含水岩石动态抗压强度与微观机制

通过选取云南迪庆某地区红砂岩进行不同含水状态和不同脉冲强度下的SHPB试验和SEM试验,分别从宏观和微观角度研究含水岩石的动态强度特性及其破坏机制。结果表明:静态或动态单轴压缩时,随着含水率的升高,岩石的强度均降低;根据SHPB试验中的应力-应变全过程曲线,含水试样体积压缩变形明显,具有较高的峰值应变,峰后有应变软化特征,而干燥试样具有较高的峰值强度,峰后应力迅速跌落;根据各试样的动态抗压强度变化曲线,相同脉冲强度下试样的抗压强度随含水率的增加而降低,而相同含水状态时的抗压强度随脉冲强度的增加而增大;根据SEM图像,饱水试样颗粒结构疏松而干燥试样颗粒结构致密,冲击破坏机制饱水试样以初始微裂纹破裂和矿物边界或物相边界破裂为主,破坏时的动态抗压强度较低,而干燥试样还包括矿物颗粒直接剪断破裂,因此破坏强度较高。     

双孔洞裂隙砂岩裂纹扩展特征试验与颗粒流模拟

基于尺寸为80mm×160mm×30mm的双孔洞裂隙长方体砂岩试样单轴压缩试验结果,分析了双孔洞裂隙砂岩裂纹扩展特征,建立了双孔洞裂隙砂岩宏观应力-应变曲线与裂纹扩展过程的关系.利用颗粒流模拟程序,基于试验结果进行细观参数校准,进一步研究了裂隙倾角对双孔洞裂隙试样力学参数及裂纹扩展特征的影响.与完整砂岩试样相比,双孔洞裂隙试样力学参数显著降低,但降低程度与裂隙倾角密切相关.随着裂隙倾角的增大,双孔洞裂隙试样峰值强度先减小后增大,弹性模量呈逐渐增加的趋势,而峰值应变呈非线性变化.完整试样呈轴向劈裂脆性破坏,而双孔洞裂隙试样首先在孔洞上下边缘及裂隙的尖端附近萌生初始裂纹,裂纹的扩展与贯通导致了试样最终失稳破坏.最后探讨了双孔洞裂隙试样裂纹扩展细观机制:首先在裂隙尖端附近和孔洞边缘形成应力集中区,应力提高导致颗粒间黏结断裂,产生微裂纹;在应力集中区转移过程中不断产生新的微裂纹,微裂纹的汇集形成宏观裂纹.     

饱水与干燥状态下横观各向同性板岩蠕变特性

为研究水对横观各向同性板岩蠕变特性的影响,采用RYL-600微机控制岩石流变仪,以分级增量加载方式对饱水与干燥状态下具有横观各向同性特性的板岩进行蠕变试验.试验结果表明:饱水板岩试样和干燥板岩试样在蠕变试验中均出现瞬时弹性变形阶段、初始蠕变阶段、等速蠕变阶段及短暂的加速蠕变阶段.在相同加载条件下,饱水板岩试样的瞬时弹性模量小于干燥板岩试样的瞬时弹性模量.低应力状态下,饱水及干燥试样的蠕变速率都稳定,且相差不大;在高应力状态下,两种情况的蠕变速率都随载荷的增加而快速增长,且相差较大.饱水试样的破坏应力小于干燥试样的破坏应力,且随着层理角的增加都呈U形分布.     

碎裂板岩不同含水状态下蠕变特性试验

为了认识不同含水状态下碎裂板岩的蠕变特性,利用Instron全数控电液伺服力学试验机对贵州黔东南地区隧道洞口的碎裂板岩进行单轴压缩蠕变试验,研究其自然风干、不完全饱和和饱和试样的蠕变特性。实验研究结果表明：（1）碎裂板岩蠕变过程主要包括衰减蠕变和稳态蠕变过程,超过一定应力后,在极短的时间内破坏,因此可由广义开尔文模型描述其蠕变过程;（2）自然风干试样蠕变破坏应力为66.2 MPa,为自然风干试样瞬时单轴抗压强度的71.7%,不完全饱和试样蠕变破坏应力为56.1 MPa,饱和试样蠕变破坏应力为38.2 MPa;（3）不完全饱和试样的最大蠕变应变为自然风干试样的2.7倍,而饱和试样的最大蠕变应变值是自然风干试样的4.3倍。     

石膏试样分级加载流变力学特性试验及应用

采用SAW-2000微机控制电液伺服岩石力学试验机,对自然和水饱和石膏试样开展了分级加载流变力学试验.根据流变力学试验结果,采用FLAC3D(fast lagrangian analysis of continua 3 dimension)模拟了水饱和石膏矿采空区顶板和地表沉降的蠕变规律.研究结果表明:自然和水饱和石膏试样的轴向应变和横向应变的大小取决于分级加载应力水平,且随分级加载应力水平的提高而逐渐增大;水饱和石膏试样的长期强度为其自然的长期强度的55%;自然和水饱和石膏试样的横向应变增量与轴向应变增量的比值随加载应力水平的提高而增加;石膏试样的流变力学特性曲线符合粘弹性流变特征,属于蠕变韧性破坏;石膏矿在淹井或闭坑后的半年至一年期间,是矿柱加速蠕变阶段且伴随矿柱的损伤演化直至破坏,是引发地表沉降的活跃期.     

水压轴压长期共同作用下深部矿井灰岩蠕变特性试验研究*

借助于高精度微机控制多通道水压轴压联合作用岩石流变试验系统,对灰岩进行水环境中的压缩流变试验,采用相同水围压力和不同轴向压力连续加载方式,开展水压轴压共同作用下灰岩蠕变特性的初步研究。试验结果表明:相同水压环境中,轴向变形量随着应力水平的增加而增大,且变形速率随着时间的增加而减小;岩石蠕变破坏模式与轴向应力有关,可能存在某一应力阈值,低于该轴向应力阈值时岩石为张拉破坏,超过该阈值时岩石呈剪切破坏;初步分析了水压影响岩石蠕变的机制,可为研究水压环境中地下工程的长期稳定性提供参考依据。     

直剪条件下单裂隙岩体力学行为数值模拟试验

为探究单裂隙岩体剪切过程中的力学行为,利用颗粒流程序研究裂隙倾角和法向应力对单裂隙岩体力学行为的影响,分别从岩体力学性能、破坏模式及细观力学特征3方面对非贯通单裂隙岩体试样直剪试验中的力学行为进行数值模拟。研究结果表明:(1)法向应力越大,剪应力峰值及对应剪切位移越大,裂隙倾角为60°时,剪切应力峰值最低,与完整试样相比,裂隙试样黏聚力下降最为明显;(2)剪应力曲线由低法向应力(小于5 MPa)时的"光滑"状转变为高法向应力(大于15MPa)时的"台阶"状,主要是高法向应力时岩体内微裂纹产生的速度快慢相间,致使裂纹扩展具有明显的阶段性;(3)法向应力越大,试样内微裂纹数目越多,剪切裂纹数目逐步增加,但仍以张性裂纹为主,大部分微裂纹在剪应力峰后段形成,单裂隙岩体的破坏主要是由张性裂纹汇聚贯通而形成的宏观拉破坏;(4)单裂隙岩体的剪切破坏是颗粒间最大接触力位置的转移与微裂纹交汇贯通的结果,"压致拉"作用力在剪切过程中作用明显。     

甘孜地区高填方回填土三轴试验研究

对甘孜地区非饱和高填方回填土(灰岩碎石土、全风化变质砂岩、粉质粘土)进行三轴不固结不排水试验研究,对不同压实度、不同含水量、不同围压下试样的破坏形态、破坏点轴向应变、应力应变关系、残余强度、抗剪强度指标等进行对比分析。试验结果表明:试样破坏形式与含水率和围压有关,含水率越高,围压越大越容易出现鼓胀破坏、越不容易出现剪切面;破坏点轴向应变与含水率和围压大小有关;分析三种土的粘聚力和内摩擦角随含水率的变化趋势发现甘孜地区粉质粘土遇水稳定性最差,灰岩碎石土遇水稳定性最好。     

不同高径比石膏试样破坏特性及其能量耗散

采用RMT-150B岩石力学试验机,对七种不同高径比的石膏试样进行了单轴压缩试验,分析其力学特性及其破坏特征.根据单轴压缩力学试验结果,利用能量耗散理论,分析其能量耗散特性.研究结果表明:随轴压应力的增加,石膏试样内部微裂隙先闭合,而后在其尖端产生了新裂隙;新裂隙随轴压应力的增加而逐渐地扩展、贯通、形成破裂面,最终发生剪切滑移破坏;石膏试样的体积应变随轴压应力的增大,经历了先压缩后增加,最后急剧膨胀,表现出明显的非线性变形;石膏试样的峰值应力、弹性模量随高径比的减小而增大;轴向应变和横向应变随高径比的减小而减小;变形模量与高径比之间的关系不明确,不能用其表征石膏试样的变形特性;高径比越大的石膏试样受压后容易发生剪切破坏,破坏时吸收的能量增量越快,属于脆性破坏,而高径比越小的石膏试样则发生压酥破坏,属于塑性破坏.     

库水升降作用下高陡岩质边坡稳定性分析研究

为有效分析库水升降作用下库岸边坡稳定性,以三山岛金矿的仓上露天坑尾矿库高陡岩质边坡为依托背景,选取库岸边坡岩样分别进行自然状态下和不同“饱水-失水”循环次数下的单轴抗拉强度试验、单轴抗压强度试验。考虑“饱水-失水”循环对岩石的损伤影响,在广义Hoek-Brown强度准则的基础上,引入了“饱水-失水”循环作用后岩石单轴抗压强度累积损伤率,对Hoek-Brown强度准则进行了改进,确定了库岸边坡的岩体力学参数。以此为基础,利用FLAC3D数值分析软件对库岸边坡进行稳定性分析研究。结果表明：库水升降作用对库岸边坡岩体物理力学性质的损伤作用十分明显,随库水升降循环次数的增多,库岸边坡岩体力学参数不断劣化。数值模拟监测情况与实际工程的位移监测数据对比分析整体误差较小,证明岩体力学参数计算的可靠性,以此为基础计算得库岸边坡将在经历30次“饱水-失水”循环作用后最终破坏失稳。其所得结论能够为类似边坡工程的稳定性分析提供参考与指导。     

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