基于衬砌结构受力的四洞并行公路隧道群施工相互影响分析

为研究多洞并行公路隧道群施工时各洞间相互影响规律,以成都天府机场高速公路龙泉山四洞并行隧道工程为背景进行数值模拟分析,研究后行隧洞开挖对先行隧洞围岩塑性区、初支受力及变形产生的影响.数值模拟结果表明:先行隧道初支受力及变形受后行相邻隧道开挖影响较大,且其影响随着隧道净距的减小和后行隧道断面的增大而增大;先行隧道初支压应力最大增量发生在靠后行隧道一侧的边墙部位,拉应力最大增量发生在拱顶部位.数值模拟以及现场监测均表明采用两侧2车道隧道先同时开挖,接着中间两3车道隧道依次开挖,同时相邻隧道掌子面错开距离控制在30 m的施工工序能够满足施工安全性要求,可为类似工程提供经验参考.     

偏压错台小净距隧道力学性态相似模型试验

试验研究了浅埋、偏压、错台条件下的小净距隧道力学性态相似模型,模拟不同的施工顺序(先开挖左洞和先开挖右洞)对隧道围岩及中间岩柱应力和沉降的影响.试验结果表明,在浅埋、偏压尤其是错台条件下,左洞和右洞开挖对中间岩柱的应力和位移均产生较大的影响;右洞先开挖引起整个上覆岩体的地表和深层沉降量比左洞大3%～48%,引起的两线隧道围岩中的应力释放量比左洞大3%～46%.左洞先开挖对隧道安全有利,应先开挖左洞.因此,针对平行的偏压小净距隧道应先开挖浅埋侧隧道的经验方法,对于错台不完全适用.数值分析和现场监测数据有力地验证了模型试验结果的合理性.     

基于围岩受力影响的小净距隧道开挖方法优化

为了确定某小净距隧道适宜的开挖方法,利用有限元软件对全断面法、台阶法和单侧壁导坑法进行模拟,分析不同开挖方法引起的围岩应力云图,并重点对不同的开挖方法引起先行洞围岩及中夹岩柱的受力变化进行对比。结果表明:隧道开挖后在两洞仰拱部位出现拉应力集中区,两隧道之间最近的中夹岩柱是受力最为显著的部位,不同的开挖方法在周边围岩中产生的应力大小及变化趋势也存在差异,全断面开挖方法对先行洞周边围岩影响较小,台阶法的施工在两洞之间引起的应力较小。由此确定该小净距隧道先行洞采用全断面法,后洞采用台阶法进行开挖,通过现场实施,证明方法可行。     

重叠隧道施工次序数值分析研究

本文利用ANSYS软件对水平重叠隧道断面进行计算，初步分析了在不同施工顺序下地层位移、围岩应力、结构内力的特点。结果表明：后施工隧道对先施工隧道有较大影响；开挖顺序不同，地层位移及塑性区亦不同，但开挖顺序对最终结构内力几乎无影响；先开挖下洞更有利。     

小净距隧道围岩受力特征的研究

文章以某小净距隧道为例,采用三维有限元数值模拟不同净距时左右洞开挖后中壁岩柱、拱顶位移及隧道周边的围岩受力状况,从上述分析可以看出,随着净距的减小,围岩（特别是中壁岩柱）受力将逐渐增加,拱顶位移将逐渐变大,同时随着围岩物性指数的降低,围岩将产生塑性区域,其受力状态将越来越不利。     

粉煤灰堆积体地层连拱隧道开挖错距影响分析

粉煤灰堆积体自稳能力差,受力即破碎成散颗粒,隧道穿越粉煤灰场区时失稳围岩对施工安全构成极大威胁。以盐坪坝连拱隧道为依托,根据粉煤灰力学性质对比选用了塑性-硬化本构,通过有限差分软件FLAC3D对不同开挖错距进行数值模拟,设置中导洞上下台阶以及左右洞开挖错距工况分别为5m、10m和15m,研究不同开挖错距对粉煤灰堆积地层中双连拱隧道的围岩和结构的影响。结果表明：中导洞台阶开挖错距不宜超过10m,15m错距相比10m错距应力最大值增长了36.82%,左右洞采用小开挖错距可以有效减少中导洞拱顶位移；中导洞开挖完成后左右洞拱顶竖向位移已达到其总沉降量约50%,左洞拱顶沉降位移与开挖错距近似线性增长,后行洞开挖过程中对先行洞造成的影响较大；主洞采用不同开挖错距时应力积聚分布在不同位置,开挖错距大于10m后结构受力增幅快速增长,15m错距相比10m错距应力最大值增长了17.28%。可见主洞开挖错距不宜超过10m。     

片麻岩大断面双洞隧道施工的动态特性

以兰州市北环路大断面双洞隧道工程为研究背景,采用台阶法进行施工,以ADINA有限元软件为计算平台,建立隧道开挖数值模型,对片麻岩大断面双洞隧道模型进行分析:研究地表位移、围岩位移与内力、锚杆轴力的特点及其变化规律.结果表明对片麻岩大断面双洞隧道采用台阶法施工时,分步开挖对地表竖向位移较水平位移影响大,最大竖向位移值为10.71mm,位于双洞隧道间岩柱上方;上、下台阶土体开挖会对隧道围岩位移及等效应力产生较大影响,应及时进行拱顶初期支护;锚杆轴力集中分布于边墙部位,且沿其辐射方向呈现不断减小的趋势,应对边墙部位锚杆进行加强处理.     

偏压情况下连拱隧道施工顺序的数值分析

采用有限元法数值模拟云南思小高速公路的双连拱隧道中导洞施工法分步开挖过程,研究双连拱隧道在偏压作用下施工过程的力学行为.通过动态数值模拟,得到隧洞在不同开挖顺序下围岩的应力变化和塑性区的发展范围以及中隔墙、衬砌的应力情况;对比分析不同施工方案各关键工序的模拟结果,并从应力转移的角度分析洞室开挖的影响,得到偏压作用下连拱隧道施工顺序的优选方案.     

高地应力软岩隧道超前平行导洞开挖对主洞影响：以玉龙雪山隧道工程为例

为研究高地应力软岩隧道超前平行导洞开挖对主洞影响,依托玉龙雪山隧道工程,基于现场长期监测数据,结合有限差分程序FLAC3D建立数值分析模型,研究超前平导对主洞围岩应力、围岩位移和塑性区分布的影响,明确主洞与平导间最优间距。研究结果表明:主洞开挖过程中,当掌子面与监测面距离为3.63倍主洞洞宽时,监测面拱顶沉降、上收敛、中收敛和下收敛值占最终变形值的80%以上,围岩变形稳定后上收敛值和中收敛值均大于拱顶沉降;平导超前开挖可有效改善主洞围岩应力环境,主洞与平导间距较大时,围岩应力改善效果不佳,随着二者间距逐渐减小,围岩应力改善效果逐渐增强,但主洞与平导间距过小时,二者开挖产生的塑性区会贯通,综合考虑,确定主洞与导洞最优间距为3.5倍导洞宽度;主洞拱顶沉降值和拱底隆起值随着主洞与平导间距的减小而增大,左右拱腰水平位移值随着主洞与平导间距的减小先减小后增大,当二者间距由5.0D减小至3.0D时,拱顶沉降值和拱底隆起值分别从-0.598m和0.426m增加至-0.679m和0.514m。     

水下并行隧道施工后行洞对先行洞的影响分析

以实际水下隧道为工程背景,建立数值模型,分析水下并行隧道后行洞施工对先行洞的影响.结果表明：后行洞施工主要影响距离该断面位置前后1.5倍洞径;后行洞施工后,围岩沉降分布形态发生变化,在左右拱顶较大,在两洞之间及两侧较小,即出现了“驼峰”;对于最大主应力,后行洞施工对靠近侧的右边墙影响较大;随着后行洞的施工,渗流影响范围逐渐向后行洞侧扩展,隧道周边渗流量的大小呈现拱顶和仰拱处的大于边墙的,而后行洞和先行洞之间的边墙渗流量大于外侧边墙的渗流量.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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