盖挖逆作法与明挖顺作法施工变形控制对比

为更好地验证盖挖逆作法施工相对于明挖顺作法对该工程适用性更优及在变形控制方面的优势所在,针对长春火车站南广场交通枢纽中心工程周边环境复杂,场地十分复杂,同时开挖面积大、形状不规则,基坑形式复杂的特点,在同等控制前提下采用盖挖逆作法和明挖顺作法进行施工.通过FLAC3D模拟两工法下的施工过程,分别探究基坑周围地表和结构自身的变形情况,对比分析更具优势的工法.分析结果表明,在地下结构变形控制方面,原工程选用盖挖逆作法要优于明挖顺作法.     

盖挖逆作法地铁车站结构体系内力及变形研究进展

因地铁车站周围环境复杂,而盖挖逆作法具有围护结构变形小、地面沉降小、缩短中断交通时间、低噪音、少粉尘、不扰民等优势,故被广泛应用于地铁车站的施工中。从盖挖逆作法地铁车站的围护结构、各层楼板、中间桩柱三方面介绍了各结构部位的内力及变形,分析了中桩柱之间、中桩柱与相邻地下连续墙之间的差异沉降特征,提出已有盖挖逆作法地铁车站结构体系内力及变形分析的建议和接下来有待进一步开展研究的内容,为相关理论研究的专家学者提供了一个新的研究动态,也可为工程建设人员提供一定的支持。     

框架逆作深基坑变形特性离心模型试验

以某超大型深基坑工程为背景,通过离心模型试验比较了新型框架逆作法与传统逆作法的施工方案基坑变形控制的效果;基于试验结果,研究了地表最大沉降与围护结构最大侧移之间的关系,以及地表沉降大小和影响范围.试验结果显示:框架逆作基坑地表最大沉降基本为围护墙最大侧移的0.35~0.70倍,而无支撑暴露时间对二者比值的大小有一定影响;基于实测总结的国内外多种经验地表沉降预测方法并未能很好地预测试验结果;框架逆作法与传统逆作法施工方案基坑变形控制的效果大致相当,框架逆作法方案可以达到有效控制基坑变形的目的,该结论对于框架逆作法在实际工程中的推广应用具有重要参考价值.     

临河深大复杂基坑变形分析

文章以合肥地铁1、2号线交叉换乘车站大东门车站复杂深大基坑工程为研究背景,通过MIDAS-GTS有限元分析软件,分别建立车站整体三维模型、1号线单独模型和1号线车站截断模型,对其盖挖逆作施工过程进行数值模拟,重点研究在不同河水水位情况下,基坑围护结构变形和地表沉降的变化规律,并和现场的监测数据进行分析对比.结果表明,所建模型可以较好地模拟不同施工条件下的基坑变形,研究所得相关结果可供设计和施工提供参考依据.     

长江漫滩地区深大基坑开挖工程半逆作半顺作法研究

针对长江漫滩高承压水地基,以南京市某工字型地下6层地铁换乘站基坑为依托工程,采用FLAC3D三维有限差分软件,分别对半顺作半逆作开挖法和明挖顺作法进行数值模拟,分析了基坑开挖及降水的应力渗流耦合作用对周围地表沉降、连续墙侧移和支撑轴力的影响。结果表明：1)长江漫滩高承压水地基深基坑开挖工程,地表沉降值和连续墙变形值均较大;2)工字型深基坑开挖工程,地表沉降、连续墙侧移最大值出现在上下横边中点处;3)半顺作半逆作法的地表沉降、连续墙侧移、横向支撑轴力值均小于明挖顺作法,更有利于控制基坑侧壁变形,降低基坑开挖风险。     

群坑效应下已建地下结构对紧邻基坑开挖变形的影响

目的研究软土地区深基坑分区开挖时已建地下结构对紧邻基坑围护结构变形及其周边位移场的影响.方法采用三维数值模拟方法,针对软土地区某"X"型地铁交叉换乘站工程,分别建立后开挖基坑周边有无地下结构两种工况下的数值模型进行计算,将所得计算结果与实测数据进行对比研究.结果已建地下结构对周边环境的主要影响范围为0.7 H_e～1.0 H_e(紧邻基坑开挖深度);相较基坑周边无地下结构条件下,已建地下结构最大可减小30%紧邻基坑围护结构变形值与坑后地表沉降量,但其对坑内基底隆起影响不大;已建地下结构与紧邻基坑所夹角度对影响范围与影响效果也存在着显著的影响,具体表现为处于相交成锐角区域的墙体变形和地表沉降较相交成钝角的区域减少20%,交接成锐角区的影响范围也较钝角区增加50%.结论已建地下结构在一定影响范围内可以显著减少紧邻基坑围护结构的变形量及周围地表沉降量,在实际施工中可以适当降低该区域内围护结构刚度以优化基坑设计.     

相邻双基坑开挖相互影响二维性状分析

以某实际相邻双基坑工程为原型,利用PLAXIS建立相邻基坑开挖的二维模型,采用HS土体本构模型,分析相邻基坑同步开挖对土体位移、支护结构变形与内力的影响;考虑不同开挖工序和不同基坑间距,分析相邻基坑开挖的影响范围和基坑支护结构在不同开挖工序下的变形特征.对相邻基坑同步开挖下的支护结构位移进行了实测.结果表明,邻近基坑开挖卸荷对基坑间土体沉降、坑底隆起、坑外地表沉降、支护结构内力与变形等产生明显影响.相邻基坑间距、开挖顺序和支护方式是其主要影响因素.     

异形深基坑支护设计与变形特性分析

受地下空间及主体结构功能需求,异形深基坑在基坑工程建设中运用日益广泛.针对该类型基坑的工程特性,以南昌市某典型的异形深基坑项目为依托,阐明基坑围护体系形式及支护控制要点.并采用MIDAS/GTS NX有限元分析软件建立基坑三维仿真模型,探讨基坑围护结构变形及周边地表沉降规律.通过有限元数值计算结果,验明该围护体系在工程中可有效适应异形基坑的支护变形特性,并积极抵抗基坑侧向变形,为异形深基坑提供优质的安全保障.     

MC桩组合支护结构在淤泥质土基坑工程中的应用分析

结合某淤泥质土环境基坑支护工程实例,采用有限元数值分析方法,探讨水泥土桩与混凝土桩组合支护结构（MC桩）力学变形特性,包括MC桩截面参数对支护结构水平位移、地表沉降以及坑底隆起量影响．研究结果表明,MC桩组合支护结构在淤泥质基坑中,有利于控制基坑变形,增加基坑稳定性;M桩挡墙宽度对减小支护结构变形效果明显,增大墙宽可以减小墙身弯矩以及支护结构墙体倾斜变形并且可降低坑底隆起量和坑外地表沉降量．而且,在同挡墙宽度情况下,有无C桩对控制支护结构变形和基坑变形也有很大的作用．     

软土区管廊基坑柔性支护下基坑变形控制标准

软土区基坑工程中,控制基坑变形十分重要。本文对广州南沙柔性支护的管廊基坑进行有限元分析,得到了开挖过程中基坑的变形特征,开挖到基坑底部时,围护结构桩身变形由“悬臂式”变为“内凸型”,围护结构达到最大水平位移值31.92mm;地表沉降与坑底隆起最大值为22.26mm、54.81mm;稳定性计算结果为2.2,基坑变形及稳定性均满足规范要求。继而研究了6个不同基坑断面在临界失稳状态与稳定性满足规范这两种条件下,围护结构水平变形、地表沉降、坑底隆起的变形最大值占基坑开挖深度的百分比,建议将计算结果的平均值作为控制值的参考值。基坑临界失稳状态下,设计安全等级为二级、三级的基坑围护结构水平变形控制参考值分别为基坑深度的2.62%、3.24%。基坑稳定性满足规范要求时,设计安全等级为二级、三级的基坑围护结构水平变形控制参考值分别为基坑深度的0.8%、0.93%。     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-