高地应力软岩隧道圆形断面扩挖施工围岩及支护受力特征研究

针对高地应力软岩隧道开挖时围岩大变形问题,以某隧道圆形扩挖段为背景,采用三台阶法施工和3层初期支护+小导管注浆+二次衬砌的复合结构支护,并通过现场监测、数值模拟和理论计算研究开挖过程中的围岩变形及支护结构受力。结果表明:上、中台阶开挖时的隧道围岩变形速率较大,在仰拱封闭和第3层初期支护施作完成后,隧道变形趋于稳定;采用3层初期支护结构可有效改善隧道周边围岩应力,3层初期支护基本都是受压结构,拱腰和边墙处竖向应力最大,拱顶处水平应力最大;二次衬砌拱腰、拱顶、拱脚和边墙处安全系数均大于规范要求,保证隧道结构安全。     

TOA FOR RESECTION OF BULBAR CERVICAL VENTRAL COMPRESSION LESION

Ｉｔｉｓｗｅｌｌｋｎｏｗｎｂｙｎｅｕｒｏｓｕｒｇｉｓｔｓａｎｄｏｒｔｈｏｐｅｄｉｓｔｓｔｈａｔｂｕｌｂａｒ－ｃｅｒｖｉｃａｌｄｏｒｓａｌｃｏｍｐｒｅｓｓｉｏｎｌｅｓｉｏｎｓｃａｎｂｅｒｅｓｅｃｔｅｄｖｉａｐｏｓｔｅｒｉｏｒａｐｐｒｏａｃｈｅｓ，ｂｕｔｉｔｉｓｄｉｆｆｉｃｕｌｔｔｏｒｅｓｅｃｔｔｈｅｖｅｎｔｒａｌｃｏｍｐｒｅｓｓｉｏｎｌｅｓｉｏｎｓ．Ｗｉｔｈｔｈｅｉｍｐｒｏｖｅｍｅｎｔｏｆｉｍａｇｅ，ｍｉｃｒｏｓｕｒｇｉｃａｌｔｅｃｈｎｉｑｕｅａｎｄｉｎｓｔｒｕｍｅｎｔｓ，ｔｈｅｒｅｓｅｃｔｉｏｎ…     

三点检查逻辑对区间轨道电路分路不良的防护研究

将联锁的三点检查逻辑应用到区间中,按轨道“占用出清顺序逻辑检查”的方法,对发生分路不良的轨道区段作出判断,并通过控制后续区段轨道电路编码的方法,实现对追踪列车的防护.这种方法完全通过逻辑处理实现,是一种简便易行的轨道电路分路不良防护措施.     

国庆六十周年甘肃彩车平台结构设计与分析

通过对国庆六十周年甘肃彩车平台进行结构设计与分析,为三类汽车底盘改装特种车辆提供借鉴。     

漓江旅游客船防抗雷雨大风的稳性分析

文章针对漓江旅游客船易受雷雨大风袭击的事故特点,分析了雷雨大风的形成原因,探讨了航向、风向、流向对航行安全的影响,建立了漓江旅游客船防抗雷雨大风的稳性衡准式,并提出了客船防抗雷雨大风的注意事项。     

电解法处理船舶压载水的可行性研究

通过实验室模拟的一套电解装置处理系统,对电解海水法能否处理船舶压载水,以及电解海水法处理船舶压载水造成二次污染的一些争议进行了实验验证。探索了电解法处理船舶压载水的有效性和在船舶上实施的可行性。     

国际渔业管理中的生态标签制度

响应可持续性环境发展的号召,渔业生态标签制度应运而生。发展中国家最大的疑虑是担心形成潜在的贸易壁垒。世界粮农组织于2005年达成《海洋捕捞渔业鱼和渔产品生态际签国际准则》,希望给所有已经或者计划实行生态标签制度的国家以最大的信心和帮助。     

册镇海底管线沿线海床冲刷原因及冲刷趋势研究

海床冲刷可能导致海底输油管线裸露悬空,影响其运营安全。文章针对册镇海底输油管线沿线海床的冲刷现象,利用杭州湾大范围海域潮流数学模型和海床冲淤计算方法,分析了造成海床冲刷的原因,预测了冲刷的发展趋势。研究结果表明:册镇海底输油管线沿线海床冲刷主要与新泓口围垦的局部挑流及金塘大桥的阻水作用有关。随着规划围垦工程的实施,沿线部分海床还将进一步冲刷。     

How much can public private partnership really do for urban transport in developing countries?

A few cities in some of the larger developing countries in Latin America and Asia have made increasing use of multi-year concessions or franchises, competitively awarded to private companies, for construction and operation of urban transport infrastructure and for provision of public transport services. In view of the strong prospective growth of developing-country cities with large transport needs, and the rise in the emerging economies of potential new sources of private capital, it is important to see how effective PPP has so far been in this area. The experience is analyzed principally by thorough comparative review of what has actually happened for some of the main users to date: Bogotá, Santiago, São Paulo, Seoul, and several cities in both China and India. Despite delays and mistakes that have been made in development of most of the projects, the overall results, already delivered and in prospect, are very positive and urban public transport is benefiting substantially, with significant side effects on poorer people's access to work and to services, air pollution levels and road accident rates. The widest and most important advantage of the PPP arrangements, as compared with more conventional short-term contracting, is found to be the innovations, technical and managerial, developed, and, in particular, the mutual capacity building of the countries' private and public sectors and their more effective interaction. The experience in the six countries covered suggests that other developing-country cities may be best assisted to develop sound urban transport PPPs more rapidly through provision of help on chosen items among 7 elements that have proved particularly crucial but sometimes weak in the projects reviewed: Civic consultation systems, Land-use/Transport strategic planning, Land/property market management, Monitoring systems, Progressive policies, Economic regulation, and Public institutional framework for PPPs.     

长江南京以下12.5 m深水航道一期工程白茆沙水道工程局部冲刷试验研究——Ⅰ：模型设计

长江南京以下12.5 m深水航道一期工程白茆沙水道工程局部冲刷研究工作表明:1)采用局部正态模型研究潮汐河口工程局部冲刷问题是可行的;2)试验水力条件的选择、模型边界的确定以及模型的整体变坡等是将局部正态模型应用于潮汐河口工程局部冲刷问题研究需解决的关键技术问题;3)白茆沙水道工程局部正态模型较好地复演了目标试验水力条件,具备开展进一步试验的条件;4)提出了简便易行且效果良好的模型边界确定方法。