Scientific and Technological Innovation and Operation related Issues for Island Tunnel of Hong Kong Zhuhai Macao Fixed Link Project（港珠澳大桥岛隧工程建设的科技创新和 运营后应关注的若干问题）

The author explains why a giant undersea immersed tube tunnel was selected for the sea area of the main channel of the east side of the Hong Kong Zhuhai Macao Fixed Link Project, instead of employing a bridge or shield tunnel; and summarizes several domestic and international leading innovative technologies applied in the island tunnel construction of the Hong Kong Zhuhai Macao Fixed Link Project, including the use of huge self stabilized steel cylinders as retaining structure of foundation pits for constructing the artificial islands, the large area and ultra deep "sand compaction pile (SCP) composite foundation" reinforcement technology, "semi rigid segment joints", "sandwich" steel RC combined inverted trapezoid closure joints, and crack control and anti corrosion/durability design for RC tube structure. All these technologies reflect Chinese wisdom and Chinese speed. The author also points out some technical issues to which attention should be paid after the immersed tube tunnel of the project is put into operation: （1） Will the post construction settlement and differential settlement of the immersed tube tunnel further develop after the project is open to traffic? How much is the final convergence value? If it exceeds the limit, what control measures should be taken?（2） How to deal with the issue that the joints of large/small elements or segments are open? How to ensure that all the large and small joints between segments of the tube are "watertight"? Furthermore, the author presents some suggestions and control measures: （1） For excessive post construction settlement (especially differential settlement) spotted on large joints, it is suggested to incorporate "micro disturbance grouting" for post treatment. （2） If a joint opens under the excessive positive bending moment at the floor slab, it is believed that the open joint on the floor slab can be closed again by cutting off some prestressed tendons in the roof slab of the segment to reduce the positive bending moment of the section.     

Research Progress and Prospect on Dynamic Response of SFT Structures(悬浮隧道结构动力响应研究进展与展望)

Construction of submerged floating tunnel （SFT） is one of the major solutions for fjord crossing projects and deep sea crossing projects in the future. Aimed to solve the key problems in SFT construction, the authors present an overview on the progress of the researches made in China and other countries in recent years on cross section of SFT, dynamic response of SFT segment structure, vortex induced vibration of anchor cable, testing technique and applicability of SFT, summarize the critical problems in the dynamic response research of SFT structures and make prospect on the trend of further SFT research. Conclusions are drawn as follow: (1) In the aspect of cross section design, SFT with ear shaped or elliptical cross section has good stability in the complex environment of flowing water, with factors comprehensively considered, such as cross section of SFT segment structures, buoyancy weight ratio and layout. (2) In the aspect of dynamic response of structures and anchor cables, the current research methods are mainly based on theoretical derivation and numerical simulation, and poorly rely on model based testing technique; therefore, it is necessary to perform model tests under combined loads from the environment, traffic and SFT, for mutual check between the theoretical analysis and numerical model. (3) In the aspect of applicability, it is necessary to build small SFT in feasible water conditions to make research on the physical SFT in the static waters, to identify problems and to lay a foundation technically for building large SFTs in the complex sea conditions.     

Representative Projects and Development Trend of Underwater Shield Tunnels in China（我国水下盾构隧道代表性工程与发展趋势）

In the 21st century, the underwater tunnels have advanced rapidly in China. A large number of projects, completed or ongoing, have greatly promoted the advancement of underwater shield tunnel technologies in China and in the world. The development history of the underwater tunnels in China is summarized, and the technical challenges and breakthroughs encountered and achieved during the construction of many tunnels are presented, as represented by Nanjing Yangtze River Tunnel and Shiziyang Tunnel of Guangzhou Shenzhen Hong Kong High speed Railway. The characteristics and challenges of some representative underwater tunnels during construction, including Road Railway Yangtze River Tunnel in Sanyang Road, Shiziyang Tunnel of Foshan Dongguan Intercity Railway, Yangtze River Tunnel of Suzhou Nantong UHV Power Transmission and Transformation Project; and projects to be constructed, such as Pearl River Estuary Tunnel of Shenzhen Maoming Railway, Shantou Bay Subsea Tunnel of Shantou Shanwei High speed Railway, and Nanjing Heyan Road Yangtze River Tunnel, are presented as well. The development trend of China′s underwater shield tunnels, including from single soft soil formation to complex soil formation, from large diameter to super large diameter, from medium water pressure to high and ultra high water pressure, from ordinary to special and unfavorable geological conditions, from seismic regions with moderate intensity to those with high intensity, and from single construction method to combination of multiple methods, are analyzed. It is pointed out that the technical fields still require further study and innovation, and the areas still require further enhancement and innovation, such as the norms, codes, designs, constructions, equipment, materials and management.     

Design Method and Application of Rock and Support System for Super large Span Tunnel（超大跨度隧道围岩支护体系构件化设计方法及其应用研究）

In order to guarantee the stability of surrounding rock and support structure of super large span tunnel and realize quantification of support structure design, the optimal excavation contour line shape is obtained based on study of influence of initial ground stress on bearing arch of surrounding rock; a new quantitative design method, in which the surrounding rock is regarded as an arch structure, bolts, cables, shotcrete and lining are designed to satisfy the intensity, rigidity and stability of the arch structure, is presented to design the support structure system. The method has been successfully applied to super large span tunnel of Badaling Great Wall Station on Beijing Zhangjiajie High speed Railway; and the applicable results show that the maximum accumulative settlement of crown top of large span section is only 17.3 mm, and the relative subsidence of crown top is only 0.09%, which can meet safety requirements.     

Prospect of Infrastructure Construction under "Belt and Road" Initiative（“一带一路”的基础设施建设前景）

The process of how the "Belt and Road" Initiative was brought up is studied and the major opportunities that the "Belt and Road" Intiative brings to China are described in this paper. The "Belt and Road" Intiative is very prospective. The important role of the infrastructure construction in the "Belt and Road" Intiative is shown. Two examples of the infrastructure construction under the "Belt and Road" strategy, i.e., China Nepal India Trans Himalaya Corridor and Kra Isthmus Canal in Thailand, are introduced. Finally, the challenges that China will face in the infrastructure construction under the "Belt and Road" Intiative and the rational countermeasures are described.     

Innovation and Future Application of Mechanized and Intelligentized Construction Technology for High speed Railway Tunnels: A CaseStudy of Hubei Section on Zhengzhou Wanzhou High speed Railway（高速铁路隧道机械化修建技术创新与智能化建造展望——以郑万高速铁路湖北段为例）

To ensure the safe, rapid and high quality construction of Zhengzhou Wanzhou High speed Railway, a series of exploration and innovation of construction technology, structural design and information management under the condition of large scale mechanization is used in the whole construction process. The technology includes: （1）A set of advanced geological prediction, advanced pre reinforcement technology of excavation face, mechanized construction technology of primary support, wide waterproof board trolley operation technology and intelligentized full face lining trolley of large scale mechanized construction technology are formed. （2）A classification method of surrounding rock stability is established based on the mechanized construction technology, and the design parameters of the tunnel support structure are optimized under the guidance of New Austria Tunneling Method. （3）To realize informatized management of tunnel construction, the tunnel construction management system, construction information record system, construction safety management system, quality management system of concrete mixing station and quality credit evaluation system are established. Finally, on the basis of mechanized and informatized construction, exploration and outlook of the tunnel intelligentized construction technology are given from the aspects of the dynamic intelligentized design system of tunnel support system, the intelligentized robot construction technology of tunnel support system and the intelligentized monitoring system of tunnel structure, to promote China′s tunnel construction technology.     

Questions and Answers

我最近想给我的爱车换轮胎．但听朋友说市面上有很多翻新轮胎，一定要认真识别，谨防上当．请问如何才能鉴别翻新轮胎和新轮胎呢？     

Questions and Answers

Q：我想给自已的爱车加装防盗器，但面对琳琅满目的品牌，请问应该如何选购？     

Questions and Answers

广州 刘小川 Q：夏天快到了，我想给自己的爱车配备一个车载灭火器，以防万一，请问使用车载灭火器应该注意些什么？     

Uestions and Answers

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Shenzhen and Automobiles

With total area of 2020 km~2 peopled by 3.35 million, Shenzhen is situated in the south of Guangdong Province of China, bordering on New Territories of Hong Kong in the south, overlooking the Daya Bay in the east, and meeting the Pearl River Estuary in the west. Designated as the first Chinese special economic zone     

Questions and Answers

我的车已经开了1年多了，淡知道刹车片是不是已经磨坏了，请向自己怎样才能判断刹车片的磨损情况。     

Present Situation and Forecast of Chinese Rubber and Tire Products

1 Status Quo of China Auto Rubber and Tire Industries 1.1 Rubber The application of special rubber with high performance in the auto industry has seen an increasing tendency in recent years. Along with the progress of the auto industry, auto engine is towards great power, but miniaturization, ambient temperature of engine is getting higher, requirements of emission control     

Key Technology of Overlength Pressure Tunnel in Water Supply Project in Central City of Jilin Province（吉林引松工程超长有压隧洞关键技术）

Water Supply Project in the Central City of Jilin Province is a large scale project which involves complex geological condition and high technical difficulties. In order to maximize the water delivery, the overlength pressure hydraulic tunnel is introduced. Based on detailed geological survey and other reliable technical references, this project can be treated as a demonstration in terms of how to lay large diameter TBM through a karst area with limestone. The in situ test is introduced to test the non bonded pre stress circumferential anchor tunnel structure and culvert structure when the water transmission engineering line crosses the shallow buried valley section. The Class Ⅰ and Class Ⅱ granite tunnels excavated by TBM is not aligned with saving project investment and speeding up construction progress. The BQ method is introduced to analyze the rock quality classification of long tunnels. There are not many domestic engineering examples of the above mentioned key technologies, and there are no mature theories and experiences to refer to. Based on theoretical research, numerical calculations, model tests, and productive in situ tests, those key technical problems of ultra long and pressurized tunnels are solved. This project has a great theoretical and engineering value.