水泥混凝土路面接缝传荷能力模型试验研究

为研究正常使用状态下水泥混凝土路面接缝传力杆的传荷性能影响因素及其衰减规律,进行了3组10块带接缝水泥混凝土路面板的室内疲劳试验。试件分别采用不同的传力杆直径、长度和混凝土板厚度,考虑了3种不同因素对传荷能力的影响,后续建立的ANSYS有限元模型也对试验结果进行了验证。通过分析不同工况下路面板接缝两侧的弯沉值及传荷系数表明:水泥混凝土路面板的传荷能力在最初加载的7万次过程中衰减明显,之后衰减缓慢;传力杆直径、长度及混凝土板厚度的增加,能够提高接缝的传荷效率,但十分有限。     

设传力杆的刚性道面板接缝力学性能研究

基于Winkler地基模型,建立考虑传力杆与混凝土接触的机场刚性道面三维有限元模型。采用单因素分析法,讨论了五种不同水平的道面板厚度、传力杆直径、间距及地基刚度各因素对接缝处水泥混凝土道面板应力、接缝传荷能力、传力杆与道面板间界面拉应力以及传力杆剪应力的影响。结果表明:同一荷载条件下,混凝土板厚由250 mm增大到450 mm,板底水平弯拉应力降低68.4%,传荷系数降低8.8%,界面拉应力降低52.4%,传力杆剪应力降低28.2%,影响显著,而传力杆间距和直径的影响次之。此外,地基刚度参数对传力杆剪应力的影响很小,可以忽略。同时,基于相似理论,设计接缝设传力杆的道面板室内模型试验,并将实测结果与数值模拟结果进行比较,结果表明两者的位移传荷效率与传力杆内力分布规律基本吻合。     

考虑机场道面结构损伤的传力杆设计修正方法

为了减少机场道面结构损伤对接缝传荷性能的影响,基于相似理论,分别对传力杆松动和板底脱空2种损伤形式下,道面板受荷性能进行了模型试验研究。同时,采用ABAQUS有限元软件建立了接缝设传力杆的机场水泥混凝土道面结构三维有限元模型,对道面结构损伤模型试验进行了模拟。进一步,针对不同尺寸的传力杆松动、板中脱空和板角脱空,采用有限元方法分析了道面板在7种水平的传力杆长度、直径和间距下的传荷性能,以及2种结构损伤形式下传力杆参数对传荷性能的敏感性。在此基础上,以接缝剪力传递系数、关键传力杆分配系数、板底弯拉应力幅值以及界面应力为控制指标,分别分析了当道面板存在传力杆松动和板底脱空损伤时,相对于未损伤工况,提高传力杆参数尺寸对上述指标增长率的改善程度,进而提出了考虑道面结构损伤的传力杆参数设计范围,并与《民用机场水泥混凝土道面设计规范》(MN/T 5004—2010)(简称规范,下同)进行比较。结果表明:位移传荷系数L_(TEδ)随脱空尺寸的增加先减小后增大,随着松动尺寸的增大逐渐降低,且2种结构损伤模型试验结果与有限元模拟规律一致;传力杆直径对松动损伤最敏感,而传力杆间距对板底脱空的敏感性最大;随着传力杆直径和间距的增加,控制指标增长率均呈现先减小后小幅增加并趋于稳定的趋势,说明当考虑道面结构损伤时,增加传力杆直径和减小其间距只能在一定范围内改善传荷性能。因此,对应不同板厚,考虑松动损伤的传力杆直径建议值为规范值的110%～130%,而考虑板底脱空损伤时传力杆间距建议值为规范最大值的70%～98%。     

接缝设传力杆水泥混凝土面层结构力学分析

建立接缝无传力杆及设传力杆时水泥混凝土面层结构的三维有限元模型,运用数值分析方法,分析接缝处水泥混凝土面层的荷载应力、弯沉值和弯沉差,研究了地基模量、传力杆直径对荷载应力及弯沉差的影响规律,并对条件相同的计算结果进行了对比分析.结果表明:计算点的主应力、剪应力、弯沉值和弯沉差随着传力杆直径的增加而呈现减小趋势;当传力杆直径大于35mm时,传力杆直径的增加对降低水泥混凝土面层内计算点的应力值效果已不明显;接缝设传力杆时水泥混凝土面层计算点荷载应力和弯沉差明显小于无传力杆时相应的计算结果;当地基模量不大于800MPa时,建议基于剪应力去估计接缝传荷效率;当地基模量大于800MPa时,建议基于弯沉值或主应力去估计接缝传荷效率.     

水泥混凝土路面传力杆应力分析力学模型

应用三维有限元模型分析水泥混凝土路面中传力杆与水泥混凝土的接触状况,并基于弯曲刚度等效原则将传力杆和水泥混凝土面层系统简化为双层梁结构.计算结果表明,弹性地基上双层梁结构可很好地描述水泥混凝土路面的挠曲效应,而接缝处的双层梁相对位移、转角、以及挤压应力合力与三维有限元解的差异,只需对双层梁层间竖向反应模量进行修正即可;随后,总结归纳了相对位移、转角及挤压应力合力修正系数的回归式,讨论给出了接缝传力杆的抗剪刚度与抗弯刚度的计算式,并指出传力杆的传递弯矩的能力很小可忽略.最后,计算分析了梁端部作用集中荷载时,有基层的地基梁接缝传荷问题,指出在接缝抗剪刚度相同条件下,基层存在可使接缝两侧挠度比增大,接缝传递的剪力减小.     

刚性路面接缝传力杆挠度解析计算

采用能量变分原理推导了双参数地基梁平衡微分方程以及相应的边界条件,进而求得基于双参数地基梁理论的传力杆挠度解析通解.通过算例与传统单参数地基梁理论计算结果进行了比较,表明与单参数地基相比,双参数地基更能真实模拟刚性路面中混凝土对接缝传力杆的支承和约束,单参数地基是双参数地基的特例,传力杆受力分析时,剪切力和弯矩对传力杆挠度的影响同等重要,传力杆受力分析中,杆端弯矩和剪切力应同时考虑,传力杆宜采用弯剪梁模型.     

水泥混凝土路面传力杆布设方式仿真模拟

为优化水泥混凝土路面传力杆布设间距设计,以有限元理论为基础,依据中国水泥混凝土路面设计规范设置模型参数,建立了文克勒地基上考虑不利荷载作用时的单层面板3D有限元模型。基于模型得到2种传力杆布设方式情况下面板的力学响应值,计算出等间距时接缝传荷系数(LTE)对间距的关系式、LTE和板最大位移,并分析轮迹集中布设传力杆的作用效果。研究结果表明:等间距布设传力杆时,在LTE与传力杆间距计算模型下,间距在450~1 800mm之间变化时,LTE变化小;轮迹集中布设传力杆将LTE平均提高3.015%,且传力杆根数越少提高值越大;LTE相等时,轮迹集中可将每条接缝处传力杆根数平均减小1根,与均布相比,即使减少1根传力杆时仍对板位移产生有利影响,且具有良好的经济效益。     

机场刚性道面接缝传荷能力的评价

基于ABAQUS有限元软件,按照"贡献面积"刚度分配原则,通过在相邻混凝土板侧面的对应结点设置弹簧单元,建立了考虑接缝传荷能力的机场刚性道面3维有限元分析模型.以重型落锤式弯沉仪(HWD)弯沉测试为基础,针对不同地基强度上的典型道面结构,考虑基层对接缝传荷能力的影响,应用有限元模型,分析了HWD承载板、单轴双轮起落架、双轴双轮起落架和三轴双轮起落架等荷载形式作用在接缝一侧板边中部时道面结构的板边应力和挠度,建立了HWD承载板测试得到的挠度传荷系数与接缝刚度之间的相关关系,以及与不同荷载形式作用的应力折减系数之间的相关关系,成果可用于评价机场刚性道面的接缝传荷能力,以及道面板边应力分析.     

镐头机拆除工况下机场水泥道面的力学行为

以ABAQUS作为分析平台,建立了考虑接缝传荷以及层间接触效应的双板有限元分析模型,可用于模拟镐头机拆除工况下水泥道面的力学行为.针对机场典型拆除工艺参数及道面结构参数,系统分析了镐头机拆除工况下拆除板和周边保留板的变形、拉应力以及层间剪应力的分布特征,揭示了镐头机拆除工况下周边保留板发生破坏的力学机理.分析了面层厚度、接缝传荷能力等参数对拆除时道面力学响应的影响规律,提出了镐头机拆除施工应注意的问题.     

连续配筋水泥混凝土路面的临界荷位

以三板系统模拟连续配筋水泥混凝土路面,计算获得了连续配筋路面的临界荷位.引入接缝混凝土板的传力杆设计理念,确定了连续配筋路面横向裂缝处钢筋的传荷刚度计算公式.同时,以有限元方法建立了CRCP横向裂缝处混凝土的传荷刚度计算公式.裂缝处传荷刚度的确定,为模拟CRCP荷载应力计算提供了关键参数.有限元数值计算表明：三板系统中,当边板长度大于4 m时,边界条件将不对应力计算产生影响.对于双车道路面,计算所得的板宽向最大应力位于左车道外侧车轮板底的轮迹中心处,此时的路面荷位为标准轴载位于路面右边边缘且靠近裂缝边缘,推荐此荷位作为路面承载力检验的核算位置.     

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.     

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.     

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.