全埋式抗滑桩合理桩间距模型试验研究

基于室内模型试验,对3种不同桩间距的全埋式抗滑桩进行受力特性研究,对比2倍、3倍及5倍桩间距抗滑桩的阻滑能力。试验结果表明:在相同水平推力荷载作用下,2倍桩间距的桩顶位移最小,其次为3倍桩间距,5倍桩间距的桩顶位移最大,阻滑效果不明显;对桩身弯矩的监测结果表明,抗滑桩桩身弯矩最大值点呈下移的趋势,不同高度处桩身弯矩具有明显差异,桩顶与桩底弯矩值较小;3种模型桩的土压力均呈现出上下小,中间大的近似抛物线分布,其中2倍桩间距抗滑桩土压力分布较均匀,有利于桩后承载土拱形成。     

怀邵衡铁路DK324边坡坍滑分析及处理方案优化

怀邵衡铁路DK324路堑边坡开挖后坍滑而形成滑坡,通过现场勘探、调查测绘、原位测试及室内试验对边坡坍滑体的空间形态、坍滑体物质组成、结构特征及水文地质进行调查,分析了边坡坍滑成因.利用有限元方法对单排桩、双排桩和刚架桩三种抗滑桩进行计算,对比不同桩型的弯矩、剪力和水平位移,结合现场施工的安全因素,确定了刚架抗滑桩处理方案.长期监测数据表明,刚架抗滑桩的处理效果明显.该方案对同类工程有一定借鉴和指导意义.     

拱形抗滑结构模型试验研究

针对拱形抗滑结构治理黄土地区滑坡的适用性,通过3组室内物理模型试验,对比分析拱形抗滑结构的桩后土压力、桩顶位移、桩身弯矩及连梁受力变形特征。结果表明：3种工况下抗滑桩桩后土压力基本一致,呈三角形分布;桩身弯矩的变化规律基本相同,呈先增大后减小再增大的趋势;直线形布置的抗滑桩桩顶切向位移几乎为0,桩顶法向位移最大值为13.56 mm;当采用钢管混凝土桩拱形布置时,桩顶切向位移为1.41 mm,桩顶法向位移为2.65 mm;当采用竹管混凝土拱形布置作为临时救灾抗滑支护结构时,桩顶切向位移为1.55 mm,桩顶法向位移为2.81 mm;采用拱形抗滑结构对桩顶水平位移有较好的约束作用,同时还可改善桩身受力状态。     

围桩平面布置及其内力分布的数值分析

采用三维有限差分软件FLAC3D分析新型围桩-土耦合式抗滑结构,建立该新型抗滑结构的计算模型.通过分析不同围桩平面布置下的桩-土位移,确定围桩的合理平面布置,即6根围桩,呈正六边形布置(前、后两条边均垂直于滑坡推力方向),围桩中心距s=5d.在此平面布置下,分析并得出抗滑结构中各围桩的内力分布规律,即各围桩弯矩、剪力分布一致,中间和后排围桩受拉,前排围桩受压.     

高速公路改扩建工程边坡抗滑桩加固效果数值分析

为了分析改扩建工程中使用抗滑桩对边坡加固治理时的支护稳定性,基于FLAC3D软件对某改扩建边坡利用抗滑桩加固效果进行数值模拟,得到边坡的应力应变云图、桩身前后岩体压力及桩自身内力的分布规律。研究结果表明:抗滑桩的阻挡作用使桩周岩体局部应力增加,抗滑桩处的剪应变增量增大;抗滑桩前、后的岩土压力呈三角形分布,边坡滑裂面以下岩土压力分布复杂,可近似认为属于梯形或矩形分布;抗滑桩桩体在滑裂面位置处的剪力和弯矩最大。     

双排抗滑桩与门架抗滑桩的有限元分析对比

对于滑坡推力很大的大型滑坡,常可能需要采用两排或两排以上抗滑桩进行治理。为合理确定滑坡推力在各排桩上的分布形式或大小,计算各排桩的实际受力和变形,采用ABAQUS有限元软件,建立了双排抗滑桩和门架抗滑桩治理顺层滑坡的三维数值分析模型。通过在桩—土间设置库仑摩擦接触面模拟桩—土相互作用,用滑带岩土体强度折减方法来施加滑坡推力,探讨双排抗滑桩和门架抗滑桩的受力情况,对二者的位移、内力、桩身土压力分布进行了对比分析,研究结果表明,后者的位移、内力明显小于前者,说明门架抗滑桩受力更为合理,是更值得推广的抗滑支挡结构形式。     

渗透作用下滑坡-抗滑桩变形特征分析——以马家沟滑坡分析为例

基于Drucker-Prager模型,以马家沟滑坡为分析对象,从水平抗力、位移的角度出发,利用有限元分析软件ABAQUS对库水位波动时渗透力作用下滑坡发育过程中滑坡-抗滑桩不同位置处的变形规律进行了研究。研究表明,库水位波动时,抗滑桩土体水平抗力及位移随渗透力的增大而增大;0~60 d,滑坡变形过程经历瞬间加卸荷变形、应力调整变形、应力稳步增长变形3个变形过程;0.5~40 d滑坡位移速率持续降低,滑坡处于减速蠕变阶段;40~100 d滑坡位移速率趋于稳定,滑坡处于等速蠕变阶段。滑坡位移速率趋于稳定时,土体的变形处于缓慢持续的状态,体现出马家沟滑坡的蠕滑特性;抗滑桩桩前、桩后水平抗力及位移呈现时间效应。     

抗滑桩-加筋土挡墙组合支挡结构开发

针对山区陡坡地形上加筋土挡墙抗滑稳定性的不足,提出抗滑桩+刚/柔组合墙面加筋土挡墙组合支挡结构,阐述该组合支挡结构的研发思路、结构形式和技术特征。采用有限差分程序FLAC3D建立该组合支挡结构的数值模型,对比分析抗滑桩和抗滑桩+承台2种结构的加筋土挡墙墙面水平位移、抗滑桩位移和桩身弯矩、土工格栅拉力及路基稳定性,重点探讨抗滑桩桩长、覆盖层模量和上覆荷载的影响。研究结果表明:在抗滑桩顶部设置承台可以有效减小墙面和桩身水平位移,提高路基稳定性;将抗滑桩和承台的连接方式由刚接改成铰接会使桩身弯矩显著减小,而对墙面和桩身位移及路基稳定性影响不大;未设置承台时墙面和桩身水平位移更容易受到抗滑桩桩长、覆盖层模量和上覆荷载变化的不利影响。     

承重阻滑桩受力特性分析

承重阻滑桩在山区高速公路建设及山区城镇建设中应用广泛,具有承重与阻滑双重作用,其受力性状远比抗滑桩和平地上受荷桩复杂.本文采用整体有限元法,对影响承重阻滑桩内力的桩顶荷载、地下水高程和地震荷载三类工况进行计算.通过对计算结果的分析探讨,得到一系列的结论,对承重阻滑桩的设计有一定的指导作用.     

抗滑桩锚固长度对均质边坡滑动面及抗滑能力影响研究

利用透明土技术开展不同锚固长度抗滑桩加固均质边坡可视化模型试验,并结合粒子图像测速技术(PIV),展现抗滑桩加固均质边坡内部位移场演化及其滑移破坏过程,以揭示锚固长度对均质边坡滑动面和抗滑能力的影响机理。研究结果表明:抗滑桩加固边坡的滑动面深度随抗滑桩锚固长度的增加而加深,同时抗滑能力得到提高,但当锚固长度超过其最优锚固长度后滑动面变浅,表现为越顶破坏,使得抗滑桩抗滑能力大幅降低;当抗滑桩锚固长度达到其最优锚固长度时,出现靠近桩底端位置和越顶的两个深浅不一的滑动面;随着锚固长度的增加,抗滑桩上部外侧受拉区减小,而下部内侧受拉区增大,最大弯矩位置均在距桩顶约0.4倍桩长处,而当锚固长度超过其最优锚固长度后,则出现下部外侧受拉而中上部内侧受拉,其最大弯矩位置在距桩顶约0.35倍桩长处;抗滑桩最优锚固长度与岩性、桩间距、桩体刚度等因素相关,在实际工程设计中应考虑这些因素以确定优化的锚固长度。     

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     

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