地基基础设计要考虑地基土体的先期固结压力

首先介绍了土体的先前固结压力及土体对应的分类,并以此分类着重分析了在进行地基基础设计时为何要考虑地基土体的先前固结压力,最后阐述了几种先期固结压力的推求方法及考虑先前固结压力沉降的计算方法。     

南沙软土固结变形特性试验研究

在一系列室内固结试验的基础上 ,探讨了南沙软土的固结变形特性。试验结果表明 ,南沙软土的次固结效应显著 ,主、次固结的划分与固结压力有关。随着固结压力的变化 ,次固结系数表现出与当前应力状态有关的变化规律。当处于正常固结状态时 ,次固结系数近似为一常数。同时 ,固结系数和固结压力、次固结系数和压缩指数之间均有较好的相关性。     

浅析土体的单向固结试验及影响固结试验的因素

本文阐述了单向固结的定义和原理,对单向固结的两种试验方法进行了分析比较,对可能对土体固结产生影响的各种因素进行了分析讨论,以保证土体样品固结试验的顺利实施和结果的科学准确。经研究分析土体的单向固结试验对于地质研究和建筑具体应用都有着十分重要的意义。     

珠海某度假村软土固结特性试验研究

珠海某度假村地处珠江鸡啼门入海口,广泛分布欠固结的淤泥质软土层,通过大量的室内固结试验,对该地区软土的固结特征进行了统计与分析研究,并对典型地层作了沉降计算。     

标准固结试验与快速固结试验方法的对比分析

介绍了标准固结法与快速固结法,并通过工程实际对两种方法分别测得的压缩系数进行了对比,指出压缩系数的大小不仅与试验方法有关,同时与土的性质也有很大的关系。     

三亚海相软土次固结特性研究

港口工程建设中经常遇到海相软土地基,海相软土是一种流变性很强的饱和软粘土,次固结变形在总变形中占有一定的比重,次固结系数是用来计算次固结变形量的一个重要参数。现有计算软土次固结变形的常用方法是不考虑荷载对其影响的,大量的试验表明荷载对次固结有较明显的影响。本文以三亚海相软土为例,根据室内试验成果,对其次固结变形特性与荷载的关系进行了分析研究,得出了一些规律性结论,对海相软土地基的设计与工程实践有指导意义。     

吹填区软土固结及次固结特性试验研究

对某吹填区软土进行了不同固结压力、固结时间、排水距离、初始孔隙比等的对比性固结试验,研究了软土的固结及次固结特性。试验结果表明:次固结系数与压缩指数呈较好的线性关系,压缩性指标与上覆固结压力密切相关;固结变形与先期固结压力有关,在超固结阶段呈线性变形、正常固结阶段呈黏塑性变形的特征;次固结系数随固结压力变化可分3个阶段,阶段Ⅱ(p_c相似文献   

泥炭土的固结特性试验研究

沉降量大且沉降持续时间长是修建在泥炭土地基上的工程所面临的主要问题,而目前国内外学者对泥炭土固结特性的研究结果不尽一致。鉴于此,本文以云南某高速公路泥炭土路段为依托,参照一般土体的室内土工试验方法,对不同有机质含量的泥炭土进行了基本性质试验和一维蠕变试验。结果表明:有机质含量越高,泥炭土的次固结变形量越大。强泥炭质土和泥炭在不同压力下主固结完成时间较短,且基本不受固结压力的影响,这与淤泥质土的相应规律有较大差别。此外,先期固结压力对强泥炭质土和泥炭的次固结沉降速率有很大的影响,而且当荷载大于先期固结压力时,按照一般土体的试验方法进行一维固结试验所得强泥炭质土、泥炭的e-lgt曲线未出现反弯点。弱泥炭质土可参照一般软粘土的方法用e-lgt曲线确定次固结系数,其次固结系数随压力的变化规律与一般软土的变化规律一致,即次固结系数随固结压力先增大后减小。     

饱和粘性土地基固结的概率分析

对竖向固结系数的空间概率特征进行了统计研究 ,并进行了固结系数分布类型对固结度的敏感性分析。分析结果显示竖向固结系数的分布类型对固结度的概率计算有较大的影响。为便于工程设计应用 ,文后还提供了设计系数图表。     

错误的“两相非连续介质固结理论”——与徐日庆先生等商榷《两相非连续介质固结理论》一文

该文认为徐日庆等人《两相非连续介质固结理论》一文得出的固结模型不正确,并作了阐述分析。     

十漫高速公路沥青面层质量控制与施工工艺分析

以十漫(十堰-漫川关)高速公路建设项目为依托,针对面层施工参数的变异性,主要包括级配、油石比、孔隙率和压实度等参数,在分析变异性产生原因的同时,还着重分析了各参数变异之间的相关性,另外还考虑到某些参数对工程质量影响的敏感性。同时,在提出了相应的预防措施。     

Adhesion of in situ precipitated calcium carbonate in the presence and absence of magnetic field in quiescent conditions on different solid surfaces

Deposition of in situ precipitated calcium carbonate from Na(2)CO(3) and CaCl2 solutions on different substrates, i.e. stainless steel, copper, aluminium, and glass, was investigated at different temperatures, 20 degrees C, 40 degrees C, 60 degrees C and 80 degrees C, both in the absence and presence of S-S 0.1T magnetic field (MF). It was found that in quiescent conditions during 2h the amounts deposited firmly on the surfaces decreased with increasing temperature. If MF was present the deposition was reduced at all temperatures, and depended on the nature of the substrate. The largest MF effect was found on glass at 60 degrees C, which amounted 50% reduction of the deposit. However, at 80 degrees C no deposition was found in the presence of MF on aluminium surface. At this temperature the reproducibility of the experiments was poor, and an additional effect due to the metal surface corrosion (especially that of aluminium and copper) may be thought in alkaline environment of the experiments (pH ca. 10). Based on optical microscope photographs, it was concluded that the amounts of crystallographic forms of CaCO3 depended on the nature of substrate on which the precipitation and then the adhesion took place. To some extent the ratios of CaCO3 forms precipitated were different in the bulk phase than on the substrate surfaces at the same temperature, and this conclusion was based on the X-ray diffractograms. Some possible mechanisms causing MF effects are discussed.     

基于模糊层次分析法的混凝土生命过程与环境共融性评价

作者在“混凝土生命过程与环境共融性”^[1]一文的基础上，首次提出以层次分析法和模糊数学为基础的混凝土生命过程与环境共融性评价模型。主要介绍了层次分析法与Fuzzy函数在混凝土生命过程环境共融性评价中的应用。通过此模型。为研究者或决策者评价混凝土与环境的关系提供了有利的支持。     

基于HTCPN的虚拟建设工作流管理系统框架设计

构建了支持虚拟组织业务协同工作的信息集成平台。基于HTCPN定义工程项目建设工作流模型,完整描述工程项目建设过程中的静态结构和动态行为,在此基础上,采用工作流技术,参照WfMC提出的工作流管理系统参考模型,提出支持面向分布应用的虚拟建设工作流管理系统框架结构,并对系统模块和接口进行了详细论述。     

不均匀地基埋地箱涵伸缩缝的地震位移响应研究

对位于不均匀地基的某核电厂地下排水箱涵的地震反应进行了数值研究,着重探讨了箱涵伸缩缝的位移反应特性。采用场地相关地震动时程,考虑土体为理想弹塑性材料,基于FLAC~（3D）软件进行了非线性动力分析。结果表明,在地震作用过程中,埋地箱涵的位移取决于周围岩土体的运动;各管段的整体位移虽较大但各伸缩缝的相对位移数值较小;相邻箱涵段轴向不会发生碰撞;选择及设置伸缩缝止水带时应注意其横向最大变形应大于最大横向地震位移,以免发生剪切破坏。     

Force transfer mechanism on fastener section of mechanically anchored waterproofing membrane roofs under wind pressure during typhoons

The wind pressure, billow of a PVC sheet, and fastener load of a mechanically anchored waterproofing membrane system on a building rooftop were measured during a typhoon. The results showed that the waterproof sheet billowed upward, and the height of the billow was greater on the windward side that was under higher negative pressure. The axial and lateral forces acting on the fastener of the waterproof sheet were measured by a six-component force transducer, and it was found that the lateral force acting on the windward side of the fastener was larger. The tensile force acting on the fastener section was calculated using an equation for rooftop wind pressure. Finally, the method used to determine the fastener's position and the types of materials best-suited to cope with wind pressure on the roof were proposed, and the safety of this waterproof system was evaluated.     

园林害虫发生动态监测和治理咨询系统

采用Visual Basic 6．0为程序设计语言，使用面向对象程序设计思想和可视化编程技术，开发园林害虫发生动态监测和治理咨询系统。提出在数据库和VB配合下建立害虫地理信息系统（GIS）的模式，采用图表控件对数据库中的数据进行直观的动态分析，在提供入侵害虫信息资料基础上，进行风险分析。     

Influence of plastic electrical outlet boxes on sound insulation of gypsum board walls

In this paper, the influence on sound insulation of plastic electrical outlet boxes installed on double leaf steel stud gypsum board walls containing cavity absorption was examined experimentally. It was shown that the effect on sound insulation was negligible. It was also shown that the size of the elctrical boxes had not effect on sound insulation.     

Effect of pH on MnOx/GAC catalyzed ozonation for degradation of nitrobenzene

The effect of pH on MnO(x)/GAC heterogeneous catalytic ozonation was investigated. Nitrobenzene was used as a model refractory organic pollutant. It was found that in MnO(x)/GAC catalytic ozonation, the degradation efficiency of nitrobenzene was higher under low pH conditions (pH 2.74-3.52) than that under high pH conditions (pH 6.72-9.61). This result was different from the case of ozonation alone, in which higher pH had positive effect on the degradation of nitrobenzene due to the formation of hydroxyl radical. In the presence of MnO(x)/GAC catalyst, ozone decomposition was accelerated, and higher pH condition favored ozone decomposition. It was assumed that hydroxyl radicals might not be the dominating active species in the catalytic oxidation, for the presence of t-butanol did not have any influence on MnO(x)/GAC heterogeneous catalytic ozonation. Adsorption of organic micropollutants on MnO(x)/GAC catalyst was an important step and would have direct influence on the effectiveness of catalytic oxidation. It was assumed that the organic pollutants might be further decomposed on the surface of catalyst.     

核电站穹顶内热环境影响因素研究

以CPR1000核电站R55区穹顶为研究对象,基于计算流体力学(CFD)技术,应用P-1辐射模型对穹顶内部温度场进行了3D稳态数值模拟。分析了太阳辐射、进口风速及环境气温对核电站穹顶内热环境的影响。结果表明:以环境气温对穹顶内热环境的影响最为明显,太阳辐射次之,进口风速的影响最小。所得结果为穹顶内热环境的改善研究提供了依据。