压剪作用下节理倾角对类岩石材料破坏模式的影响

采用在水泥砂浆初凝前预埋云母片的方法制作含不同分布形态的充填节理试件,并对试件进行压剪试验,探究压剪复合作用下节理倾角对岩体破坏模式的影响及节理岩体破坏机理。应用RFPA2D有限元程序建立相应的数值模型,进行数值计算。试验和数值模拟结果表明:节理倾角对试件初始破坏时翼裂纹的产生位置和最终破坏形态都有显著影响;不同倾角的节理在不同程度上弱化了类岩石试件的抗剪强度,节理倾角为15°时抗剪强度最小,而60°时最大;节理倾角小于45°时,试件破坏所需剪切位移小于无节理试件破坏时的剪切位移,节理倾角大于或等于45°时大于无节理试件破坏时的剪切位移。     

断续节理对岩体力学性能的影响

采用颗粒流数值模拟程序,建立不同节理状态的岩石试样模型,对其进行双轴试验模拟,从岩桥长度、节理长度和倾角三个方面对断续节理影响下的岩体破裂形式和力学性质进行了数值模拟分析.岩桥的破裂方式为翼裂纹扩展下的拉剪复合破坏,模型破裂大致经历了翼裂纹的扩展、次生裂纹的延伸以及岩桥的贯通三个过程,而且表现出明显的蠕变特性以及延性破坏.岩桥长度的变化对峰值强度和弹性模量影响较小;相比岩桥长度,节理岩样的力学特性对节理长度更加敏感.对于不同的节理倾角,岩石试件表现出不同的初始破裂形式,0°倾角岩样的破裂方式为翼裂纹的扩展和次生裂纹的延伸,中间岩桥没有被贯通,15°倾角岩样的初裂强度和峰值强度最大.     

节理特性对花岗岩起裂应力和损伤应力影响规律颗粒流模拟

节理花岗岩起裂应力、损伤应力的研究对认识其渐进破坏过程和脆性破坏机制具有重要意义.利用细观颗粒流软件模拟了不同长度、倾角的单节理花岗岩单轴压缩试验,并通过监测微裂纹确定其起裂应力和损伤应力,研究了节理长度、倾角对起裂应力和损伤应力影响规律.结果表明:当节理方向与加载方向夹角α一定时,随节理长度L增加,起裂应力和损伤应力逐渐递减,其中α为30°~60°时,递减幅度最大;而当L一定时,随α增加,起裂应力、损伤应力先递减再递增,当α为90°时,起裂应力略有下降;当α为45°时,起裂应力最小,而当α为30°或45°时,损伤应力最小.单节理花岗岩起裂应力与峰值应力比值介于29.1%~45.04%,大部分大于完整花岗岩,而其损伤应力对节理长度、倾角变化的敏感度要大于峰值应力,其值介于72.84%~83.25%,大于完整花岗岩.节理花岗岩起裂应力和损伤应力大小与其破坏模式有关,当主破坏面裂纹起裂和扩展始于节理尖端而沿节理方向时,起裂应力和损伤应力最小.     

单轴压缩荷载下不同倾角三维通透裂隙扩展机理研究

采用红砂岩制作分别含有不同倾角三维通透裂隙的圆柱体标准试件,进行单轴压缩试验,并结合实时监控和数值模拟的方法对其断裂破坏机制进行系统分析。试验发现:单轴压缩荷载下,不同倾角预制裂隙主要以翼裂纹和反翼裂纹两种模式扩展,扩展路径均在一定程度上偏离最大主应力方向,当预制裂隙倾角小于等于45°时,裂隙扩展以反翼裂纹为主,且扩展路径偏离程度随预制裂隙倾角的增大而增加,当预制裂隙倾角大于45°时,裂隙扩展以翼裂纹为主,且扩展路径偏离程度随预制裂隙倾角的增大而降低;含裂隙试件的起裂角度随预制裂隙倾角的增大而减小,起裂强度,峰值强度以及弹性模量均随预制裂隙倾角的增大而增大。数值模拟结果发现,翼裂纹的萌生与扩展主要由拉剪应力主导,反翼裂纹的萌生与扩展主要由压剪应力主导,拉应力集中区域随着预制裂隙倾角的增大而逐渐缩小。     

含预制裂隙花岗岩破坏的细观多相颗粒流模拟

基于断裂力学理论,分析了单轴压缩条件下,裂隙倾角对岩石裂纹起裂的影响.根据花岗岩矿物组分,建立了包含长石、石英和云母三相结构的细观颗粒流模型,模拟不同裂隙倾角下花岗岩的单轴压缩破坏过程,得到了花岗岩裂纹起裂、强度、应力应变、破坏形态等力学特征.研究结果表明:岩石试样优势起裂角为24°～30°,定向裂隙对裂纹起裂具有导向、促进作用;裂隙花岗岩的起裂应力和峰值强度随裂隙倾角的增大均表现为先减小后增大的变化趋势,当裂隙倾角为45°～60°时,岩石试件强度最低;裂隙花岗岩试样的压缩变形主要为裂隙面的变形,预制裂隙与新生裂隙的连接与贯通形成的宏观破裂面导致岩石破坏;花岗岩矿物组分比例对裂隙花岗岩强度有一定影响.     

节理倾角对岩体破坏特性影响的单由压缩数值试验

岩体中的节理通常会对岩体的破坏特性产生决定性的影响,本文通过对单轴压缩试验条件下含不同倾角节理的岩体试样破坏过程的数值试验,发现由于岩石材料的非均匀性,不合节理时岩石试样的宏观破坏主裂纹位置和方向不确定,具有一定的随机性,而且峰值强度较高;含节理的岩体宏观破坏时主裂纹明显受节理的影响,除节理倾角0°情况外,主裂纹均与节理的上下端相连;含节理岩体的峰值强度均低于不合节理的岩体,并且节理倾角60°以下时岩体峰值强度较低,而60°以上时峰值强度开始明显升高,90°时甚至接近不含节理的岩体.     

基于PFC 2D的含节理岩体单轴压缩数值模拟

基于颗粒流方法模拟含节理岩体的单轴压缩破坏过程,并对不同节理倾角的岩体进行单轴压缩数值模拟,研究不同节理倾角岩体的裂纹扩展路径、破坏形式以及强度变化规律。结果表明:(1)在单轴压缩破坏过程中,岩体节理倾角不同,裂纹扩展与最终破坏形态不同,但破坏过程基本一致;(2)当节理倾角从0°到90°的变化过程中,抗压强度随节理倾角的增大先减小后增加,总体呈"U"型分布规律,并在倾角为60°时达最小值。     

预制平行双节理类岩石材料板动态破坏试验研究

大型土木工程选址通常会遇到较复杂的地质结构.在工程建设或运营期间,往往受到地震、爆破等动态荷载作用,动载下其基础坐落的岩体内蕴含的节理裂隙会被激活发展,严重威胁着大型岩体工程的安全,因此,研究含节理岩体在动荷载作用下裂纹的起裂及扩展机理十分必要.试验基于断裂力学理论,取含平行双节理的类岩体材料作为研究对象,以节理角度作为变量,制作水泥砂浆试块,利用分离式霍普金森杆(SHPB)加载系统和数字图像相关(DIC)技术,动态捕捉节理的起始扩展及动态传播过程,分析其破坏形态、位移场和应力场,结果表明:①随着节理角度从0°至90°逐渐变化,样品强度呈现出先增大再减小,最后再增大的变化规律;②不同角度双裂纹试样均呈现X型主裂纹分布破坏,试样中心部位出现应变集中,岩桥连通破坏.岩桥破坏类型主要有两种,一种为两条节理尖端斜对角线相连的Z型破坏,另一种为口字形破坏.此外,高加载率会改变Z型岩桥破坏的连通位置;③同等加载条件下,0°节理试样裂纹尖端应力较小;15°～45°节理试样裂纹尖端应力略高,呈现出随加载率先增大后减小的形态;60°节理试样组受压明显导致节理面摩擦增大,使得Ⅱ型应力强度因子KⅡ持续增大;75°～90°试样组应力场由于相对加载方向垂直度较高,导致KⅡ相对较小,变化幅度也较小,破坏形态基本对称,不同裂纹尖端的KⅡ差值也较小.试验结果反映了节理岩体在动态荷载下的扩展机理,为工程建设及地质灾害防治等领域提供了一定的理论支撑.     

基于颗粒形状的节理花岗岩力学性能颗粒流模拟研究

以齐热哈塔尔水电站的片麻花岗岩为研究背景,基于颗粒流数值理论,采用离散单元法,运用其内置的Fish语言建立由不同形状的clump单元组成的片麻花岗岩数值模型。通过预制7种不同倾角的光滑节理模型来分析片麻花岗岩节理方向性下的力学响应与损伤机制。研究结果表明:不同倾角下节理岩体的破坏模式为三种类型:翼裂纹的张拉模式、剪切模式、拉剪复合耦合模式,倾角为60°岩样相比于其余倾角强度最低,拉应力引起的裂纹起裂是导致各种宏观破坏的主要诱因,研究成果可为实际工程提供指导意义。     

裂纹岩体贯通路径的有限元搜索

裂隙岩体在荷载作用下导致其内部裂纹的相互贯通,从而在裂纹尖端形成较大的塑性破坏区域,岩体工程的失稳大多是由于其内部节理、裂隙等缺陷发展导致的,应用断裂力学的方法,可以追踪岩体中节理裂隙的起裂、扩展至相互贯通使岩体局部破坏的过程,从而揭示岩体失稳的渐进破坏机制.应用有限元方法中的奇异单元模拟了岩体中不同倾角的压剪裂纹的破坏问题,根据不同倾角裂纹的力学机理分析了其受力差异,依据最短塑性区距离判据分析了相近裂尖的扩展距离,得出了不同倾角的两共线裂纹的破裂角及相近裂尖破坏后岩桥之间的有效距离.     

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.     

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.     

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.