基于ANSYS的深基坑变形数值模拟研究——以宜昌城区深基坑工程为背景

根据宜昌城区的工程地质条件、地基土特性以及现有的深基坑工程特点,通过大型通用有限元软件ANSYS分别建立了喷锚支护开挖的深基坑模型、桩锚支护开挖的深基坑模型和放坡无支护开挖的深基坑模型,借助ANSYS的"单元生死"功能,模拟了深基坑在上述3种开挖形式下的分步开挖过程,并对模拟结果进行分析,得出了深基坑在分步开挖过程中的...     

地铁车站深基坑开挖监测与数值模拟研究

以郑州市某地铁车站的深基坑工程为研究背景,运用有限元分析软件MIDAS/GTS NX建立整体有限元模型,对基坑开挖的每步施工过程进行数值模拟。探讨了深基坑开挖过程中地连墙的水平位移、周围地表沉降及内支撑轴力分布情况,用于判定深基坑在开挖过程中的稳定性和安全性。同时分别对深基坑开挖过程中周围的建筑物沉降、墙顶水平位移和沉降及支撑轴力进行了监测,并与数值模拟值进行对比。结果表明:理论计算值与现场监控值变化趋势基本一致,结果误差不大,均在设计报警值以内;墙体水平位移随着开挖深度增加而增大,且最大的位移逐渐向下移动,土体地表沉降的变形基本随着开挖深度的增大而逐渐增大,但内支撑轴力不随开挖深度的增大而增大,而是呈现波动的变化趋势;在深基坑开挖过程中,应重点对开挖引起的对墙体变形、地面过大变形和支撑结构内力进行监测。研究结果表明监控量测与数值模拟相结合能较好地运用于基坑开挖,也可为类似基坑工程的开挖提供一定的借鉴作用。     

地下连续墙在邻近地铁基坑开挖中的应用

在城市建设的过程中,临近地铁隧道的深基坑开挖越来越普遍.以实际工程为背景,探讨了地铁连续墙作为基坑支护的特点,以及在实际工程项目中的应用效果.从而表明为在深基坑的开挖过程中,地下连续墙作为基坑支护的优越性.     

兰州地铁红砂岩基坑开挖监测与数值模拟分析

以兰州市东方红广场地铁车站红砂岩深基坑为研究对象,对基坑开挖过程中围护桩位移和基坑周边地表沉降进行现场监测,并对实测结果进行分析;采用MIDAS GTS数值模拟软件,分别建立深基坑开挖支护和渗流分析的三维模型,对深基坑在开挖过程中的位移进行模拟计算.结果表明:桩的水平位移随桩体嵌入深度先增大后减小,整体呈")"形前倾,...     

地铁车站深基坑开挖对土体影响的数值模拟

为了研究地铁工程支护结构对周围土体变形影响的问题,应用有限元计算软件ADINA对地铁车站深基坑工程进行开挖支护模拟,建立明挖法深基坑开挖支护过程的三维模型,分析开挖过程中连续墙支护开挖和连续墙、锚杆联合支护开挖两种工况下,基坑周边地层的位移情况.研究结果表明:地铁车站深基坑的开挖与支护过程是一个基坑支护结构和基坑内土体、基坑周围土体共同作用的问题,支护结构和支护方法对基坑周围环境的影响明显,周围土体和基坑内土体对基坑性状的影响显著.     

深基坑开挖监测技术及运用

深基坑工程的建设不仅取决于合理的设计、施工,而且取决于贯穿在工程设计、施工全过程的监测。监测是深基坑工程安全的重要保证条件之一。在深基坑开挖过程中,由于地质条件、荷载条件、材料性质、施工条件和外界其他影响,基于各种条件下的监测有利有弊。本文具体探讨了几种深基坑开挖监测技术及其在实际中的案例运用。     

武汉地铁循礼门车站基坑施工稳定性分析

在建武汉市轨道交通二号线一期工程循礼门站轨道交通车站地质条件复杂多变,基坑周边环境复杂,施工安全是施工的关键问题之一.论文以该工程为背景,运用深基坑设计软件对标准段的深基坑开挖过程进行数值模拟和分析,最后得到了深基坑开挖过程中土体及支护的变化规律,为工程的施工提供了理论依据和借鉴.     

深基坑回弹的空间性状研究

提出了深基坑回弹空间效应分析的三维有限元模型．该模型模拟了深基坑分步开挖过程和支撑方式的变化，土体采用修正剑桥模型．同时定量地分析了基坑形状、基坑开挖面积以及开挖深度等因素对基坑开挖回弹量的影响．所提出的回弹计算方法可以为工程师有效地预估深基坑工程中不同基坑形状、不同开挖面积和深度的回弹提供依据．     

基于开挖方法对深基坑变形的分析与施工优化

为研究开挖方式对深基坑变形分析与施工优化,采用有限元软件FLAC3D对上海某深基坑开挖进行模拟.通过改变开挖方式,在数值计算中设置若干种工况,研究开挖过程中的基坑围护结构位移变化、地表沉降.研究结果表明:3种不同的开挖方法对于基坑变形的控制能力依次是台阶式退挖、跳挖、竖向顺序分层开挖.在采用了新的开挖方式后,基坑周边的最大沉降值也由之前的10 mm左右减小到8 mm左右,基坑围护结构最大水平位移由原来的45 mm减小到40 mm,说明新的开挖方式有效的控制了深基坑变形.     

深基坑桩锚支护结构中帷幕的作用分析

在郑州市区,桩锚支护结构是最常用的深基坑支护型式之一,但在地下水位较浅,基坑开挖过程中需要采取降水措施,周围环境较复杂的深基坑,桩锚支护结构中是否设置帷幕存在一定的争议.对郑州市区的两个深基坑开挖后实际情况进行对比,这两个深基坑地理位置和地层情况相近,但其中一个设置了高压旋喷桩帷幕,一个没有设置帷幕,对帷幕在深基坑桩锚支护结构中的作用进行了分析.     

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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