青藏铁路多年冻土区路基温度场的模拟与预测

在多年冻土区修建铁路站场路基,打破了原来天然地表与外界的热力平衡,地下温度场将重新分布.根据此特征可推断多年冻土的发展演化趋势以及评定路基的稳定状况.结合青藏铁路某段站场路基实际监测数据,利用ANSYS软件对2002年～2030年地下温度场进行有限元数值模拟.模拟计算结果表明:路基下冻土上限发生上移,多年冻土得到了保护;在年平均气温增长0.02 ℃的条件下,试验段内冻土人为上限和未受路基影响的冻土天然上限均逐年下降;同时,路基阳坡、阴坡两侧地下温度场分布特征的差异构成了路基不均匀变形和路面裂缝的潜在威胁.     

青藏高速公路宽幅路基温度场模拟分析

运用ABAQUS及其二次开发平台,建立了多年冻土地区路基温度场有限元分析模型.运用该模型对低等级公路窄幅路基和高等级公路宽幅路基温度场进行对比分析,对宽幅路基融深变化规律进行了研究.结果表明:不同宽度路基温度随时间均呈周期变化,但每年平均温度呈现总体上升的趋势,且在相同的时间条件下,随着宽度的增加,温度不断上升,但增加幅度逐渐降低;路基中心线处融深随宽度的增加呈三阶段上升趋势,路肩处融深随宽度的增加呈直线上升趋势,坡脚处融深随宽度的增加而增加,但变化幅度很小;增加宽幅路基高度可以在一定程度上起到保护冻土的作用,但路基高度增加到一定值后,继续增加高度对提高冻土上限作用不明显.     

多年冻土区高等级公路路基温度场研究

在全球变暖的背景下,利用有限元法对多年冻土区高等级公路路基温度场进行数值模拟研究。分析路基高度分别为2.0,3.0,4.0,5.0和6.0 m时路基高度与路基下方冻土上限的关系,分析路面宽度分别为14.0,16.0,18.0,20.0和24.0 m时路面宽度与路堤内和基底融化夹层面积的关系。研究结果表明:在影响路基下方多年冻土上限和融化夹层面积的各因素(路基高度、边坡坡度和路面宽度)中,路基高度对冻土上限的影响程度最大,路面宽度对路基内和基底融化夹层面积的影响最大;冻土路基在20 a的设计使用年限内合理高度为4.26 m;冻土路基在不采取"冷却地基"措施的情况下,在20 a的设计使用年限内,路面最大宽度为6.0 m;当路面宽度为12 m时,分幅路基的合理间距为35.3 m。     

基于路基顶面温度的多年冻土区沥青路面结构

多年冻土地区路基路面稳定性及耐久性与路基底部多年冻土的存在状态密切相关。采用有限元方法,建立多年冻土地区路基与沥青路面结构温度场模型,分析了结构层厚度、结构组合变化对路基顶面温度的影响;利用灰关联方法,以温度稳定性最差的路面结构为参考,分析了不同路面结构间的关联程度。结果表明：增加路面结构层厚度或在路面结构中设置沥青碎石层、级配碎石层,在高温季节可以有效降低路基顶面温度;级配碎石层厚度与路面结构的温度优劣性相关,小于16cm时ACGR、AGR、ACR这3种沥青路面结构较好,大于16cm时ACGR、ACG、AGR这3种结构较好。研究结果可为多年冻土地区半刚性基层开裂处治及沥青路面结构选择提供参考。     

青藏铁路清水河段多年冻土区站场路基的试验研究

通过对青藏铁路清水河段站场路基的初步试验,获取了地温变形数据,探讨站场路基的冻结和融化过程的规律.实验表明:站场路基下冻土人为上限发生了上移,多年冻土得到了保护,为类似路段多年冻土工程提供借鉴.     

多年冻土路基水-热-力耦合理论模型及数值模拟

在建立多年冻土地区路基非稳态温度场控制方程、水分迁移的有限元控制方程和路基变形场及应力场计算模型的基础上，提出水-热-力耦合模型。以青藏公路唐南段K3393＋950的冻土路基为计算对象，得出了1月份路基温度场、水分场及应力场（变形场）的分布规律：路基温度场内部存在着未冻土核；水分场在温度梯度的作用下有向冻结冰锋线迁移的趋势；在负温条件下，土体的体积含冰量超过临界值时，将产生冻胀现象。研究结果表明，多年冻土地区路基的温度场、水分场及应力场一直处于动态变化中，路基的热状况、水分状况与变化规律及由此引起的应力重分布是引起道路冻害的主要因素。     

高纬度林区多年冻土片块石路基降温效果及变形特征

在边坡滑塌、不均匀沉陷等路基病害极易发生的多年冻土区,片块石路基是一种常见的路基结构,而其在高纬度林区的应用研究还相对较少。本文针对高纬度林区多年冻土体积含冰率高、对温度变化敏感等特征,以高纬度林区某段公路多年冻土片块石路基工程为例,建立冻融循环热力耦合数值模型,分析了片块石路基温度场和应力-应变场的变化规律,研究了路基冻胀融沉的热力学机制。结果表明：高纬度林区多年冻土片块石路基的温度场,在地下2 m内受地表温度影响显著,而地下2 m以下受影响较小,温度稳定在-1.5 ℃。多年冻土片块石路基的变形以融沉为主,在11月达到最大值,为13.5 mm;而冻胀量在4月达到最大值,为7.5 mm。路基融沉主要归因于冻土的融化,而路基冻胀是由于路基结构本身的冻胀变形引起的。因此,在高纬度林区多年冻土路基采用片块石冲压层和填筑层的结构是可行的,对路基下冻土起到良好降温效果的同时,路基的变形量也控制在了规范要求范围内。     

青藏公路冻土路基阴阳坡热效应研究

青藏公路多年冻土路段的阴阳坡现象会引发路基及下伏冻土地基热状况不对称分布,影响长期稳定性.为此,基于实测坡面温度数据,开展不同年平均气温和路基高度条件下冻土路基地温场分布及演化规律的模拟.结果表明,年平均气温-3℃下阴坡冻结指数约为阳坡的2倍,融化指数约为阳坡的0.83倍.路基修筑后,阴坡一侧路基下部人为上限均有一定抬升.此后,在气候变暖及沥青路面强烈吸热效应作用下,路基左右路肩下部人为上限不断下降,其中高填方路基人为上限下降速率相对较快.阴阳坡效应作用下,东西路基下部人为冻土上限呈左高右低的趋势,下伏土体温度同样为左高右低.高填方路基下伏冻土层地温分布的不对称较同期的普通填方路基显著.     

对多年冻土地区几种地温调控措施效果的探讨

本文初步分析、对比了214国道多年冻土段几种地温调控措施的工作效果，结果发现遮阳板护坡、碎石护坡的效果较好，能够有效降低冻土温度、提升冻土上限；保温路基通过大幅度减小保温板下的土体温度年较差也可以提高冻土上限减缝冻土退化速率；纵向通风措施也可以有效降低通风管周围的土体温度；硅藻土护坡措施降温效果偏差、综合对比各种措施的降温效果，本文推荐遮阳板护坡和碎石护坡作为该地区地温调控措施的首选，其次是保温路基和纵向通风管措施，最后是硅藻土护坡。     

青藏铁路低温冻土区片石路基的温度特征

在青藏铁路五道梁低温冻土区进行了片石护道路基新结构和土护道路基结构的实体工程试验,以确定路基修筑对温度场的影响.对测试断面冻融循环的地温监测资料的分析表明,2004年片石路基左右路肩孔冻土上限处,年平均地温分别低于土护道路基相应位置0.12℃和0.14℃,2005年片石路基左右路肩孔分别低于土护道路基相应位置0.65℃和0.03℃,冻土上限以下地温均呈逐年下降趋势.片石护道和土护道路基冻土上限均存在不对称性,但随着时间发展,片石护道路基最大融化深度位置基本接近或超过天然地面,且冷生过程还在继续.该区域的片石护道路基新结构能够有效发挥降低地温、主动保护多年冻土的作用.     

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.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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。     

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.     

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.