天津市张贵庄污泥处理工程工艺选择

天津市张贵庄污泥处理工程采用槽式高温好氧发酵工艺处理天津市张贵庄污水处理厂产生的污泥,处理规模为300 t/d(含水率为80%),处理后污泥可作为营养土进行土地利用,也可填埋。介绍了天津市张贵庄污泥处理工程工艺选择遵循的技术政策、标准及原则,以期为以后类似工程工艺方案选择提供有益借鉴。     

贵阳市西南环线二期总体方案

贵阳市西南环线二期位于城市中心区东南部,地形起伏大,属于旧路拓宽改建项目。针对项目特点,对总体思路、方案布置等方面进行了介绍,为类似山区城市道路方案研究提供参考。     

The effect of slow zones on ridership: An analysis of the Chicago Transit Authority “El” Blue Line

Transit agencies frequently upgrade rail tracks to bring the system to a state of good repair (SGR) and to improve the speed and reliability of urban rail transit service. For safety during construction, agencies establish slow zones in which trains must reduce speed. Slow zones create delays and schedule disruptions that result in customer dissatisfaction and discontinued use of transit, either temporarily or permanently. While transit agencies are understandably concerned about the possible negative effects of slow zones, empirical research has not specifically examined the relationship between slow zones and ridership. This paper partially fills that gap. Using data collected from the Chicago Transit Authority (CTA) Customer Experience Survey, CTA Slow Zone Maps, and, the Automatic Fare Collection System (AFC), it examines whether recurring service delays due to slow zones affect transit rider behavior and if the transit loyalty programs, such as smart card systems, increase or decrease rider defections. Findings suggest that slow zones increase headway deviation which reduces ridership. Smart card customers are more sensitive to slow zones as they are more likely to stop using transit as a result of delay. The findings of this paper have two major policy implications for transit agencies: (1) loyalty card users, often the most reliable source of revenue, are most at risk for defection during construction and (2) it is critical to minimize construction disruptions and delays in the long run by maintaining state of good repair. The results of this paper can likely be used as the basis for supporting immediate funding requests to bring the system to an acceptable state of good repair as well as stimulating ideas about funding reform for transit.     

双控道岔联系电路的设计与实现

在个别站场间,为节省占地面积或受其他因素制约,两站的联锁区是由一组双动道岔隔开。若其中一站为计算机联锁控制,另一站为6502电气集中控制,依据相关设计规范,设计出一套计算机联锁车站与6502电气集中车站利用渡线隔开时的结合电路。该结合电路安全可靠,未改变原有电路定型结构。经过联锁模拟实验,该设计方案合理可行。     

Is the provision of park-and-ride facilities at light rail stations an effective approach to reducing vehicle kilometers traveled in a US context?

Park-and-Ride (PNR) facilities are a commonly used means of making a transit system more widely available. However, given that a PNR passenger must drive for part of the trip, this approach to transit provision has an ambiguous influence on vehicle kilometers traveled (VKT). The impact of PNR on VKT is highly dependent of how PNR users would choose to travel if the PNR facilities were not available. Given that this issue has received little attention in a US context, we use the light rail system in Charlotte, North Carolina as a case study to examine the potential impact of PNR removal on VKT. Using a travel survey of PNR passengers, we estimate the VKT currently generated while driving to and from the rail stations and then estimate how VKT would change under various PNR removal scenarios that assume different behavioral responses. We find that, under the most realistic scenarios, PNR removal would lead the average PNR passenger to increase her driving by 8–15 VKT per round trip.     

U71 Mn 50 kg·m-1普通碳素钢钢轨疲劳裂纹扩展速率试验研究

根据室内对U71Mn50kg·m-1普通碳素钢钢轨按三点弯曲标准进行的试验,测定该钢轨的疲劳裂纹扩展速率,即裂纹扩展深度a及其对应的循环次数N值。利用中值法求得裂纹扩展深度对循环次数的微分值。根据断裂理论求得相应的裂纹前沿应力强度因子幅度ΔK。根据Paris公式,对以上两值取自然对数进行线性回归分析,确定该公式中U71Mn50kg·m-1普通碳素钢钢轨疲劳裂纹扩展速率的两个材料常数C为3 8771×10-12,m为3 6343。     

天津地铁既有车站改建设计

通过对天津地铁1号线既有车站改建的实例分析,论述了既有地铁车站改建的设计方法,提出了对于其他地铁既有项目也会面临的局部改建和设备更新的问题。地铁车站的设计应以预测规定年限的客流量为依据,具有科学性、可行性、经济性和前瞻性。     

Dynamics of the railway track and the underlying soil: the boundary-element solution, theoretical results and their experimental verification

A combined finite-element boundary-element method is presented in detail to calculate the dynamic interaction of the railway track and the underlying soil. A number of results are shown for ballasted and slab track, demonstrating the influence of the stiffness of the soil and the rail pads on the vertical compliance of the track. The compliance of the track is combined with a simple model of the vehicle giving the transfer function of vehicle-track interaction. An experimental verification of the theoretical results is achieved by harmonic and impulse excitation with and without static (train-) load and by combined measurements of train-track-soil interaction. A clear vehicle-track resonance is found for the slab track with elastic rail pads and for higher frequencies at highspeed traffic, the dynamic axle loads due to sleeper passage are reduced.     

软土地基地段动态设计的理念和方法

简要介绍了秦沈客运专线软土和松软地基处理方案和路基工后沉降量控制标准，通过秦沈客运专线动态设计实践，强调在高速铁路建设过程中开展动态设计的意义，并从沉降断面布置、设备选择、观测频度、数据处理方法、数据分析的基本原理和应用等方面，系统介绍动态设计的方法和步骤。     

城市高架轨道交通景观评价体系研究

研究目的:目前国内对于城市高架轨道景观评价的研究尚处于探索阶段,还没有成熟的指标体系及评价方法,为此需首要建立一套较为客观、简捷、实用,又能得到专家和公众认同的景观评价体系。研究方法:本文选用“目标—指标层次结构”模式,就是AHP层次分析方法,从动态景观和静态景观2个方面去构建城市高架轨道交通景观评价体系,并以重庆轻轨2号线中的2个有代表性的区段景观,对该体系进行验证。研究结论:经实例验证,本文建立的城市高架轨道交通景观评价体系能够具体体现出高架轨道景观的差异性,并能反映具体差异点及差异程度。可明确量化地反映高架轨道交通的景观评价等级和其中单项指标的景观等级,并具有可比性,其结果能准确、客观地反映城市高架轨道交通景观的实际情况,方法简单易行,具有实用性。