Evaluation of CO2 emissions from railway resurfacing maintenance activities

This paper is the world first to investigate the CO₂ impact of railway resurfacing in ballasted track bed maintenance. Railway resurfacing is an important routine maintenance activity that restores track geometry to ensure safety, reliability and utility of the asset. This study consisted of an extensive field data collection from resurfacing machineries (diesel-engine tamping machines, ballast regulators and ballast stabilisers) including travel distances, working distances, fuel consumption and construction methodologies. Fuel consumption was converted to a kg CO₂/m using the embodied energies of diesel. Analyses showed that tamping machines emitted the highest CO₂ emissions of the resurfacing machineries, followed by ballast regulators and ballast stabilisers respectively. Tamping machines processed 4.25 m of track per litre of diesel, ballast regulators processed 6.51 m of track per litre of diesel and ballast stabilisers processed 10.61 m of track per litre of diesel. The results were then compared to previous studies and a rigorous parametric study was carried out to consider long-term resurfacing CO₂ emissions on Australian railway track. The outcome of this study is unprecedented and it enables track engineers and construction managers to critically plan strategic rail maintenance and to develop environmental-friendly policies for track geometry and alignment restoration.     

采用“一刀成型法”加工直齿圆锥齿轮时切削角的误差分析与修正

在铁路柴油机检修非标设备制造中,在铣床上试验成功了直齿圆锥齿轮"一刀成型法"的加工工艺,可满足精度要求,并提高了生产效率。根据收集的多组加工数据,利用工程数学方法,分析切削角产生误差的原因,推导出修正经验公式,进一步提高了加工精度。     

道桥防水施工中路基面处理技术和管理的探讨

在道桥防水方面的工程建设中,路基面处理是否得当是道桥防水是否成功的关键,对道桥防水施工过程中路基面处理技术和管理问题进行探讨和研究.     

广西地区高速公路沥青路面养护措施评价研究

针对目前广西地区高速公路沥青路面养护状况,文章依托实体工程,通过路面养护数据和使用性能检测数据的收集、整理和分析,对微表处、不同厚度的铣刨重铺等常用沥青路面养护措施的使用效果进行评价,其对广西地区高速公路沥青路面养护方案的制定具有借鉴意义。     

A bottom-up solution for the multi-facility optimal pavement resurfacing problem

Transportation infrastructure management has been a subject of growing economic importance in recent years due to the magnitude of agency expenditures. Increasingly sophisticated methods have been developed to model pavement deterioration and solve for optimal management strategies. However, it is unclear whether these more complex methods are providing more useful results. This paper presents a simple approach for optimizing the frequency and intensity of resurfacing for multiple highway facilities. It builds upon existing optimization methods for the single-facility, continuous-state, continuous-time problem and corresponding results, which include a threshold structure for optimal solutions. This threshold structure allows for mathematical simplifications and for a straightforward optimization approach to be applied to the multi-facility case. The approach is bottom-up rather than top-down, preserving facility-specific features to develop informative budget allocation results. Application of the approach in a case study indicates that solutions are likely to be robust to deterioration model uncertainty, which is consistent with previous facility-level findings. In addition, the methodology is shown to be robust to the form of the deterioration model.     

沥青路面铣刨料的性能评价

结合干线公路养护维修工程,对再生铣刨料的回收沥青性能以及级配组成进行了全面的试验分析,并提出了进行再生料设计时需要考虑的沥青铣刨料相关性质,为研究与提高再生技术提供参考。     

不锈钢铣削力的试验研究

采用多因素正交试验法进行了不锈钢铣削试验,通过测力系统测量了铸造不锈钢倾斜面球头刀铣削的铣削力,得出了预测铸造不锈钢CrlM18Ti9的铣削力经验公式,并验证了公式的有效性.应用该公式可以提前对选定铣削参数的铣削力进行估计,避免了铣削力过大引起的刀齿损坏.有关分析结果对铣刀的设计及不锈钢铣削参数的优化选择有一定的参考价值.     

铣削大平面时机床主轴角度的调整

在铣削汽车发动机和变速器的几个大平面时，由于受机床主轴的回转精度以及夹具精度的影响，加工中易出现啃刀、刮伤等现象。为避免发生啃刀、刮伤等现象，提出应将机床为轴调整一个角度，并建立了调整角度的经验公式。     

两水隧道软岩铣挖法施工技术

铣挖法是适合软岩隧道施工工艺的一种开挖方法.文章以两水软岩隧道为例,介绍了铣挖机工艺特点、采用铣挖机的隧道施工方案,从施工安全、施工质量、施工进度等方面进行了钻爆法和铣挖法的分析对比.实践结果表明,铣挖法与预裂爆破相结合是比较安全、经济的施工方法.     

共轭螺旋曲面的啮合间隙处理

螺杆泵螺相的实际加工，必须考虑共轭螺杆间的均匀间隙要求，以保证螺杆泵的可靠运行。本文对螺杆端面型一为复杂组合曲线，通过对组合曲线作磨光处理，利用构作等距曲面的方法，对给定的间隙要求命同了计算加工螺杆的盘铣廓形的计算方法。