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采用主成分分析方法, 就粘性土多指标反映其性质的规律进行了研究. 研究表明, 采用液性指数作为单一指标的传统粘性土物理状态划分方法, 在反映亚粘土和亚砂土性质时不尽合理. 而采用液性指数IL结合孔隙比e反映粉质粘土的特性更加合理. 同样,孔隙比e比液性指数IL能更好地描述亚粘土的天然特性. 采用人工神经网络结合主成分分析, 得出应用孔隙比e和液性指数IL两个指标来预测桩侧摩阻力更为精确. 同时发现在一定临界影响深度范围内(20～30 m), 桩侧摩阻力随深度的增加而增加, 且粘性土的稠度愈硬, 临界深度愈浅. 相似文献
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谈传华 《石家庄铁路工程职业技术学院学报》2011,(1):41-44
以灌注桩桩土相互作用的原位试验为基础,结合苏嘉杭高速公路具体土层结构、性质特点,采用有限单元法对软土地区的砼灌注桩桩土相互作用进行仿真模拟,研究桩土相互作用、荷载的传递规律、桩土相对位移与桩侧摩阻力的关系,通过桩载试验资料对比,得出三维有限元法的模拟结果与实测值相近。在此基础上,根据侧摩阻力最大值发挥不同步这一特点和桩土相互作用的实质及荷载传递规律,提出一种新的单桩极限承载力计算公式。 相似文献
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桩土相互作用及单桩承载力确定模拟研究 总被引：4，自引：0，他引：4
谈传华 《石家庄铁路职业技术学院学报》2011,10(1)
以灌注桩桩土相互作用的原位试验为基础,结合苏嘉杭高速公路具体土层结构、性质特点,采用有限单元法对软土地区的砼灌注桩桩土相互作用进行仿真模拟,研究桩土相互作用、荷载的传递规律、桩土相对位移与桩侧摩阻力的关系,通过桩载试验资料对比,得出三维有限元法的模拟结果与实测值相近.在此基础上,根据侧摩阻力最大值发挥不同步这一特点和桩土相互作用的实质及荷载传递规律,提出一种新的单桩极限承载力计算公式. 相似文献
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李为国 《福建工程学院学报》2011,9(6)
根据某工程2根人工挖孔桩静载试验的结果,预测了桩的极限承载力,并根据侧阻力随荷载和位移增加的变化情况,证明了护壁的存在对侧阻力后期的发挥会产生不利影响,同时也说明目前设计时不计桩侧摩阻力有一定的合理性.对桩端及桩侧承载力所占的比例进行了分析,分析结果表明,如果孔桩进入强度较好的风化岩以上岩土层时,不设护壁时的桩侧阻力相当可观,设计时应当考虑其桩侧阻力的贡献;如果设计扩大头将破坏其侧阻力的发挥,甚至会因桩端土层的软化而导致工程事故发生,造成工期延误和不必要的经济损失.基此,文章最后提出了挖孔桩优化设计和施工工艺创新的思路. 相似文献
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《浙江大学学报(A卷英文版)》2020,(6)
目的:基于极限平衡理论和诸多简化原则的经验公式方法难以适用于复杂的复垦地层中灌注桩的侧摩阻力计算。本文旨在探讨复垦地层中灌注桩在静力加载条件下的侧摩阻力发展规律和特性,并应用深度学习方法,以提高灌注桩侧摩阻力的预测精度。创新点:1.设计现场试验,研究近海复垦地层中灌注桩的承载能力特性;2.建立深度学习预测模型,高精度预测工作荷载下灌注桩的轴力和侧摩阻力。方法:1.通过实验分析,探明复垦地层中不同土层与桩体的相互作用和桩体侧摩阻力的发展规律;2.通过理论计算,指出经验方法在复垦地层灌注桩承载力计算中的缺陷和不足;3.通过序列化的人工智能方法建模,利用土体物理力学参数和桩身试验实测数据,对比验证深度学习方法的精度和计算效率。结论:1.灌注桩适用于复垦地层,能够为基础设施提供足够的承载力;2.经验方法对灌注桩中部桩体的极限侧摩阻力估计良好,而对地层条件较差的桩身两端的估计则存在较大偏差;3.深度学习方法能够综合考虑地层和桩体的相互作用,并且能精确预测在不同工作荷载和极限荷载下的侧摩阻力和桩身轴力,因而适用性更广。 相似文献
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用有限棱柱单元法对采用长桩的单桩与土相互作用系统进行了三维弹塑性分析，并开发出一种可模拟半无限空间地基土边界条件的无限棱柱元．计算中考虑了承台对地基土的约束作用及桩土之间的竖向相对位移，地基土的本构模型采用修正剑桥模型．分析了集中荷载作用下摩擦长桩与土相互作用系统，得到了合理的荷载－沉降曲线及桩侧摩阻力的分布曲线，为长桩的研究与设计提供了一种有效的计算方法 相似文献
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张俊斌 《福建工程学院学报》2003,1(3):49-51
通过某小区三幢住宅楼9根小截面静压预制桩静载试验成果分析，表明以侧阻力为主的摩擦型预制桩Q—s曲线呈双曲线的特征。采用斜率-倒数法对该小区静压预制桩单桩极限承载力进行预测，并将预测结果与理论计算结果进行对比，分析结果表明《建筑桩基技术规范》JGJ94—94中有关预制桩承载力指标的取值偏低，其指标不适合小截面静压预制桩。结合桩基施工终压力和每延米压桩耗能的对比分析，表明桩的竖向极限承载力与终压力存在一定的比例关系，但与压桩耗能不存在比例关系。 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献