某集装箱码头桩基承载力理论计算与静载试验对比分析

依托某集装箱码头工程的后轨道梁桩基,针对开口钢管桩和半闭口钢管桩两种形式,详细对比国内外常用桩基承载力经验公式计算结果的差异,并与现场静载试验结果进行对比。结果显示：对于砂性土与黏性土成层交替分布的地基,国内外桩基承载力经验公式在侧摩阻力、端阻力、桩端闭塞效应、总承载力计算结果上均存在一定的差异,与静载试验结果相比也有所偏差。按国内规范计算的总承载力与静载试桩结果基本接近,国外经验公式的偏差较大。半闭口桩尖可显著提高砂质地基的桩端承载力,桩端闭塞系数可达0.8以上。相关结论可供类似工程借鉴。     

西班牙Rom规范与中国JTS规范桩基承载力设计方法对比

针对西班牙Rom规范与中国JTS规范中桩基承载力设计方法的异同,对西班牙Rom规范中单桩承载力设计方法以及各自的适用范围进行总结,从两本规范的单桩轴向抗压承载力、单桩轴向抗拔承载力等方面进行对比分析。结合工程实例,分别依据西班牙Rom规范和中国JTS规范对单桩轴向抗压承载力、单桩轴向抗拔承载力进行计算和对比。结果表明,中国JTS规范计算的允许抗压承载力设计值比西班牙Rom规范偏小,而允许抗拔承载力设计值比西班牙Rom规范偏大。     

海上风电大直径超长桩侧阻力抗拔折减系数试验研究

海上风电群桩基础中的单桩需能承受较大的上拔荷载。抗拔承载力往往是决定桩长的控制因素。针对海上风电大直径超长桩的侧阻力抗拔折减系数(抗拔侧阻力/抗压侧阻力)开展研究,通过静载荷试验的方法获得试验桩各土层的抗压侧阻力和抗拔侧阻力实测值,进而得到侧阻力抗拔折减系数,并将其与现行规范推荐值进行对比,验证规范的合理性。研究结果显示,各土层的侧阻力抗拔折减系数几乎都小于规范推荐值。因此,采用规范推荐的侧阻力抗拔折减系数计算大直径超长桩抗拔承载力可能会得到偏危险的结果。     

开口钢管桩桩基承载力桩端部分计算方法探讨

港口工程类设计规范中未明确给出开口钢管桩的桩基承载力计算方法,设计中常参考JGJ 94—2008。建立桩周全部土体与钢管桩蔽塞效应间的关系,并通过实际工程试验加以验证,为开口钢管桩桩基承载力桩端部分计算方法提供新的思路。解决了“JGJ 94—2008《建筑桩基技术规范》中给出的,桩基承载力计算方法中对桩端蔽塞效应系数的计算仅考虑桩端进入持力层的深度,而忽略了持力层以上土体对桩端蔽塞的影响”的问题。     

中美欧日桩基承载力设计规范比较

针对中美欧日各国关于桩基设计方法的异同,在设计理论基础、单桩轴向抗压承载力、单桩抗拔承载力和水平承载力等方面进行了综合对比分析。并以工程实例为基础,计算了桩的抗压、抗拔极限承载力和折算允许值,得出中国规范安全裕度适中、水平承载力计算方法涵盖面广、可向海外推广的结论,并提出了工程设计中的关注点。     

极密实粉细砂层大直径钢管桩桩基参数分析

现行桩基规范缺少极密实粉细砂层桩端阻力和桩侧阻力的规定。结合某海港工程钢管桩基静载及高应变检测,探讨大直径钢管桩在极密实粉细砂层中的桩侧阻力和桩端阻力。高应变检测结果显示,极密实粉细砂层单位面积桩侧阻力范围为93～120. 01 k Pa,平均值为106. 6 kPa,1 500 mm钢管桩桩端阻力范围6. 742～6. 845 MN,平均值6. 780 MN。针对国内外规范对桩基承载力的估算计算结果进行分析,建议极密实粉细砂层桩侧阻力值取90～120 kPa,桩端阻力值取8～12 MPa。     

港口工程单桩垂直承载力经验参数法初探

JTJ 254—1998《港口工程桩基规范》与JGJ 94—2008《建筑桩基技术规范》对单桩承载力计算的参数选取存在不同。从分析两个规范的桩基设计安全度出发,对比了黏土层采用该方法的参数差异和单桩垂直承载力的差异,介绍在工程实践中,解决该差异所采取的勘察工作方法和几种参数取值处理办法,最后对规范修订工作提出了几点建议。     

开口钢管桩桩端土闭塞效应的初步探讨

港口工程中经常使用大直径钢管桩基础,如何考虑开口钢管桩桩端土的闭塞效应是港口桩基设计中经常遇到的技术问题.结合北方某港改造工程中开口钢管桩的施工实践,将高应变动测试桩的统计资料所反映的开口钢管桩承载力桩端闭塞效应和相关规范的推荐方法进行对比分析,可为类似的工程的桩基设计提供借鉴.     

乐清湾大桥超长大直径后压浆灌注桩的自平衡试验研究

基于乐清湾大桥及接线工程的1根超长大直径钻孔灌注桩,通过对桩端后压浆钻孔灌注桩进行自平衡试验,研究桩端后压浆对含黏性土角砾层超长大直径钻孔灌注桩的承载变形特性。结果表明,桩端压力浆液上返能有效地改善了下段桩的桩土边界条件,并增大了桩侧剪切界面阻力和粗糙度,使得下段桩桩侧摩阻力提高了66.67%,且对桩的荷载传递特性产生明显影响;在含黏性土角砾层中桩端后压浆钻孔灌注桩承载力随着桩顶沉降的增加而增加,且在达到极限状态时,极限承载力的可提高幅度58.14%,端阻力可提高幅度60.64%。此外,在含黏性土角砾层中采用桩端后压浆技术不仅可以通过增强端阻力来提升桩基极限承载力,还能提高桩侧摩阻力,且桩侧摩阻力的提高也成为提升桩基承载力的主要原因。     

湛江霞山港区深厚老沉积土地基钢管桩承载力试验分析

通过深厚老沉积土地区钢管桩的压桩试验、拔桩试验和桩身轴力试验,探讨了深厚老沉积土地区钢管桩压桩和拔桩的土阻力分布规律,得出如下结论:深厚老沉积土地区钢管桩压桩状态下侧阻力均值为76.79 MPa,比一般黏性土高27.5%~30.6%;老沉积土拔桩状态下的侧阻力值达到42.4~52.8 MPa;老沉积土拔桩侧阻力和压桩侧阻力的比值均值为0.84,比一般黏性土值要高5%;老沉积土压桩和拔桩侧阻力较为恒定,随着土层埋深和土层厚度的变化较小。这对深厚老沉积土地基中钢管桩的理论研究和工程应用具有指导作用。     

Synoptic transects on the distribution of trace elements (Hg,Pb, Cd,Cu, Ni,Zn, Co,Mn, Fe,and Al) in surface waters of the Northern- and Southern East Atlantic

Surface seawater samples were taken in the framework of the GEOTRACES program on “POLARSTERN” expedition ANT XXIII/1 in the Eastern Atlantic in 2005 to study the distribution of the trace elements Hg (mercury), Pb (lead), Cd (cadmium), Cu (copper), Ni (nickel), Zn (zinc), Co (cobalt), Mn (manganese), Fe (iron), and Al (aluminium). With the exception of Hg, results were compared to earlier datasets from 1989 to 1990. The particulate fraction averaged over the transect was calculated to be 49% for Cd, 23% for Mn and 50% for Fe indicating a release of these TEI's (trace elements and their isotopes) from a leachable SPM fraction in the stored and acidified samples.Total Pb concentrations ranged between 5 and 20 pmol kg^? 1 in 2005 with highest values in the ITCZ (intertropical convergence zone). In 1989 Pb concentrations were twice as high in the region of the ITCZ, while by a factor of 10–15 higher values were obtained in the North Atlantic.Total Cd and Co are dominated, by different seasonal upwelling regimes (Equatorial upwelling, Guinea Dome, Angola Dome).Total Cu, Ni, Fe, Mn and Al show nearly identical concentrations in 1990 and 2005. For total manganese and aluminium strong maxima (3–4 nmol kg^? 1 and 55 nmol kg^? 1 respectively) are observed between 23°N and 0°, while the Fe maximum (6–9 nmol kg^? 1) is located at 7°N. Total Hg concentrations ranged between 0.5 and 4.5 pmol kg^? 1.     

球扁钢等效方法的研究

在进行船体结构强度的计算分析时,需要将球扁钢等效为L型材或T型材进行屈服及屈曲计算。然而,现有的等效转化方法存在较为明显的问题。本文在前人研究基础上,推出两种简化等效方法,并与现有方法进行计算对比,结果表明这两种方法简单方便,精确度高。此外,本文分别使用三种转化方法,运用Mars2000软件计算某船剖面的极限强度。计算结果表明,使用本文提出的等效转化方法一计算船体结构极限强度最合理。     

从人机料法环测分析重大工程项目的质量控制

摘要：从工程项目的决策阶段到实施阶段的整个过程中,影响工程项目质量的因素主要有“人、机、料、法、环、测”等六大方面。文章论述了对这六方面的因素予以严格控制是保证重大工程项目质量的关键。     

浅谈海事船舶管用养修

深入开展海事船舶管用养修工作，为辖区水上安全中心工作提供强有力保障已成为海事船舶管理的重点和难点。介绍了镇江海事局所属船舶基本概况，重点叙述了海事船舶管用养修工作的主要做法。通过船舶管用养护工作的开展，船舶管理长效机制基本形成，船舶良好的技术状态得到保持，素质得到提高，水上突发事件的应急处置能力明显提升。     

Monitoring trace elements (Al, As, Cr, Cu, Fe, Mn, Ni and Zn) in deep and surface waters of the estuary of the Nerbioi-Ibaizabal River (Bay of Biscay, Basque Country)

Deep water samples (in contact with the sediment) were collected at eight different points of the estuary of the Nerbioi-Ibaizabal River (Bay of Biscay, Basque Country), both at low and high tides, during four sampling campaigns (May, September and December 2005 and March 2006). Superficial water was also sampled in March 2006. Temperature, pH, redox potential, dissolved oxygen and electrical conductivity corresponding to each sample were measured in situ at each sampling point using a multiparametric probe. The physico-chemical parameters found are typical of highly stratified estuaries, with an acceptable oxygenation level. After filtering and acidifying the samples, they were analysed by inductively coupled plasma/mass spectrometry (ICP/MS) to simultaneously determine the total concentration of Al, As, Cr, Cu, Fe, Mn, Ni and Zn. Concentrations in the μg kg^− 1 level were found in all cases (c_Cr and c_Ni, 1–10; c_Al, c_As and c_Zn, 10–50; c_Cu and c_Mn, 10–100 and c_Fe, 100–400 μg kg^− 1). A probable net input of Al, Cr, Mn and Zn via the main (Nerbioi-Ibaizabal) and some of the tributary rivers (Galindo, Asua and Gobela) was identified. Evidence of a common source of Al and Zn to the estuary was found. Correlation analysis of data revealed connections between variables (concentration of Cu, Fe and As with salinity, as well as c_Al with c_Zn, c_Cu with c_Fe, c_As with c_Fe, and c_As with c_Cu). Principal Component Analysis (PCA) of data allowed the samples to be grouped according to sampling campaign, with two principal components accounting for 62% of the total variance. In addition, plots of element concentration against salinity suggested a conservative behaviour for As, Cu and Fe and a non-conservative one for Cr. Not clear mixing behaviour was observed for the rest of elements.     

节能环保型抗沉式铝合金游艇的研制

叙述了南太湖区域某企业新近研制了一艘集节能、环保、环境友好型为一体的抗沉式铝合金游艇,其上的关键技术包括:游艇抗沉措施、降温系统的工作原理和实效、以及铝合金船体制作的焊接技术要求和强度计算原则等。     

Specialization and economic impact of the ports of Montreal,Quebec, Saint John,and Halifax

Specialization in cargoes and forelands is defined for the ports of Montreal, Quebec, Saint John, and Halifax using a variation of the location quotient. Economic impact is also defined using the location quotient. All ports are shown to have some degree of specialization; whereas, Saint John and Halifax have relatively greater economic impact. It is suggested that the four ports should be encouraged to develop their specializations. However, are the benefits to the shipping industry in following such a policy outweighed by the losses to the local economies because investment in certain ports does not take place?     

Specialization and economic impact of the ports of Montreal, Quebec, Saint John, and Halifax

Specialization in cargoes and forelands is defined for the ports of Montreal, Quebec, Saint John, and Halifax using a variation of the location quotient. Economic impact is also defined using the location quotient. All ports are shown to have some degree of specialization; whereas, Saint John and Halifax have relatively greater economic impact. It is suggested that the four ports should be encouraged to develop their specializations. However, are the benefits to the shipping industry in following such a policy outweighed by the losses to the local economies because investment in certain ports does not take place?     

库码头技术在推动港口绿色低碳集约智能化发展中的应用

针对现有港口过多依赖和占用土地及岸线资源、作业效率低下、环境污染严重、智能程度难以提高等问题,采取将常规港口三要素——码头、库场和装卸机械集成为一体的"库码头技术",可在相当程度上解决这些问题,从而转变港口建设方式,推进港口向绿色、低碳、集约、智能化方向快速迈进。     

刚果(布)黑角矿业港总平面布置

针对复杂水动力环境条件下港口平面布置,基于刚果(布)黑角矿业港项目,根据对波浪、海流以及泥沙等主要影响因素的深入分析,提出两个平面方案,并通过方案比选及模型试验研究,采用对周边水动力环境影响小、易于起步、投资回报高的单侧防波堤疏浚土回填造地的双港池平面布置方案。结果表明,对于受复杂水动力影响的刚果(布)及临近海域港区的平面布置,应重点考虑波浪的掩护、沿岸输沙以及波浪和海流对船舶的共同影响。