区间盾构隧道工程,选取其中处于砂黏互层地层的六个监测断面对其横向沉降进行研究。选择能反映沉降槽偏移的高斯峰值函数拟合实测的沉降数据,得到沉降槽宽度系数、最大沉降量等横向沉降特征的重要参数;并对监测断面的沉降槽对称性进行分析。根据现有的沉降槽宽度系数预测理论,提出了更适合砂黏互层地层沉降槽沉降系数的计算方法;并与拟合值进行了比较。与软土地层、砂砾土地层的沉降槽宽度系数对比,结论表明在等效洞径比相近的情况下沉降槽宽度:软土地层砂黏互层地层砂砾土地层。     

砂粘复合地层盾构隧道施工地表横向沉降分析

文章依托广州地铁二号线洛溪—南浦区间盾构隧道工程,选取其中处于砂粘复合地层的六个监测断面对其横向沉降进行研究;选择能反映沉降槽偏移的高斯峰值函数拟合实测的沉降数据,得到沉降槽宽度系数、最大沉降量等横向沉降特征的重要参数,并对监测断面的沉降槽对称性进行分析;根据现有的沉降槽宽度系数预测理论,提出了更适合砂粘复合地层沉降槽沉降系数的计算方法,并与拟合值进行了比较; 与软土地层,砂砾土地层的沉降槽宽度系数对比,结论表明在等效洞泾比相近的情况下沉降槽宽度：软土地层＞砂粘复合地层＞砂砾土地层。     

深厚软土先预压后换填泡沫混凝土轻质路堤现场试验研究①

针对深厚软土路基压缩性大和工后沉降控制难的问题,以温州绕城高速公路西南线工程为依托,提出了先预压后换填泡沫混凝土施工技术,对典型断面卸载前表层累计沉降和换填泡沫混凝土后关键节点沉降进行监测,对该处理方式的加固效果进行了评估。研究表明:典型断面在卸载前表层沉降约为2m,表明深厚软土预压期沉降量大;建议下一级加载前沉降速率小于5mm/d,为了保证软土沉降;在运营半年后典型断面最大沉降为4mm,预测运营15a后累计沉降为62mm,低于设计标准值。说明采用先预压后换填泡沫混凝土的方法能有效的处理深厚软土路基,可为类似工程提供参考。     

软土工后沉降双曲线模型与指数曲线模型分析

分析软土工后沉降的典型预测模型,指出了预测误差的原因.阐明双曲线模型只是基于模型曲线与实测沉降形状相似的基础上提出的,没有理论依据;指数曲线模型主要基于太沙基一维固结理论,模型假定与工程实际有较大出入,所以两者具有较大的拟合误差.从数学角度证明了在初始沉降速率和最终沉降分别相同的情况下,指数模型预测结果大于双曲线模型的预测结果.沉降预测工程实例进一步证明了数学分析的正确性.讨论了理想工后沉降模型应具备的数学性质.     

Peck公式在砂卵石地层盾构隧道施工地表沉降预测中的应用研究

基于乌鲁木齐砂卵石地层地铁隧道现场监测数据,采用回归分析方法对典型断面地表沉降进行分析,得到适用于砂卵石地层的Peck公式,并进行了现场数据验证.研究成果表明得到的peck公式能够有效预测砂卵石地层盾构施工地表沉降,具有工程指导意义.     

大型群桩-软土共同作用性状研究

以某水闸工程为研究对象,应用有限元方法对大型群桩与软土地基共同作用性状进行了研究.建立三维非线性有限元模型,通过改变影响沉降参数和桩体布置方式、桩径、桩端土性质等,分析了群桩沉降性状.结果表明,在实际工程中,桩直径以800~1 000 mm为优,桩端部土体用于持力层的土体弹性模量不宜小于400 MPa.     

某填海工程海上通道固结变形及沉降监测分析

在分析海相软土工程性质和借鉴日本关西机场工程经验数据的基础上,基于Terzaghi一维固结理论以及二维Biot固结理论,分别进行某大型填海造地工程海上通道的一维和二维固结沉降数值模拟分析,得出海上通道沉降分析结果与规律,并与采用双频GPS和高精度水准仪相结合的方法联测出的沉降监测数据进行对比,预测海上通道最终沉降量.计算结果表明:沉降分析结果与实测数据吻合较好,预测的海上通道沉降、超静孔隙水压力发展趋势及最终沉降量可靠.     

深层承压水降水引起地层沉降的多工况数值模拟

基于上海某地铁换乘枢纽地下综合体工程背景,借助Geo Studio2007岩土工程有限元数值分析软件,针对上海地区第二层承压水降水及其引起的地层沉降进行数值模拟,考虑了两种降压井布置方式,设置了原位无基坑、单个基坑和多个基坑三种工况,并对各工况下降水后的地层沉降作了对比分析.研究表明,在对第二层承压水设定相同的水位降深时,三种工况下地表沉降值的相对大小关系随距离降压中心位置的变化而变化;基坑围护结构对于地表沉降存在隔断作用,有利于地表沉降的收敛;降压井的不同布置形式影响着三种工况的最大地表沉降值;对第二承压含水层实施降压,只会在该土层引起压缩变形,其上覆各土层的地层沉降基本相同.本文的研究成果对于软土地区多基坑遭遇深层承压水降水问题具有一定的指导价值和借鉴意义.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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