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以大连地铁旁穿高架桥桩基础为背景,利用有限元软件MIDAS/GTS建立了三维数值模型,研究了隧道施工过程桩的内力和位移的变化规律。分析结果表明:桩顶竖向沉降值最大;桩的水平位移先增大,后减小,由正值逐渐变为负值;隧道周围土体的损失使桩周土层发生沉降,产生负摩阻力,使桩的轴力在1015 m处变化很大;沉降槽内,地表隧道中线处沉降值最大,离中心越远其值越小。 相似文献
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对某一卷出现断口分层现象的高强捆带进行了全面的理化性能分析,指出了导致产生该缺陷的可能原因,提出了一些相应的改进措施。 相似文献
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The indirect boundary element method (IBEM) is used to study the surface motion of an alluvial valley in layered half-space for incident plane P-waves based on Wolf’s theory. Firstly, the free field response can be solved by the direct stiffness method, and the scattering wave response is calculated by Green’s functions of distributed loads acting on inclined lines in a layered half-space. The method is verified by comparing its results with literature and numerical analyses are performed by taking the amplification of incident plane P-waves by an alluvial valley in one soil layer resting on bedrock as an example. The results show that there exist distinct differences between the wave amplification by an alluvial valley embedded in layered half-space and that in homogeneous half-space and there is interaction between the valley and the soil layer. The amplitudes are relatively large when incident frequencies are close to the soil layer’s resonant frequencies. 相似文献
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学生实习分层教学浅见 总被引：1，自引：0，他引：1
张锦润 《广东技术师范学院学报》2008,(6)
分层教学是根据个人在发展过程中客观存在的差异,应用因材施教的原则,从而符合学生的学习心理,能更有效的调动学生的学习积极性。分层教学要对目标、授课、课堂、学生、考评、训练内容等进行分层,用不同的标准来区别评价,分层教学有利于促进学生能力的提高。 相似文献
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根据工程实例,利用基于有限差分理论的计算程序建立数值分析模型,对深基坑开挖与支护过程中临近基坑的建筑物地基沉降进行数值分析计算,得到了临近建筑物地基沉降的变化规律及沉降量具体数值,将数值分析结果与实测值进行对比,结果基本一致.研究表明,数值分析可以用于基坑开挖和支护过程中相邻建筑物地基变形的预测分析,为实际工程的设计和施工提供依据. 相似文献
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Cover-bearing-type bucket foundation for offshore wind turbines has been paid more and more attention due to its low cost and great bearing capacity. In order to ensure the cover-bearing mode, the muddy soil inside the bucket foundation should be reinforced by some soil consolidation methods, such as negative pressure and electro-osmosis. Firstly, tests were conducted to obtain the reasonable current density. Meanwhile, to improve the electro-osmotic speed and effectiveness, other factors such as intermittent power and layout of electrode, were also studied in the tests. Then, the soil reinforcing tests by negative pressure combined with electro-osmosis were performed for the muddy soil consolidation inside the bucket foundation. The results showed that soil reinforcement by negative pressure was quicker and more obvious during the early phase, and electro-osmotic method can affect more range of soil by rational arrangement of electrodes. Compared with negative pressure, the electro-osmotic method was a continuous and relatively slow process of reinforcement, which was complementary to the negative pressure method. The voltage value of electro-osmosis had little effect on the muddy soil reinforcement inside the bucket foundation, and 1.5 A was chosen as the most reasonable current value for scale model testing in the electro-osmotic method. 相似文献
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社会分层理论是划分社会成员等级结构的重要方法之一。传统分层理论与民国时期民间分层意识存在着分离的事实值得深入研究。 相似文献
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随着我国新课改的逐步深入,学校普遍开始运用新的教学方式及教学理念。学生如果没有独立的思考能力以及足够的知识积累,逻辑思维能力就不会提高。“分层导学案”的运用有效提升了学生的逻辑思维能力。文章通过对北师大版九年级数学教材的分析,探究“分层导学案”模式在教学中的实践。分层导学案的教学模式不但可以提高学生学习数学的主动性,还可以有效提升教师的课堂教学效率。 相似文献
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张华林 《福建工程学院学报》2002,(3)
通过方案比较 ,与分析历时一年加筋土挡墙的地基沉降、侧移、孔隙水压力及墙背、墙底土压力的实测资料 ,证明加筋土挡墙 ,较经济技术上具有明显优势 ,且指出该类挡墙稳定安全系数施工期最小 相似文献
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张锦润 《广东职业技术师范学院学报》2008,(6):131-133
分层教学是根据个人在发展过程中客观存在的差异,应用因材施教的原则,从而符合学生的学习心理,能更有效的调动学生的学习积极性。分层教学要对目标、授课、课堂、学生、考评、训练内容等进行分层,用不同的标准来区别评价,分层教学有利于促进学生能力的提高。 相似文献
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许元 《深圳职业技术学院学报》2008,7(2):24-28
在高层建筑深基坑支护各种方案中,通常土钉支护费用最低,当深基坑土质条件较差,如沿海地区淤泥质土层,含水量较大,基坑垂直支护面难以成型,难以采用土钉支护方案,引用钢板桩支护原理,本文采用25号槽钢与土钉组合深基坑支护方案,解决土钉在软土中应用不足和发挥槽钢封面的特点,成功解决软土地区土钉支护问题,由于槽钢可以全部回收重复使用,该支护方案造价较低,经济效益较好。 相似文献
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This paper presents a semi-analytical method to solve one dimensional consolidation problem by taking consideration of varied compressibility of soil under cyclic loading. In the method, soil stratum is divided equally into n layers while load and consolidation time are also divided into small parts and time intervals accordingly. The problem of one-dimensional consolidation of soil stratum under cyclic loading can then be dealt with at each time interval as one-dimensional linear consolidation of multi-layered soils under constant loading. The compression or rebounding of each soil layer can be judged by the effective stress of the layer. When the effective stress is larger than that in the last time interval, the soil layer is compressed, and when it is smaller, the soil layer rebounds. Thus, appropriate compressibility can be chosen and the consolidation of the layered system can be analyzed by the available analytical linear consolidation theory. Based on the semi-analytical method, a computer progra 相似文献
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为了表明扩孔锚杆在软土基坑工程中的应用价值,文章对福建沿海地区的一个软土基坑工程实例进行了分析。结果表明,扩孔锚杆不仅显著提高了其抗拉承载力,而且施工速度快,有利于基坑土方的开挖。因此,扩孔锚杆在施工工期短或不适合布置内支撑的基坑支护工程中具有十分广阔的应用前景。 相似文献
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INTRODUCTION It is recognized that the transfer of soil moistureand heat occur simultaneously and are interrelated.Since the 1950s, many models have been developed,based on two nonisothermal water-heat coupledmodels by Philip and de Vries (1957) and Taylor andLary (1964), respectively. In China, some researcheson modeling coupled transfer of soil moisture andheat have also been conducted on the arid soils innorthern China (Kang et al., 1993; Guo and Li, 1997;Hu et al., 1992; … 相似文献
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Simulation models of heat and water transport have not been rigorously tested for the red soils of southern China.Based on the theory of nonisothermal water-heat coupled transfer, a simulation model, programmed in Visual Basic 6.0, was developed to predict the coupled transfer of water and heat in hilly red soil. A series of soil column experiments for soil water and heat transfer, including soil columns with closed and evaporating top ends, were used to test the simulation model. Results showed that in the closed columns, the temporal and spatial distribution of moisture and heat could be very well predicted by the model,while in the evaporating columns, the simulated soil water contents were somewhat different from the observed ones. In the heat flow equation by Taylor and Lary (1964), the effect of soil water evaporation on the heat flow is not involved, which may be the main reason for the differences between simulated and observed results. The predicted temperatures were not in agreement with the observed one with thermal conductivities calculated by de Vries and Wierenga equations, so that it is suggested that Kh, soil heat conductivity, be multiplied by 8.0 for the first 6.5 h and by 1.2 later on. Sensitivity analysis of soil water and heat coefficients showed that the saturated hydraulic conductivity, Ks, and the water diffusivity, D(θ), had great effects on soil water transport; the variation of soil porosity led to the difference of soil thermal properties, and accordingly changed temperature redistribution,which would affect water redistribution. 相似文献
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组播作为一种节约网络带宽、降低网络负载的有效手段,在视频传输中具有广阔的应用前景。本文针对组播中的会话内公平性问题,深入研究了多速率组播分层解决方案的实现机制,并基于目前的研究现状和进展指出了分层组播现存的有关问题。同时为分析分层解决方案在解决组播会话内公平性问题中的有效性,文中通过网络仿真器NS进行了实验评价。 相似文献
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任瑞平 《杨凌职业技术学院学报》2014,(1):36-38
通过杨凌示范区田园居内高层建筑地基处理方案的设计实例分析,对所选定的灰土垫层地基的计算方法作了简明的阐述。通过沉降观测,验证建筑物地基方案设计的正确性,为灰土垫层的进一步推广提供了一定的依据,为同条件工程确定一个比较具体的标准及作为条件相似工地的施工经验参考,具有一定的工程应用价值。 相似文献
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林智勇 《福建工程学院学报》2016,(4):318-323
利用数值分析方法建立了软土地基模型,采用比奥固结理论,计算分析了真空预压下的软土地基流固耦合作用;并进一步分析了真空度损耗率、密封墙、塑料排水板打设深度等因素对软基加固效果的影响。分析结果表明:在抽真空早期,地表沉降增长很快,达到一定天数后,沉降值逐渐趋于稳定;真空负压沿深度、水平方向上损耗,在加固软土外围形成一个零孔隙水压力面;真空度损耗率、塑料排水板打设深度对真空预压加固软土的效果影响很大;侧向密封墙对加固区内土体影响不大,但其限制了真空负压的侧向传递,使影响区的地基沉降大幅减小。 相似文献
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邹晓川 《重庆第二师范学院学报》2012,(3):8-11
采用氢氟酸络合法合成了高结晶度的层状苯乙胺-N,N-双甲基膦酸盐（IV）,并对其结构和形貌进行了表征。结果表明这类化合物具有典型的层状结构,层间距分别为1．70nm,1．69nm,比相应的a-ZrP（0．76nm）、a-TiP（0．754nm）增加了多达0．940nm、0．936nm;同时,直到400℃层状结构才开始受到破坏,表明其热稳定性良好。 相似文献