北京新机场线高架地段双块式无砟轨道结构设计

北京新机场线是我国首条最高速度达160 km/h的地铁线,轨道结构采用双块式无砟轨道,高架地段首次采用取消底座结构设计,为了保证轨道结构的安全可靠,有必要对无砟轨道道床结构进行结构选型及配筋设计。通过建立高架地段无砟轨道结构的有限元模型,对道床板板长、板宽、板厚进行了选型分析。针对无砟轨道无底座设计方案,考虑了列车荷载、温度梯度、桥梁挠曲3种主要荷载类型,提出了荷载组合方案,研究其关键控制因素,对道床板进行了配筋设计及检算。通过参数比选,完成了道床板的尺寸参数选择;在3种荷载类型中,温度梯度在道床板中引起的弯矩值最大,在设计荷载中占据主导因素,合理减小道床截面高度可有效降低温度梯度作用;道床板配筋应以控制裂缝为原则进行设计。     

新能源汽车制造过程高压安全检测的研究

为充分保证新能源车辆生产制造环节中,各高压部件与车身电平台、高压负载回路及充电回路的高压电气安全,从而保障整车电气安全质量及车辆使用者的安全,建立了 一套系统化的整车装配过程高压安全检测工艺方案.研究分析了电气化转型趋势下,车辆高压安全对整车制造环节的检测需求和影响.同时分析了各检测项的工艺检测条件,及其对整车装配工艺...     

雨水利用与城市防洪初探

随着中国城市化进程的加快,近年来各地暴雨过后大面积积水的新闻也不绝于耳。在中国城市的开发建设中,如何将雨水利用与城市防洪技术相结合为城市的发展服务呢?该文对国内外雨水利用与城市防洪技术作了总结,并以上海嘉定新城雨水利用工程为案例,通过理论计算与工程实例来说明城市雨水利用的经济效益和实施的可行性,寄予对国内其他城市的建设起到借鉴作用。     

倾斜突出煤层排放设计方法优选

为选择安全有效的瓦斯排放措施,降低瓦斯压力对瓦斯突出隧道的影响,针对隧道穿越多层距离较近的倾斜突出煤层,以改建铁路重庆至贵阳扩能改造工程新凉风垭隧道为背景,采用对比分析法,研究分析了3种瓦斯排放设计。综合考虑施工便利程度、通风及隧道衬砌结构稳定性等因素,确定了新凉风垭隧道在穿越煤系地层地段距离较近的K7,K8和K9 3层煤时,采用排放方式1（即在垂直掌子面上打排放孔的方式进行排放, K8,K9 2层煤1次排放,再单独排放K7煤层,排放孔布置形式为矩形行列结构）,此方式适合穿越多层距离较近的倾斜突出煤层的瓦斯排放。     

交通可达性对居住地选择的影响--以成都市为例

为了解新型城镇化战略下大城市中心区居民外迁至卫星城时的居住地选择行为特征及偏好，选取卫星城居住地周边学校、医院、商业设施、轨道交通车站及到中心区交通可达性作为主要变量。根据家庭成员组成特征将样本家庭划分为5类，对比分析不同家庭居住地选择行为特征及偏好。结合家庭社会经济属性形成了一套包含8种情景的正交设计组合问卷，对成都市中心区居民进行意愿调查，并建立Logit模型对居住地选择行为进行分析。结果表明，学校、医院等主要服务设施的交通可达性及家庭自身属性均对中心区居民外迁行为存在显著影响，同时定量分析各变量对居民选择外迁意愿的影响程度，最后提出有助于中心区人口疏解到卫星城的交通政策和措施建议。     

How much is too much for tolled road users: Toll saturation and the implications for car commuting value of travel time savings?

The current practice of forecasting the demand for new tolled roads typically assumes that car users are prepared to pay a higher toll for a shorter journey, and they will keep doing so as long as the toll cost is not higher than their current value of travel time savings. Practice ignores the possibility that there could be a point when motorists stop driving on toll roads due to a toll budget constraint. The unconstrained toll budget assumption may be valid in networks where the addition of a new toll road does not result in a binding budget constraint that car users may have for using toll roads (although it could also be invoked for existing tolled routes through a reduction in use of a tolled route). In a road network like Sydney which offers a growing number of (linked) tolled roads, the binding budget constraint may be invoked, and hence including additional toll links might in turn reduce the car users’ willingness to pay for toll roads to save the same amount of travel time. When this occurs, car users are said to reach a toll saturation point (or threshold) and begin to consider avoiding one or more toll roads. Whilst toll saturation has important implications for demand forecasting and planning of toll roads, this type of behaviour has not been explored in the literature. We investigate the influence that increasing toll outlays has on preferences of car commuters to use one or more tolled roads as the number of tolled roads increases. The Sydney metropolitan area offers a unique laboratory to test this phenomenon, with nine tolled roads currently in place and another five in planning. The evidence supports the hypothesis that the value of travel time savings decreases as a consequence of toll saturation.     

Seaport Development and Coastal Management Programs: A National Overview

Oysters have been harvested on the east coast of Australia for many thousands of years. Coastal Aboriginal communities used the extensive estuarine oyster resource and may have farmed oysters by establishing shell cultch beds in shallow areas of estuaries. The British colonization of Australia commenced in 1788 and oysters were initially used for food and production of lime. Concerns about unsustainable exploitation led to introduction of legislation that directed the oyster industry to aquaculture in 1884. Translocation of oyster stock for fattening, from New Zealand to Australian east coast estuaries, was encouraged. Here evidence is presented that this activity resulted in “mudworm disease” appearing in oyster farming estuaries on the Australian east coast between 1880 and 1900. The pandemic permanently destroyed natural sub-tidal oyster reefs and forced the oyster industry to adopt avoidance farming techniques including intertidal farming to cope with mudworm.     

兰州市区至兰州新区中快线建设方案研究

对兰州市区至兰州新区中快线建设条件分析,研究其合理的建设方案。通过对中快线在兰州至兰州新区3条规划交通廊道的作用和定位分析,采用交通量预测、调查选线、经济估算等方法,研究了中快线建设所涉及的若干关键技术问题,指出中快线建设是十分必要的,其南端宜同时建设3条连接线与兰州市区连接,北端应与兰州新区南绕城及经十三路连接,主线宜采用120km/h设计速度、双向六车道标准,可采用城市快速路或高速公路模式建设,且通道内具有预留轻轨建设条件。     

"新定额"在特殊结构隧道中的应用与探讨

新编《铁路隧道工程预算定额》（铁建设[2004]47号文，以下简称“新定额”）主要适用于使用小型机具钻爆法施工的新建和改（扩）建单、双线隧道工程。此文结合某铁路隧道概算编制实践，主要阐述“新定额”在三线、四线、燕尾式及岩溶隧道中的应用，为类似隧道工程的概算编制提供参考意见。     

水泥搅拌桩新型施工工艺的应用

着重介绍了在采用水泥搅拌桩进行软土地基处理时一些新型施工工艺的应用,并将新型施工工艺和传统工艺进行了比对,总结了新型施工工艺条件下一些主要技术参数.