盾构隧道下穿砌体结构的洞内深孔注浆加固参数分析

以盾构隧道下穿砌体结构房屋为背景,以墙体最大拉应力增量为评价指标,分析洞内深孔注浆加固技术中径向加固半径、建筑物前后加固范围和隧道断面加固范围这3个主要技术参数在盾构隧道下穿砌体结构过程中对砌体结构的影响,并采用正交试验方法,确定主要技术参数影响洞内深孔注浆加固效果的主次顺序.结果表明：洞内深孔注浆技术可以对隧道周围的地层进行有效加固,减少盾构隧道施工对上部砌体结构房屋的扰动;对隧道周围进行全断面注浆时,加固效果最好;径向加固半径超过5m,建筑物前后加固范围超过1.5倍隧道直径时,注浆加固效果不再明显;在影响洞内深孔注浆加固效果的主要技术参数中,隧道断面加固范围对加固效果的影响最大,其次为径向加固半径,影响最小的为建筑物前后加固范围.     

合肥典型地层双线盾构近接下穿对高铁桥群桩的影响

为了了解合肥典型地层双线盾构近接下穿对高铁桥群桩的影响,以合肥地铁3号线盾构隧道施工近距离穿越高铁桥桩基群工程为例,利用有限元分析软件对盾构施工的全过程进行三维动态模拟,通过分析盾构施工过程中桩身横向位移、弯矩、轴力分布等变化规律,研究了双线盾构近接下穿对高铁桥群桩的扰动规律。结果表明:盾构隧道施工在穿越桩基础群时,距离盾构掌子面较近的桩受到的影响明显大于较远位置的桩;当盾构掌子面推进到与桩群相交处时产生的施工扰动最大;桩基础在盾构中心线上下一倍洞径深度范围内所受到的盾构施工扰动影响最大,桩身轴力和弯矩明显大于其他部位;且双线盾构隧道的后施工隧道的开挖使得先施工隧道周围桩基受到的扰动幅度得以降低。     

粉质砂层地铁盾构下穿浅基础房屋地表沉降控制研究

以武汉某盾构隧道下穿浅基础房屋工程为依托,通过结合FLAC3D软件对不同开挖方式、施工参数盾构下穿浅基础房屋地表沉降进行研究。研究表明：分线开挖较同步开挖对地层扰动更大,在右线掘进到达建筑物正下方时,同断面地表沉降差10.44 mm,建筑物可能产生不均匀沉降开裂;不同建筑荷载对地表沉降影响规律基本相同,随着建筑荷载的增加,地表沉降增加的同时,建筑中间受挤压隆起值也随着增加;不同施工参数下,同步注浆压力能有效减小盾构通行过程中地表沉降速度,有效控制地表不均匀沉降,土仓压力对盾构掌子面前方土体的扰动较通过时地表沉降影响明显。研究成果对盾构下穿建筑物地表变形规律及控制具有较强的实用性和指导意义。     

卵石地层中地铁盾构近距下穿盾构隧道施工沉降控制

为研究卵石地层条件下盾构下穿施工时既有盾构隧道的沉降特征及其控制措施,依托北京地铁16号线盾构下穿既有地铁4号线盾构隧道工程,通过分析既有隧道沉降的数值模拟结果,结合现场监测数据和盾构施工参数,探讨了盾构的适应性改造,总结了隧道沉降的规律,阐明了调控盾构施工参数的经验。研究表明,为适应卵石地层条件,盾构须提高构件耐磨性、增设注浆及泡沫系统;既有隧道沉降在盾构通过时变化较大,而在盾构到达前和通过后变化较小,且盾构施工的再次扰动影响显著;为有效地控制既有隧道沉降,盾构施工参数应根据监测数据实时调控,保持较高的土仓压力和顶推力,通过提高注浆压力确保注浆质量。     

砂卵石地层地铁近接下穿既有盾构区间施工控制技术

为探究地铁暗挖近接施工下穿既有盾构区间加固技术适应性,以成都5号线近接下穿既有3号线为工程背景,提出适应于成都砂卵石地层的预埋注浆加固保护方案,且通过数值模拟研究了不同注浆加固范围的保护效果、注浆过程对隧道结构影响以及对下穿过程规律性进行讨论,并结合现场监测分析.结果表明:既有隧道注浆加固范围扩大,其隧道结构变形呈线性减小,隧道结构纵向沉降槽呈线性缩小,适当增大既有隧道注浆范围可控制其变形量;预埋钢花管注浆加固过程中,浆液压力和土体硬化将导致既有隧道结构竖向产生沉降,水平方向相向靠拢;地铁下穿过程中,既有隧道结构主要产生竖向沉降,先缓慢沉降,隧道穿过后沉降变形突增,再趋于稳定,前期有一定反应阶段;相比既有隧道,近距离的大范围注浆加固导致土体硬化,5号线结构变形预变形阶段极大缩短,反应时间短,施工风险增大.提出二次衬砌工序优化、深孔注浆加固补救措施以及节点位置格栅密排等措施能够降低既有盾构运营风险.     

流固耦合作用下盾构下穿高架桥稳定性分析

本文依托太原铁路枢纽新建西南环线盾构隧道,结合盾构施工中的监测资料,利用有限元分析软件进行数值模拟分析,在考虑流固耦合作用下,并结合实际监测资料,研究了盾构下穿高架桥时地表和地下结构的稳定性,得出了地表、桥承台和桥桩的变形规律及隧道周围孔隙水压力分布规律。研究结果表明：在富水地层中盾构下穿高架桥工程中,考虑流固耦合作用是必要且合理的;盾构隧道施工前采用隔离桩结合深层地层注浆的加固措施能有效地控制地表、桥承台和桥桩变形;盾构掘进过程中主要影响桥桩水平横向位移,对水平纵向和竖直方向位移影响较小;桥桩顶部受到的附加弯矩较大;深层地层注浆加固措施能减弱隧道周围流固耦合作用,降低隧道内涌水风险。     

盾构施工对黄土地层的扰动及管片衬砌受荷特征

为探明黄土地层中地铁盾构隧道施工对地层的扰动以及管片衬砌结构承受荷载的特征,依托西安地铁2号线穿越黄土地层盾构隧道工程,采用颗粒离散元方法从细观层面对盾构施工引起的地层应力变化及开挖面失稳形态进行模拟分析,同时对实际作用在管片衬砌结构上的土压力和主体结构内力(轴力、弯矩)进行现场动态跟踪测试,分析盾构动态施工过程及后期稳定后的土压力对管片衬砌结构受力的影响.研究结果表明:临空面的产生导致隧道拱顶及两侧部分水平应力和垂直应力发生显著变化.管片衬砌结构内力受施工参数影响明显,尤其是千斤顶推力和注浆压力.     

浅覆地层盾构隧道下穿永宁门护城河的施工方案研究

以西安地铁二号线地铁隧道下穿永宁门护城河工程为依托,根据具体的工程地质和水文地质情况,利用开挖面的最小支护力原理,得出了盾构掌子面土仓内压力的安全范围,并就施工中河道内地表隆起较大的问题提出相应对策。采取在河道内堆载,并在盾构施工中合理控制土仓压力的措施,能有效控制地层变形,防止地表隆起。施工中的地层变形监测数据表明,提出的施工方案和技术措施正确可行,对未来类似条件下的隧道施工具有良好的参考价值。     

天津市软土地层地铁盾构区间下穿施工对京沪高铁南仓特大桥影响的数值分析

为研究天津地区软土地层隧道盾构区间下穿施工对京沪高铁南仓特大桥的影响,以下穿京沪高铁的天津地铁7号线外院附中站-榆关道站区间隧道工程为背景,对下穿京沪高铁南仓特大桥段区间盾构隧道进行设计,通过运用Midas/GTS有限元软件数值分析方法对盾构区间下穿京沪高铁南仓特大桥进行有限元数值分析。研究盾构区间下穿京沪高铁南仓特大桥施工过程中桥面、桥墩、承台及桥桩位移变化规律特征。总结盾构区间侧穿桥桩施工过程中桥桩附加应力变化规律;揭示了盾构区间下穿京沪高铁特大桥施工过程中承台差异沉降及地层应力变化规律。结果表明,盾构隧道施工过程中京沪高铁天津南仓特大桥桥桩附加弯矩较小,桥面、承台、桥墩及桥桩沉降最大值均在控制标准值范围以内,桥桩水平位移最大值在控制标准值范围以内,不会对大桥产生破坏影响。可见在软土地区盾构施工对高铁特大桥有一定程度影响,但通过施加工程措施后,可有效降低对桥的影响程度,保证高铁桥的安全。研究成果可为类型工程施工设计提供参考。     

上覆薄煤层采空区公路隧道开挖稳定性试验研究

隧道下穿煤层采空区施工将对周围地层产生扰动,影响隧道围岩及初期支护的稳定性.进行了上覆薄煤层采空区隧道开挖的室内相似模型试验,试验中通过测量隧道开挖过程中采空区地层、隧道拱顶的沉降及初期支护内力等参数,对上下台阶法和单侧壁导坑法进行了对比分析.测试结果表明,隧道开挖引起的采空区地层沉降受开挖方法的影响显著,上下台阶法开挖引起的采空区地层沉降高于单侧壁导坑法,沉降槽曲线较陡、沉降范围更宽.两种开挖方法中,围岩压力的最大值均位于右拱脚处,钢拱架最大弯矩出现在拱脚处,最大轴力位于拱腰或拱肩处.其它条件相同时,采用单侧壁导坑法开挖时初期支护背后的围岩压力、钢拱架内力和偏心距等普遍大于上下台阶法开挖.研究表明在隧道下穿倾斜煤层采空区施工时,采用单侧壁导坑法开挖可以显著减小对采空区地层及围岩的扰动,但同时需增强初期支护的刚度,确保围岩及隧道结构的整体稳定性.     

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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