光纤光栅传感器对预应力锚索的受力监测

预应力锚索的受力状态监测特别是锚索内应力分布的监测是目前工程领域一大难题。本文提出将准分布式光纤布拉格光栅（FBG）内嵌至锚索材料-钢绞线中心丝的技术,以实现对其受力状态及应力分布进行监测。基于此技术,结合FBG监测原理和锚索锚固理论,以锚索锚固长度、FBG布设位置及数量为主要变化参数,设计了FBG自感知钢绞线材料并将其浇筑于钢管内作为锚索模型试件;并对FBG自感知钢绞线材料进行张拉标定试验和钢管锚索拉拔试验。张拉标定试验表明,内嵌于钢绞线中心丝材料中的准分布式FBG传感器成活率为100％,应变灵敏度集中在0.0012,应变-波长的拟合度皆超过0.999。拉拔试验结果表明,内嵌式FBG传感器可有效监测全长粘结型锚索轴力分布规律;且传感器可实现对锚固段、自由段应力传递规律的定点监测;为锚索浇筑长度的设计、张拉应力的补充提供了计算依据。     

基于RPC梁的准分布式光纤光栅传感器性能分析

目的研究内嵌预压式封装的准分布式光纤光栅(FBG)传感器在活性粉末混凝土(RPC)梁中的监测问题及评估其性能.方法以无粘结预应力RPC试验梁为载体,将5个FBG传感器串联并内嵌封装于梁内部钢绞线和钢筋中,构成准分布式传感网络,实现结构整体多点监测;对封装有准分布式FBG传感器的钢绞线进行重复张拉试验,观察传感器监测情况;对分别施加不同预应力的三根RPC梁进行两点集中加载试验,分析传感器对梁的监测情况.结果准分布式FBG传感器响应灵敏,应变-中心波长变化值拟合线基本重合,应变灵敏度与理论值非常接近,应变监测量程均能达到7 500×10~(-6)以上,可与钢绞线很好的协同变形;同一筋材各测点处FBG传感器的应变发展趋势基本一致,荷载-应变曲线图出现两处明显拐点,对应混凝土梁第一条裂缝出现和钢筋屈服时刻,与理论相符;FBG传感器监测稳定,与同测点位置的电阻应变片数据基本相同,且信号更加稳定.结论多点准分布式FBG传感器对RPC梁监测精准,稳定性好,该监测方法为预应力结构的分布式监测提供了新思路.     

光纤光栅自感知钢绞线在后张有黏结预应力结构中的监测

有效监测后张法有粘结预应力结构在施工过程中产生的短期预应力损失大小是评估整个预应力结构安全性的重要手段。基于对现有预应力损失监测难题及预应力损失计算的理论分析,提出了光纤光栅自感知钢绞线短期预应力损失的监测技术。基于此技术,有效监测了直线及曲线孔道梁的短期预应力损失,并与应变片监测值及理论计算值进行比较。监测结果表明：直线孔道梁短期预应力损失率约10% ,曲线孔道梁短期预应力损失约24% ;对比理论计算值,应变片的误差最大接近10.01%,且同一测点处不同应变片最大差值接近10%,数据离散型较大,而光纤光栅监测到的梁内最终有效应力误差最大仅为4.60%,且在监测过程中始终保持良好的监测性能,可见光纤光栅传感器相比电阻应变片更适合体内预应力监测。     

基于FBG-BOTDA联合感测的岩层运动试验研究

为研究采场上覆岩层运动过程中的应力应变,将准分布式布拉格光纤光栅技术(FBG)和基于脉冲预泵浦布里渊光时域分析的分布式光纤传感技术(PPP-BOTDA)联合应用于相似材料模型试验的测试中。在2 m平面应力模型内埋设2根分布式传感光纤和2个光纤光栅应变传感器,模型尺寸2 000 mm×180 mm×1 700 mm,几何相似比1∶250,测试主关键层由弯曲下沉发育至断裂的变形运动过程。试果表明,2煤开采过程中分布式传感光纤应变曲线体现了岩层的连续变形下沉,曲线中间位置出现应力集中;3煤开采过程中分布式传感光纤应变曲线体现了发生断裂的岩层运动,断裂后的岩层应力得到释放;连续变形下沉的岩层FBG传感器应变曲线呈宽缓峰状,应变值达到4 367.48με;断裂的岩层曲线呈尖峰状,最大应变值达到4 892.82με.实现了模型试验中主关键层由连续体转变为半连续体过程的实时监测。     

基于ANSYS不同螺旋槽规格的钢丝应力分析

目的研究在钢绞线中心丝上设置螺旋式凹槽并植入光纤光栅的智能钢绞线,解决对大应力应变钢绞线损伤破坏全过程的实时监测问题.方法螺旋槽的角度对光纤光栅传感器的应变灵敏度起着关键性作用,同时螺旋槽宽和槽深影响了钢绞线的应力情况,基于ANSYS有限元软件,通过改变不同螺旋槽角度、宽度和深度,对螺旋槽中心丝的最大应力、最大位移和螺旋槽内应力变化率方面进行分析.结果不同螺旋槽规格对智能钢绞线的力学性能及应变监测量程有着重要的影响,当螺旋槽钢丝槽深0.3 mm,槽宽1.2 mm,角度为45°时,该螺旋槽钢丝的最大应力和最大位移适中,螺旋槽内应力变化率为57.1%,应力集中情况较小,对钢绞线承载力影响较小.结论该ANSYS分析为螺旋槽中心丝对智能钢绞线力学性能及大量程应变监测性能提供有效的依据.     

索桁张拉结构形状设计及找力分析

为研究索桁张拉结构的形状判定和自应力求解问题,通过ANSYS有限元软件,提出了基于合理位形改进的力迭代法.首先,基于索桁张拉结构所特有的拓扑关系,从其合理位形出发,推导了形状判定的简洁判断公式.然后,提出了改进的力迭代法,用以求解索桁张拉结构的自应力模态.迭代过程中,更新后的索力逐渐逼近目标值,并在目标预应力作用下得到结构的不平衡位移.算例结果表明,所提方法可一次性确定索桁架的合理形状,且迭代5次左右便可求得结构的自应力模态,所得结果与已有方法的结果相比最大误差为0.48%,满足精度要求.将基于平面索桁架得到的自应力模态代入空间索桁张拉结构中,计算结果接近,内力最大误差为0.030%,且不平衡位移较小,从而证明了由平面索桁架组装成空间索桁张拉结构的可行性.     

张拉方式对预应力锚索支护结构特性影响的室内模拟试验

预应力锚索不同的张拉方式对边坡支护结构的影响不同。采用微机静载锚固试验机进行了预应力锚索加固边坡室内模拟试验,通过沿钢绞线轴线方式张拉和与钢绞线轴线成25°夹角方式张拉结果对比,分析了两种张拉方式对支护结构受力和变形的影响,为边坡的稳定性评价提供技术依据。结果表明:不同的张拉方式对钢绞线抗拉强度的影响不同。沿钢绞线轴线张拉,破坏荷载强度平均值为1 918.60 MPa,钢绞线在组装件中间断裂;与钢绞线轴线成25°夹角方式张拉,破坏荷载强度平均值为1 754.69 MPa,钢绞线在两端锚具附近断裂。     

大桥箱梁预应力施工控制研究

本文以K33＋560大桥预应力箱梁为例,介绍了后张法预应力钢绞线的张拉施工控制技术,阐述了张拉、复核是设计预应力准确施加的方法,提出了计算与施工时的注意事项。在张拉前控制要点为：管道定位必须准确,确保孔道不堵塞;钢绞线下料准确,确保张拉作业工作长度;计算“双控”数据准确,确保张拉误差在容许范围。在张拉中控制要点：理顺张拉顺序,确保应力施加对梁体不造成损害;控制张拉、回油速度,保证应力有效释放;及时检查千斤顶有无滑丝,防止意外事故发生。在张拉后控制要点：控制压浆时间,保证应立即能完全释放,又不致于松弛;严格按规范进行孔道压浆,确保梁板承载能力。     

基于内嵌光纤栅技术的钢筋混凝土梁自振频率监测试验研究

推进单一传感器多功能化发展是结构工程监测技术领域中新的研究热点之一。本文通过对以内嵌光纤光栅(Fiber Bragg Grating,FBG)应变传感器的钢筋为受力筋的钢筋混凝土小梁进行ABAQUS模态分析、人工激励试验和抗弯试验,探究内嵌于钢筋的FBG应变传感器监测钢筋混凝土梁未加载和损伤状态下的自振频率方案的可行性。结果表明：通过人工激励试验获得的未加载试验梁的自振频率约为37.43Hz,与ABAQUS有限元模态分析结果38.366Hz和理论计算得出的试验梁横向振动一阶自振频率理论计算结果36.167Hz基本一致,误差不超过2.5%;在抗弯试验中,试验梁出现破损后FBG应变传感器仍能够稳定监测到结构的自振频率,在试验全过程中,FBG应变传感器能实时监测钢筋的应变变化情况,实现了用内嵌于钢筋的FBG应变传感器同时进行结构自振频率监测和应变监测的目的。     

二次张拉钢绞线箱梁腹板竖向预应力损失研究

为了研究二次张拉钢绞线竖向预应力损失,进行了二次张拉钢绞线的矩形板试验,同时测试了采用二次张拉技术的实桥箱梁腹板竖向预应力的应力损失,并与传统的精轧螺纹钢竖向预应力体系进行比较.测试结果表明,采用二次张拉钢绞线技术后,箱梁腹板的即时竖向预应力损失基本上可以降低至10%以内,远小于精轧螺纹钢体系的竖向预应力损失率,可有效地提高箱梁腹板竖向预应力效率和抗剪可靠性.最后结合试验结果,探讨了管道摩阻、接缝压缩、锚具变形及回缩、弹性压缩、钢绞线松弛和混凝土收缩徐变等二次张拉竖向预应力各项损失的影响因素,并对各项二次张拉竖向预应力损失的设计取值方法提出了建议.     

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.