基于扰动状态概念的桩-土接触面荷载传递模型

基于扰动状态概念(DSC),假定桩-土接触面单元中相对完整(RI)状态部分的抗剪强度服从线弹性理论,完全调整(FA)状态部分的抗剪强度服从理想塑性理论,进而建立桩-土接触面荷载传递模型.针对桩-土接触面进行了大型直剪试验,试验结果表明:桩-红黏土接触面剪切过程中,接触面表现出应变软化特性,且随着法向应力的增加,软化现象越明显;桩-粉质黏土接触面剪切过程中,接触面表现出轻微应变硬化特性.利用桩-土接触面荷载传递模型计算得到的剪切应力-剪切位移曲线(τ-s曲线)与直剪试验得到的τ-s曲线吻合较好,验证了基于DSC的桩-土接触面荷载传递模型具有较好的准确性与适用性.     

抗滑桩不同布桩方式加固效果对比模型试验研究

为研究不同布桩方式抗滑桩加固效果,设计了一套基于三维激光扫描等多种非接触测量方法的滑坡模型试验系统.试验系统通过减速电机的慢速牵拉诱发滑坡,解决了传统模型试验技术诱发滑坡时难以捕捉滑坡启动点的难题,并利用三维激光扫描、DIC测量等多种非接触测试手段获取了滑坡演化过程中位移、应力、破裂扩展等多物理场数据,实现了对滑坡演化全过程的模拟.对滑坡未加固状态、抗滑桩直线布桩和拱型布桩3种状态下加固效果进行了一系列模型试验研究.试验结果表明,在未加固状态下,坡体最大抗滑力为95N,抗滑桩直线布桩和拱型布桩状态下,坡体最大抗滑力分别为140N和180N.直线布桩和拱型布桩的最大抗滑力分别提高了47%和89%.拱型布桩滑坡体后缘拉裂缝规模更小,坡体下滑距离更短,土拱影响区域更大,能更好地发挥桩侧摩阻力,提高坡体抗滑能力.结合试验数据,提出了抗滑桩拱型布桩条件下的最大桩间距计算公式.     

预应力高强混凝土管桩桩身抗剪承载力试验

在无轴压和轴压1 300 kN作用下对PHC-AB400(80)型管桩进行桩身抗剪承载力足尺构件试验.详细介绍加载装置和试验方法,得到该桩型在无轴压受剪和轴压受剪状态下的开裂荷载和极限荷载.基于管桩在无轴压受剪和轴压受剪状态下裂缝发展的观察以及对支座与加载点间剪跨段混凝土主拉应力与主拉应力角的分析,研究该桩型的破坏过程.比较由《预应力混凝土管桩图集》中的公式计算得到的数值和试验值可知,公式值约为试验值的58%.因此,建议管桩抗剪承载力的计算公式中考虑箍筋的抗剪作用.     

钻孔灌注桩抗拔荷载的传递机理研究

通过对钻孔灌注桩的现场原型抗拔试验,研究了钻孔灌注桩抗拔时荷载的传递机理,由实测桩身内力确定了荷载沿桩深度的变化、桩侧摩阻力沿桩深度的分布规律及桩的荷载传递函数,并提出了合理设计抗拔桩的思路。     

U型槽结构抗浮桩设计计算方法探讨

U型槽结构在承受自重、汽车荷载、土压力、水浮力等荷载作用时,位于结构底板下不同平面位置的抗拔桩受力大小差别较大,按照以往各桩均匀受力的计算假定进行设计会造成很大的误差,导致结构不安全。本文采用空间有限元分析的方法,建立空间板单元模型模拟U型槽结构抗浮桩的实际受力状态,总结出抗浮桩受力的分布规律,以供U型槽结构抗浮桩设计中参考。     

桩周上覆荷载作用下抗拔桩弹性变形解析解

抗拔桩在实际工作过程中,桩周土体表面存在荷载作用,会对抗拔桩的桩土相互作用特性产生影响。采用桩侧剪切位移传递法与弹性理论相结合,考虑桩周土体表面上覆荷载作用,推导出抗拔桩的桩顶位移、桩身轴力以及桩侧摩阻力随桩身分布的弹性解析解。在此基础上,通过一个实例利用解析解分析上覆荷载作用对抗拔桩位移、轴力以及摩阻力分布的影响。结果表明:桩周土体表面上覆荷载增大了桩上部的侧摩阻力,可有效增大抗拔承载力。与模型试验结果进行对比,发现给出的解析解可较好反映抗拔桩在实际工作状态下的荷载-位移关系(小于极限荷载的40%),可为后续研究提供参考。     

红层锚杆抗拔力学性质模型试验研究

为了解红层软岩的崩解特性对锚杆力学性质影响的规律，设计了红层软岩中锚杆抗拔试验和红层软岩的耐崩解试验.首先通过红层锚杆抗拔试验，得到了红层锚杆在循环荷载下的荷载-位移曲线(P-S)和荷载-弹／塑性位移曲线(P-Se，P-Sp)的演化规律，然后通过耐崩解试验得到红层软岩的耐崩解指数Id2，最后将锚杆的力学性质与红层软岩的耐崩解指数Id2联合起来进行分析.分析表明，随着耐崩解指数的降低，红层锚杆抗拔力学性质变差.     

承压螺旋桩斜向荷载试验与极限荷载判定分析

桩基础所受外载荷并不是单一方向的载荷,如输电塔结构,在承受竖向压力的同时承受着水平载荷作用,导致基桩受到斜向压荷载作用,该种条件的桩基础极限载荷的确定对结构设计的安全性极为重要.为此,开展承压螺旋桩基础斜向荷载的试验研究工作.模型试验采用1#(叶片距宽比为3.14)和2#(叶片距宽比为5)2种桩型,1#桩型试验5次,2#桩型试验4次,2组共计9次试验.承压螺旋桩斜向荷载试验表明:①本次试验桩顶水平位移较竖向位移大了1个数量级,螺旋桩基础的竖向承载能力并未得到充分发挥,竖向分量限制了背载侧叶片对地基向上的压缩作用,从而提高了基础抗水平载荷的能力.②叶片间距增大时(1#<2#),荷载-位移曲线表现出更为明显的非线性特征,1#和2#桩受载侧地基表面均出现放射性裂纹;1#桩背载侧地基表面沿桩体外径开裂,2#桩的背载侧出现似"拔出体".③可采用F-ΔX0/ΔF方法、S-LogP方法,并根据荷载量变化、桩土相互作用和桩周材料的变形阶段确定螺旋桩基础的斜向极限载荷;本次试验1#桩的判定极限荷载为327.93 N,2#桩为348.06 N.     

桩基挡墙支挡结构极限状态及稳定性分析

以某高速公路高填方路堤中桩基挡墙支挡结构为对象,研究其极限状态及稳定性.基于现场试验监测结果,建立了三维有限差分数值模型.通过对比抗滑桩极限承载力、挡土墙极限位移和基座混凝土极限压应力所对应的路面荷载,提出了桩基挡墙极限状态的确定方法.分析了设计行车荷载下桩基挡墙的稳定性,探讨了填土重度、填土内摩擦角和抗滑桩桩间距等参数对桩基挡墙结构稳定性的影响.研究结果表明:随路面荷载不断增大,桩基挡墙结构首先出现抗滑桩剪切破坏,结构承载力极限状态由抗滑桩抗剪承载力确定;填土重度和内摩擦角对桩基挡墙结构稳定性影响较大,减小桩间距能一定程度上提高支挡结构稳定性.     

静钻根植桩抗压抗拔承载性能试验研究

通过一组静钻根植桩的现场抗压抗拔静载试验,研究了抗压和抗拔状态下静钻根植桩的承载性能.对两根试桩的荷载位移曲线进行了比较分析,并采用有效应力法对试桩的极限侧摩阻力进行计算.试验结果表明:受桩周土体应力状态和桩身泊松效应影响,静钻根植抗拔桩的极限侧摩阻力小于抗压桩的极限侧摩阻力;抗拔桩侧摩阻力完全发挥时的桩顶位置值大于抗压桩侧摩阻力完全发挥时的桩顶位置值;采用有效应力法计算土层的极限侧摩阻力时,需要考虑土层的极限深度(或极限竖向有效应力),当土层深度超过极限值时,采用有效应力法计算土层的极限侧摩阻力需采用极限深度时对应的竖向有效应力值.     

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.     

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.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.