高应变法确定大直径混凝土管桩的承载力

在缺少大直径混凝土管桩静载试验的情况下,现在普遍采用了动测试桩的方法确定大管桩承载力。文中提出采用CASE法和CAPWAPC法相互比较来确定大管桩承载力的方法。     

聚合物改性水泥混凝土路面的施工工艺

结合实际施工经验，对聚合物改性水泥混凝土路面的施工准备，混合料拌和、运输、摊铺及养生等环节进行了论述，提出了在施工中应注意的事项和完整的施工工艺方案。实践证明，聚合物改性水泥混凝土路面性能良好．成本较低，符合环境友好、资源节约型路面的理念，具有良好的社会效益和经济效益。     

数字技术在船用频率捷变雷达信标中的应用

数字技术正渗透到一切电子设计部门,特别是雷达领域。本文叙述了数字技术在频率捷变雷达信标中的应用,它可克服模拟电路的局限性,特别是采用微处理机后,拓展了增强雷达信标功能的途径,如旁瓣的有效抑制、信标机状态的自检及性能自测并遥报、信标机的非实时应答响应、电源的自动搜索控制等。     

宜万铁路宜昌长江大桥主桥创新技术研究

宜万铁路宜昌长江大桥主桥采用(130 2×275 130)m连续刚构柔性拱组合结构,桥型方案为铁路桥梁首次采用,设计中针对结构构造、受力、施工等特点,采用了多项技术创新,包括桥梁结构、构造和材料等方面。     

和谐交通的伦理构建:系统、结构、层次

构建"和谐交通"是系统性的价值目标,需要以和谐伦理为导向,从宏观上审视现代交通关系的结构及其特征,研究交通主体之间、交通客体之间、交通主客体之间的基本关系及其状态,通过一系列调整优化,使之不断地从冲突走向和谐。     

重庆石板坡长江大桥复线桥总体设计

重庆石板坡长江大桥复线桥是主跨330 m的世界第一大跨径梁桥,大桥主跨跨中103m梁段采用了钢箱梁结构,这样有效地降低了主梁的弯矩和剪力,正是采取了这样的措施,才使得如此大跨径的桥梁在技术和造价上都切实可行。     

钢管拱肋微膨胀混凝土压注技术

拱肋压注混凝土施工在拱桥施工中是一个很重要的环节。介绍拱肋混凝土的压注工艺和方法,包括选材、混凝土配合比的设计,混凝土的拌制、运输等。可供借鉴。     

总纵强度耦合作用下船体板架振动计算

船体在海上营运时，船体产生中拱状态弯曲和中垂状态弯曲，所以船体板架是处在复杂弯曲状态。以往船体板架振动计算都忽略了这种影响。本文讨论用有限元方法和原理应用于这类计算，推导了板架局部振动的计算方法，给出了计算实例。通过计算表明，本文方法可用于实际，为舰船振动校核计算提供了手段。     

Pb and Pu in the Northeast Water Polynya, Greenland: particle dynamics and sediment mixing rates

Distributions of the radionuclides ²¹⁰Pb and ^239,240Pu in sediment cores from the Northeast Water Polynya, Greenland, showed that these nuclides reached depths of 5–15 cm by particle mixing and sediment accumulation. End-member average values of the particle mixing coefficient and sediment accumulation rate were 0.13 cm² y⁻¹ and 0.06 cm y⁻¹, obtained from the ²¹⁰Pb profiles by assuming that each process is dominant relative to the other. Both ²¹⁰Pb and ^239,240Pu were measured on four cores; using the Pu data to constrain mixing rates produced corrected sediment accumulation rates that were 20–80% of the values calculated by neglecting mixing. Organic carbon burial in the polynya sediments was ≤0.4 mmol m⁻² d⁻¹, based on measured POC values at depth in the sediments and sediment accumulation rates corrected for mixing. This value is about 1% of the independently measured POC flux leaving the euphotic zone and compares with benthic carbon remineralization rates of 7% calculated by others from O₂ uptake in the sediments.The inventories of excess ²¹⁰Pb in the sediments ranged from 6 to 28 dpm cm⁻². Relative to the atmospheric input of ²¹⁰Pb and in situ production from decay of ²²⁶Ra, approximately 5 dpm cm⁻² of ²¹⁰Pb was being removed from the water column. The difference between the removal from the water column and sediment inventories suggests a net import of ²¹⁰Pb to the polynya. This may occur by input of dissolved ²¹⁰Pb from offshore waters or by input of ²¹⁰Pb carried by sea ice. Particulate matter in land-derived fast ice adjacent to the polynya contained 330 ± 14 dpm of excess ²¹⁰Pb g⁻¹. If particles transported in sea ice are comparable to those extracted from fast ice, then sea ice transport into the polynya followed by melting may be an important source of excess ²¹⁰Pb to the area. Fast ice also may contribute ²¹⁰Pb if portions break off and melt within the polynya, as occurred in 1993.     

C70型敞车的研制

介绍了C70型敞车的开发过程、结构参数、性能特点以及试验情况。