快速公交与其他公共交通方式比选及融合发展

常见的大中运量公共交通方式包括城市轨道交通、快速公共汽车(Bus Rapid Transit,BRT)、有轨电车。BRT凭借其灵活性和适应性,在运能、服务水平等方面与城市轨道交通、有轨电车具有一定的可比性。因此,三者常常成为城市公共交通骨干网络选型比较的对象。与城市轨道交通相比,BRT处于辅助地位,配合完善公共交通骨干网络。与有轨电车相比,BRT的灵活性、经济性较优,服务水平、环保水平、形象提升方面略逊。公共交通系统规划应充分评估城市条件、未来发展潜力,在不同客流走廊配置不同的公共交通方式;合理选取并融合发展城市轨道交通、有轨电车和BRT等多种方式,构建立体、完备的公共交通体系,满足居民多样化的出行需求。

铁路桥梁桩基优化计算方法研究

研究目的:铁路工程总承包项目设计时,桥梁桩基础体量庞大、控制因素繁多,存在较大优化空间。本文从桩基类型、桩长、桩身配筋等方面进行研究,在满足桩基设计安全和质量要求的前提下,提出桩基优化计算方法。研究结论:(1)构建了旋挖挤扩灌注桩的具体计算方法和流程,增加了桩基类型的比选方案;(2)提出了地震荷载下桩长优化的联动迭代算法,准确计算出桥墩摩擦桩基础的最优桩长;(3)提出等效地质参数法模拟上覆淤泥层较厚时的桩基计算,优化桩身配筋量效果明显;(4)提出了三次坐标转换的计算方法,解决了桥墩与基础产生扭角时计算精度不够的问题;(5)以上算法纳入桩基计算系统,大规模应用于多条铁路总承包项目,实现了铁路桥梁桩基础的精细化计算,满足了高经济性、高安全性与高质量的设计需求,为各项目节约了0.5亿~1.8亿不等的工程造价,可为铁路桥梁桩基结构优化设计提供借鉴。

Coal washing improvement by determination of optimal mixture of feed blends

Coals from different mines are feed in the Zirab plant without any control on weight percentage blending of them. Three major coal types of different ranks (Kiasar, Lavidj and Karmozd) were blended in various proportions to find an optimum condition in flotation circuit in Alborz Markazi coal washing plant. Flotation tests were conducted for prepared blended coal samples to assess floatability of various coal samples. In this paper, mixture design as a statistical method was used to optimize coal blend to increase recovery and grade in Zirab coal washing plant. The statistical analysis showed that the weight percent blending of different coals and interaction between Lavidj and Karmozd regions coal had significant effects on the coal recovery. The optimum condition of 95% recovery and 12% ash content could be reached with 10%, 20%, and 70% blending portion of Kiasar, Lavidj and Karmozd regions coal, respectively.