库水位循环下岸坡-桥梁桩基相互作用致损机理

库水位循环作用下,库岸边坡岩土体物理力学性质劣化,引起岸坡变形、滑移,将对桥梁基础、桥墩及上部结构产生不同程度损伤,甚至会导致桥梁上部结构落梁、垮塌。针对重庆万州长江二桥库岸边坡失稳致灾问题,采用FEM-SPH(finite element method-smoothed particle hydrodynamics)转换耦合算法建立了岸坡-桥梁三维有限元模型,结合桥位处地质勘测数据模拟了变动水位条件下岸坡变形、滑移、失稳全过程,揭示了岸坡滑移与桥梁桩基相互作用机理,研究了桥墩偏位规律及下部结构失效模式。结果表明：以滑动带有限元网格悉数转换为SPH(smoothed particle hydrodynamics)粒子作为岸坡失稳判据,FEM-SPH转换耦合算法能够更直观、准确地模拟库岸边坡从变形、滑移至失稳全过程;桥位处岸坡将在第16、20次水位升降循环过程中发生失稳破坏;随着岸坡变形、滑移、失稳演化,桥墩偏位呈“缓增-激增”的变化趋势;岸坡发生第2次失稳时,桩基础在土-岩交界面上部发生剪切破坏,破坏面与水平面夹角约为60°。     

龙羊峡近坝库岸滑坡群稳定性分析及预警技术研究

通过对龙羊峡水库蓄水前后边坡地质环境的长期监测,将库岸变形破坏分为完整地层岸坡和滑坡堆积体岸坡的破坏形式,对高库水位条件下的库岸稳定性进行了计算.在计算分析的基础上,对汛限水位抬高至2594m后岸坡的可能的失稳方式、下滑量和潜在失稳边坡涌浪高度进行了评价.结果表明:在2594 m库水位时,可能失稳的为龙西边坡;在2600 m库水位时,可能失稳的为龙西和农场边坡;可以龙西和农场边坡300万m3下滑量作为坝库岸滑坡涌浪高度的评价标准,在此期间确定汛期运行水位时可预留3~4 m的涌浪高度.     

白鹤滩水库初次蓄水对双河段岸坡稳定性的影响预测分析

以白鹤滩库区巧家县双河左岸土质岸坡为研究对象,通过野外详细调查、现场钻孔剪切试验以及SEEP&SLOPE模块耦合分析,针对该岸坡在未来蓄水后的稳定性问题进行预测分析.研究发现:双河左岸土质岸坡主要由残坡积角砾土组成,其对水敏感性较强,饱水后角砾土内聚力降低60.65％,内摩擦角降低40.0％,内聚力受影响程度大于内摩擦角.当水位由当前状态先升至765 m,再升至825 m时,渗流场反应明显,坡体稳定性系数由1.238降至1.098,再降至1.010,降幅先大后小,坡体由稳定状态过渡欠稳定状态后处于失稳临界状态.岸坡土体在库水作用下发生的结构损伤、强度衰减是岸坡稳定性恶化的主要原因,其变形趋势将由蠕滑变形向整体失稳破坏发展;在此过程中,库水的反压作用对于岸坡水下部分具有有利作用,促使岸坡受影响,高程段缩减.     

库水位变化时陡倾软弱顺层岩质滑坡变形机制

研究库水位动态变化时陡倾软弱顺层岩质滑坡的变形机制,为库岸滑坡防治及库水调度提供帮助。以四川省大渡河某水电站开顶滑坡为例,通过野外调查资料、库水位及地面监测数据综合分析,研究滑坡结构及变形破坏特征;建立二维地质模型,利用离散元模拟蓄水前后陡倾顺层岩质滑坡变形响应过程,结合有限元进一步分析库水作用下岸坡稳定性变化规律。研究结果表明,岸坡特殊的地质构造和岩性是控制滑坡产生的主要因素,水库蓄水诱发了滑坡的变形,库水位变化进一步加速了变形进程。当库水位以4.8 m/d、3.84 m/d、1.92 m/d的速率上升时,坡体稳定性呈现先增后减的趋势;当以小于0.5 m/d的速率下降时,岸坡变形不明显,但稳定性急剧降低,极有可能增加变形速率,加剧变形,导致大范围失稳破坏。在水库调度过程中,为避免渗流作用对岸坡稳定性的影响,库水位变化应保持在较小的速率平稳运行。     

水库岸坡地质灾害研究现状与趋势

水库岸坡地质灾害防灾减灾是库区生态环境尤其是地质环境保护的重要科学问题,通过对国内外研究文献的查阅分析并结合多年在三峡库区的研究实践,将水库岸坡地质灾害研究现状概化为水库岸坡稳定性变化、破坏机制、库岸再造预测方法等3方面,系统梳理了每个方面的研究情况。结果发现国内外学者高度重视库水位降落对岸坡稳定性与变形破坏特性的影响机制研究,基于卡秋金法提出了多个库岸再造预测新方法,但在库水位多旋回变动对岸坡作用、库水位周期性浸泡劣化岩土物理力学特性、类土质岸坡等方面研究不多。指出了水库岸坡地质灾害进一步研究应予以高度重视的3个方向,即水库岸坡地质环境效应、类土质岸坡变形与破坏和库岸地质灾害治理新技术新方法。
     

漭街渡大桥边坡稳定性及基础方案的设计与分析

为确定处于超深、超高水库淹没区的漭街渡大桥基础方案,在系统分析桥位岸坡变形失稳机制的基础上,通过对因为水位升降导致不同工况条件下的岸坡稳定性分析评价,对大桥的基础设计提出了原则建议.经漭街渡大桥的工程实例表明:详细准确地分析淹没区桥位岸坡在水位升降变动条件下的稳定性,应成为确定库岸梁桥基础设计的主要依据.     

排架结构码头阶梯形岸坡桩土相互作用模型试验研究

为研究排架结构码头阶梯形岸坡桩土相互作用以及水位变化对桩土作用的影响,进行了大型模型试验模拟。根据试验数据,对排架结构桩周土体的侧向应力分布、排架桩身的受力特性以及水位变化的影响进行了讨论。结果表明:水平荷载作用下,排架各桩桩周土体侧向应力分布相似,呈三角形分布。桩周土体侧向应力随荷载的增加而增大;排架结构对岸坡有遮帘效应,起到一定的抗滑作用;排架桩身弯矩值随荷载的增加逐渐增大,桩身弯矩的大小与桩所处的位置有很大关系;水位越高,桩周土体侧向应力越大,桩身弯矩也越大,码头整体稳定性越差。     

遮帘式板桩码头结构土压力特性模型试验研究

为了研究遮帘式板桩码头结构中土压力的传递机理,采用模型试验分别模拟遮帘式板桩码头结构和单锚式板桩码头结构的开挖过程,分析2种板桩码头结构中不同断面上土压力的变化规律.试验结果表明:从2种板桩码头结构的弯矩分布和水平变形来看,结果与原型结构的变形形式相符;码头开挖后,在拉杆拉力相近的情况下,遮帘式板桩码头结构中前墙水平位移和弯矩小于单锚式板桩码头结构;当前墙上土压力减幅相同时,遮帘式板桩码头结构中前墙水平位移也小于单锚式板桩码头结构.遮帘式板桩码头结构体现了很好的遮帘效果.在远离遮帘桩的位置,2种结构的土压力减幅都很小,可忽略不计.遮帘式板桩结构中,越靠近前墙,断面上的土压力减幅越大.     

水库岸坡地质灾害研究现状与趋势

水库岸坡地质灾害防灾减灾是库区生态环境尤其是地质环境保护的重要科学问题,通过对国内外研究文献的查阅分析并结合多年在三峡库区的研究实践,将水库岸坡地质灾害研究现状概化为水库岸坡稳定性变化、破坏机制、库岸再造预测方法等3方面,系统梳理了每个方面的研究情况。结果发现国内外学者高度重视库水位降落对岸坡稳定性与变形破坏特性的影响机制研究,基于卡秋金法提出了多个库岸再造预测新方法,但在库水位多旋回变动对岸坡作用、库水位周期性浸泡劣化岩土物理力学特性、类土质岸坡等方面研究不多。指出了水库岸坡地质灾害进一步研究应予以高度重视的3个方向,即水库岸坡地质环境效应、类土质岸坡变形与破坏和库岸地质灾害治理新技术新方法。     

水位变化诱发均质黄土库岸失稳试验研究

水库水位变化是影响黄土库岸稳定性的重要因素.以不同坡度的边坡模型为研究对象,定量测试了水位变化过程中边坡不同位置处土体的位移、强度、水头变化趋势,探讨了不同坡度的黄土边坡的失稳形态.试验结果表明:坡外水位上升导致岸坡土体软化,坡体整体沉降加大,坡体变形以浅层滑坡为主;水位下降过程中,坡体后缘出现横向张拉裂缝,坡体前缘逐步滑塌,坡角越大,坍岸现象越严重;水位下降阶段导致的土体抗剪强度下降要明显大于水位上升阶段;水的软化作用导致土体强度降低,沉降变形增大,水位骤降阶段土坡内外的压力差是导致土体发生滑塌的主要原因.     

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-