降雨渗流对堆积型滑坡稳定性影响的数值模拟 －以贵州大榕滑坡为例

降雨是堆积型滑坡失稳破坏的主要诱因之一,滑坡的失稳和破坏与雨水渗流紧密相关。选取贵州省岑巩县大榕滑坡为研究对象,大榕滑坡为典型的古滑坡堆积区失稳,通过详细分析该堆积型滑坡形态特征、地层岩性、物质结构及变形特征,根据工程水文地质条件建立数值计算模型,利用饱和-非饱和渗流有限元模拟降雨入渗时滑坡堆积体的瞬态渗流场,将计算得到的瞬态孔隙水压力和基质吸力对非饱和土抗剪强度的影响用于滑坡极限平衡分析,根据渗流场和应力场数值耦合分析不同降雨雨型、强度、历时对滑坡稳定性的影响。研究表明:降雨是滑坡持续变形并失稳的诱发原因,与降雨类型相比降雨强度对滑坡稳定性影响较大;滑坡稳定性在降雨结束后延滞一段时间达到最小,此时对滑坡的稳定性最不利,随后稳定性逐渐上升。     

不同降雨过程特征下的库区滑坡稳定性

降雨是滑坡的主要诱发因素之一.根据降雨强度随着降雨历时的变化特征划分了五种降雨过程.以澜沧江某水电站库区一典型土质滑坡为例,模拟滑坡体在不同工况下的渗流场,分析降雨过程对库区滑坡稳定性的影响.结果表明：在库水位不变的情况下,五种降雨过程对滑坡稳定性的影响由大到小的顺序为递增型、先强后弱型、先弱后强型、稳定型、递减型.在降雨过程不变的情况下,随着库水位的上升,滑坡稳定性会先减小再增大.水库蓄水前期及递增型降雨过程,滑坡处于最危险状态.该研究为库区滑坡稳定性评价提供了依据.     

三峡水库年周期调度内降雨模式对白水河滑坡稳定性影响研究

通过将三峡库区水位年调度周期概化为6个阶段,以白水河滑坡为研究对象,选取对滑坡最不利的3个阶段,开展了不同降雨开始时间及不同降雨形式对滑坡稳定性的影响研究.结果表明:在AB和DE阶段,降雨发生时间越晚,即相应库水位越低时,对于滑坡稳定性越不利;在AB、BC和DE阶段,白水河滑坡稳定性整体处于较低水平,滑坡稳定性系数在递增型和中间小型的降雨时较小,在递减型和中间大型的降雨时较大.研究结果可以为白水河及类似滑坡稳定分析及预测提供一些依据.     

降雨及坡体组成对堆积型边坡稳定性的试验研究

滑坡灾害是常见地质灾害之一,人类工程数量和规模的发展,致使堆积体滑坡灾害在滑坡灾害中的比重不断增大,如何保障堆积体稳定性值得研究。本文通过试验测试的方法,从堆积体材料的组成出发,对比分析不同降雨强度、不同含土率、不同骨料比例对堆积体稳定性的综合影响。试验结果表明：（1）堆积体的含土率对滑坡规模影响较大;（2）降雨强度与堆积体破坏程度成正比关系;（3）堆积体的临界坡度越大其稳定性越好。在工程实际中,为确保人工堆积体边坡具有较好的稳定性,应合理规划堆积体的材料组成,降雨期间应着重监测含土率较大、临界坡度较小的堆积型边坡。     

强降雨诱发平缓滑坡复活变形与稳定性演化分析

平缓滑坡因地形坡度小易受强降雨影响而发生变形破坏.为深入研究强降雨对滑坡复活变形及稳定性的影响,以湖北省秭归县土地岭滑坡为例,进行强降雨条件下的滑坡渗流-应力耦合模拟,分析不同降雨条件下的滑坡复活变形过程中的孔隙水压力、位移场变化和稳定性演化.研究表明,平缓的土地岭滑坡的阶跃变形与集中强降雨密切相关,降雨导致滑坡体内孔隙水压力从后部到前部逐渐增加,前部响应最快;滑坡稳定性系数随降雨过程逐渐降低,在24 h内降幅最显著.这对强降雨引发滑坡的变形机制与预警具有一定的参考价值.     

降雨型滑坡安全预警模型研究进展

极端天气条件下,滑坡灾害发生频次更高、影响范围更广、社会影响更大。监测预警是减缓地质灾害风险有效措施之一。降雨是影响边坡稳定性的重要因素,降雨型滑坡安全预警系统的研究方面取得了不少成果。对适用于不同岩土类型的滑坡安全预警模型进行分类总结,对未来的研究工作具有一定的指导作用。对研究成果进行归纳分析发现:滑坡安全预警模型逐渐转向对特殊岩土类型边坡的研究;比例尺较大的县乡级的区域降雨滑坡预警更适合我国的国情;目前降雨型滑坡模拟物理试验及数值模拟试验研究仍显不足,降雨型滑坡安全预警模型在实际预警工作中还存在误差。为提高坡体滑坡监测和安全预警效果,未来应大力开展基于卫星遥控遥测技术的滑坡监测与预警预报系统研发利用,加强对各影响边坡稳定性因素的相互作用研究。     

暴雨及久雨作用下东岭信滑坡堆积体的渗流特性及稳定性分析

暴雨和久雨是影响滑坡稳定性的重要因素.选取东岭信滑坡堆积体典型剖面,研究其在降雨条件下的稳定性演化机制.基于非饱和渗流基本理论研究了相同雨量、不同雨型下堆积体的渗流特性,并基于渗流场计算结果采用极限平衡法计算了安全系数.根据计算结果,从降雨过程中和降雨后两个角度分析了堆积体内部渗流场与稳定性对不同降雨条件的响应规律.结果表明,暴雨较久雨对堆积体渗流场的影响更大,并表现出强烈滞后性;而久雨较暴雨对堆积体稳定性影响更大,且表现出较弱滞后性;暴雨易在降雨结束后造成滑坡,而久雨更有可能在降雨过程中造成滑坡.     

礼县烂山滑坡特征及地震-降雨耦合作用下稳定性分析

在对礼县烂山滑坡进行工程地质调查的基础上,结合区域环境研究滑坡的主要特征和稳定性影响因素,得出其高陡的地形、不稳定的岩土体、已有的变形破坏以及研究区的降雨、地震和人类活动等因素造成该滑坡的发展趋势为稳定性差,危险性大。结合Geostudio软件对烂山滑坡分别处于天然、降雨、地震、地震降雨耦合四种状态下的14种工况进行数值模拟,定量分析了降雨强度、降雨持时、地震动时程三个参数对烂山滑坡非饱和土渗流、地震动力响应以及稳定性的影响,结果表明地震与降雨耦合作用对滑坡的稳定性有累计折减效应,地震对烂山滑坡的稳定性起控制性作用,降雨起到促进作用使得滑坡更容易发生。     

水动力型滑坡堆积体渗流稳定性数值分析

汛期强降雨对水动力型滑坡堆积体渗流稳定性有着重要影响.本文结合三板溪水电站库区东岭信滑坡堆积体工程,揭示了正常蓄水位条件下降雨入渗对深厚滑坡堆积体孔隙水压力变化的影响机理,开展了不同工况下滑坡堆积体渗流稳定性数值分析.数值计算结果表明,滑坡堆积体前缘局部稳定性主要受库水位和降雨入渗联合作用;滑坡堆积体中后部稳定性主要受降雨入渗影响,受库水位影响不明显,因此,汛期强降雨是影响深厚滑坡堆积体整体稳定性的关键因素,设置排水洞可有效提高东岭信滑坡堆积体整体稳定性.研究结果可为类似水动力型堆积体滑坡灾害治理与防范提供参考.     

某水库滑坡在降雨作用下的稳定性模拟分析

水库型滑坡主要受库水位升降变化而发生变形,因此对水库滑坡的研究主要集中在库水变动影响下的滑坡变形机理及稳定性分析方面.然而通过对三峡库区滑坡调查发现,有一类水库滑坡变形主要受降雨影响,而研究这类滑坡在降雨和库水共同作用下的变形及稳定性同样具有重要意义.本文以三峡库区某水库滑坡为例,在详细调查该滑坡地质条件及变形发展过程基础上,运用数值模拟方法对其渗流场及稳定性进行了定量分析.结果表明,该滑坡由于特殊的地形条件,其变形主要受降雨影响,受库水位升降影响较小.     

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