Study of Engineering Geological Conditions and Railway Tunnel Scheme across Qiongzhou Strait（琼州海峡工程地质条件及铁路隧道方案研究）

The cross sea channel for the Qiongzhou Strait not only provides a solution for transportation, but also plays an important role in the political and economic development of the region. In addition, the project has an extensive impact on many fields, such as energy, national defense, science and technology, opening up and reform, comprehensive utilization and so on. It is a significant project to enhance China′s comprehensive national strength, defend the country′s territorial integrity and promote regional economic development. The geological conditions across the Qiongzhou Strait are complex. A large amount of existing engineering geological information and hydrogeological data are collected, based on which the seismic impact on subsea tunnels and the main geological conditions including tectonic structures are analyzed. Different options crossing the Qiongzhou Strait have been considered and compared in terms of engineering geology, environmental condition, as well as the construction feasibility. The analystical results indicate that a subsea tunnel has more advantages over a bridge. Because more complicated technical difficulties have to be solved for a highway tunnel which would potentially increase construction and operation costs, a railway tunnel scheme is recommended. Vehicles can be carried by trains through the Qiongzhou Strait railway tunnel. Based on the seabed topography and geological conditions, four preliminary railway tunnel routes are proposed. After a comprehensive comparative analysis, the railway tunnel route Ⅱ is identified to be superior to other alternatives and should be the basis for determining the final tunnel layout. The proposed tunnel cross section includes two railway tunnels and one service tunnel. All the three tunnels have the same structural form and dimension and will be constructed by shield.     

Development and Thinking of Tunnels and Underground Engineering in China in Recent 2 Years （From 2017 to 2018）（近2年我国隧道及地下工程发展与思考（2017—2018年））

The author gives an overview of the development of tunnels and underground engineering in China in the past two years, including railway tunnel, high speed railway tunnel, highway tunnel, metro tunnel, hydraulic tunnel and utility tunnel, and introduces some key and representative railway, highway and municipal tunnels projects, i.e. Muzhailing Tunnel on Lanzhou Chongqing Railway, Dangjinshan Tunnel on Dunhuang Golmud Railway, immersed tunnel of Hong Kong Zhuhai Macao Bridge, China Laos Railway Tunnel, Gaoligongshan Tunnel on Dali Ruili Railway, Yuelongmen Tunnel on Chengdu Lanzhou Railway, Tianshan Shengli Tunnel on Urumchi Yuli County High speed Railway, Shenzhen Zhongshan Passage, Su′ai Tunnel in Shantou, Ka Shuang Tunnel of Ertix River Water Diversion Project, Qianhai underground integrated hub in Shenzhen and underground integrated structure of Optics Valley Square in Wuhan. The author also introduces the development and progress in the fields of engineering investigation technology, BIM technology, mechanized and intelligent tunnel construction technology, shield/TBM manufacturing and remanufacturing technology, offshore immersed tube tunnel construction technology, non circular shield tunnel construction technology, tunnel big data platform construction technology, etc. According to the operation of series national strategies and planning such as Sichuan Tibet Railway, coordinated development of Beijing, Tianjin and Hebei, the Yangtze Economic belt, and the Guangdong Hong Kong Macao Greater Bay Area, following technical demands are proposed, namely, sea crossing tunnels, construction of complex and long distance tunnels, environmental protection technology for tunnel construction in ecologically vulnerable areas, development of large scale urban underground complexes, research and development of new materials in alpine environment, intelligent diagnosis of tunnel diseases and rapid repairs, intelligent disaster prevention of ultra long complicated tunnels and underground engineering, etc. Some thoughts and suggestions are put forward in two aspects of engineering construction management mode and mechanization supporting in combination with the development status of the industry.     

Construction Behavior of Double Down?side Drifts in a Weak Tunnel with Shallow Cover

Confronted　with　accidents　in　a　shallow?buried　weak　tunnel　using　the　bench　excavation　method,such　as　great　subsidence　and　cracks　in　the　ground　surface　as　well　as　those　in　the　preliminary　support,a　double　downside　drifts　construction　method　was　presented　The　drifts　were　used　to　detect　geological　conditions　and　reinforce　the　lower　parts　of　the　tunnel　Its　construction　procedures　and　load　transiting　mechanism　were　then　described　Its　Construction　behavior　was　also　studied　by　numerical　simulation　using　software　MIDAS　The　results　show　that　(1)　double-side　drifts　can　improve　tunnel　load,the　key　construction　step　is　arch　ring　excavation　and　core　soil　is　good　to　keep　tunnel　steady;　(2)　weak　parts　mainly　l ocate　at　wall　foot　of　drifts,wall　foot　and　crown　foot　of　tunnel,and　the　connections;　(3)　reinforcement　of　soil　under　the　drifts　has　no　apparent　effect　on　improving　rock　deformation　and　support　load　Advice　on　construction　was　proposed　that　main　parts　to　be　reinforced　are　drifts　(its　foot　depth,connection　parts　with　tunnel,and　its　corners)　and　core　soil　should　be　kept　if　rock　is　unsteady　and　needs　reinforcing     

Key Technology of Sea crossing Interval Tunnel in Complex  Environment Design of Xiamen Rail Transit Line 3（厦门轨道交通3号线复杂环境过海区间隧道设计关键技术）

A sea crossing tunnel is generally large in scale, having a complex site environment, and lack of engineering experience. The success of the project is directly related to the design plan. At present, no metro sea crossing tunnel havd been built in mainland, and the design standard and technology of the sea crossing tunnel are not studied throughly. The key technology of long and large sea crossing metro tunnel design, including construction method selection, cross section design, waterproofing and drainage system design, response to complex environment in sea area, durability design, ventilation and evacuation are analyzd with methods of geological analysis, engineering analogy and comprehensive comparison based on the sea crossing tunnel of Xiamen Rail Transit Line 3. A combination of shield and mining methods is proposed for the geological conditions of different sections. The drainage system of the mining section can be maintained by applying advanced grouting to control displacement. The complex geology of the sea area is considered in the targeted design, including a deep weathering trough, a water rich sand layer, a hard rock and uneven stratum, and the development of solitary rocks. The durability design of the tunnel structure and the limit of the bearing capacity are treated equally to consider safety reserve. The tunnel adopts sectioned longitudinal ventilation and smoke extraction mode, and contains ventilation shafts and civil smoke extraction air shafts on shore to prevent disasters. The conclusions can provide technical support for tunnel scheme decision and reference for similar projects.     

General Design of Shenzhen Zhongshan River crossing Link Project（深圳至中山跨江通道工程总体设计）

Shenzhen Zhongshan River crossing Link is the first super integrated project in the world that consists of four different types of structures, i.e. ultra long and wide immersed tunnels, super large span sea crossing bridges, deep water artificial islands and undersea interchanges. The river crossing is designed for two way and 8 lane as per highway technical standards. Based on project characteristics and its technical difficulties, engineering solutions and the associated technology innovations have been listed as follows: (1) Proposed a design concept of standardization, industrialization, intelligence and project integration, and completed the study of overall design of Shenzhen Zhongshan River Crossing Link. An immersed tunnel with a combined steel shell and concrete composite structure is designed and the width of tunnel elements is from 46 to 55.5 m; Lingdingyang Bridge has been designed as a suspension bridge with a 1 666 m main span and two 270 m high main bridge towers. For West Island, a temporary enclosure caisson structure made of ultra large steel cylinders with a diameter of 28 m is designed to achieve a rapid artificial island formation. (2) Summarized the design and construction solutions related to combined steel shell and concrete structural immersed tunnel, the mix design, batching and concrete casting methods of high strength self compacting fluidized concrete, concrete quality check and inspection, design and construction of deep cement mixed (DCM) pile foundation for immersed tunnels, design and construction of large scale undersea dimensional transport interchange, flutter and wind stability design for super large span suspension bridge with monobox girders, and key techniques related to design and construction of offshore anchorage in deep sea. Furthermore, an equipment is developed and innovated for not only transport, also for installation of immersed tunnel elements to ensure the implementation of the project in an effective and economical way.     

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.     

Challenges and Countermeasures in Construction of  Gaoligongshan Tunnel of Dali Ruili Railway（大瑞铁路高黎贡山隧道施工挑战与对策）

In order to resolve the challenges encountered in the construction of Gaoligongshan Tunnel such as soft rock deformation of inclined shafts, water drainage and protection of vertical shafts, TBM jam in crossing areas with adverse geology, solutions and key construction techniques are developed through theoretical analysis, field test, scheme optimization and staged review and summary. The performance results of field practice show that: (1)the goal of no damages and no replacement of the primary support can be achieved by adopting the comprehensive deformation prevention technique of "ring support early formation and quick closure", setting of proper excavation line curvature, and reinforcing of support; (2)the risk of vertical shaft flooding during construction in water rich weak granite can be greatly reduced by adopting the water control principle of "exploration for any excavation, plugging as the main method, and supplemented with drainage method" and the key pre grouting technique of S shaped deep boreholes; (3)the open type TBM can quickly and safely pass through the unfavorable mylonitic granite stratum by adopting the small pilot tunnel construction method, thus the fast and high efficiency construction performance of TBM can be fully utilized.     

Great Revolution in Maritime Transportation: Discussion on Preliminary Work and Operation Plan of Bridge/Tunnel Projects for Vacuum HTS Maglev Train at High Speed（畅想海上交通运输建设的伟大革命——真空高温超导磁浮高速列车桥隧工程前期工作与运行方案探讨）

The improvement in the operation speed of the transportation project means the progress and development of the construction technologies in transportation projects. In this paper, the following factors restricting the further improving of the speed of high speed railway are analyzed: as the operation speed increases, the trains in the dense atmosphere are subject to the wind induced resistance and various resistances caused by the friction between the wheels and the rails and by the irregularity of tracks, and the noise will also increase with a high power. Therefore, the economy and safety issues involved in the operation have become the main factors restricting the further improving of the speed of high speed railway. A scheme of vacuum pipelines of underwater vacuum tunnel and/or subwater bridge is proposed in this paper: the pipelines and cars are sealed and vacuated to form the quasi vacuum. The transportation system of the vacuum maglev train at ultrahigh speed with the HTS maglev technology can achieve the operation speed more than 4 times that of the existing HSR train (about 1 200 km/h). Key technologies for constructing the vacuum maglev tunnels/subwater bridges in respect of construction plans, vacuating and sealing, as well as maglev trains are introduced in this paper. The subjects to be further studied on the vacuum HTS maglev tunnels (pipelines) are analyzed from the aspects of technology, management, construction costs, operation expenses, candidate project, airtight materials for cars and evacuation in case of emergencies. It is recommended that "cross sea maglev train in vacuum tunnel" should be developed in the eco tourism project between the coastal cities and their neighboring islands and a series of necessary technical tests should be conducted during the trial operation, so as to obtain related experience. Based on the experience and lessons learned, the transportation system at ultrahigh speed may be implemented for strait crossing projects in China. Finally, a brief introduction to the research on HSR trains at ultrahigh speed in countries such as China, the United States and the Netherlands is presented in this paper. The development of vacuum pipeline transportation can drive the development of China′s transportation modes in a faster, safer and more energy efficient manner, facilitating the development of the fifth generation of transportation industry and its driving role in the social and economic development, and promoting the integration and progress of the economy of China or even the world at a higher speed.     

Achievements and Challenges of Tunneling Technology in China over Past 40 Years（中国隧道工程技术发展40年）

In this paper, the current situation of tunnel engineering in China is introduced, especially the achievements obtained in the field of tunnel construction since the reform and opening up over 40 years. The 34 708 km long traffic tunnel built after reform and opening up takes 96% of the total length. The challenges met and achievements obtained during the key tunnel projects construction in China are presented emphatically from the aspects of extra long tunnel, deep tunnel, large tunnel, tunnel at high altitude and tunnel in complex environment. It is pointed out that: the main technological challenges during extra long tunnel construction are the accuracy of geological investigation, rapid construction and running disaster prevention; the main challenges during deep tunnel construction are high geostress, high waterpressure and high geothermal; the large tunnel faces high design and construction challenges; the challenges during tunnel construction at high altitude are freezing thawing and hypoxia; but still, many tunnels have been built under complex environments, including karst, gas, high geostress, high waterpressure, expansive rock, etc., and many technological breakthroughs have been achieved. The development trend of tunnel projects in China is proposed from the aspects of investigation, design, construction and operation, turning the development speed into development quality. It is generally acknowledged that the tunnel engineering achievements in China over the past 40 years benefit significantly from the development of international tunnel technology. Meanwhile, the development of tunneling technology in China has also greatly contributed to the international tunnel engineering development.     

Innovation and Prospect of Key Technologies of Immersed Tunnels in China（中国沉管法隧道典型工程实例及技术创新与展望）

In this paper, the application status of foundation trench excavation and navigation channel dredging, dry dock construction, element precasting, element transport, element mooring, element immersion, joint treatment and foundation treatment of several typical immersed tunnels in China are introduced. And then the Honggu Immersed Tunnel in Nanchang and subsea tunnel of island tunnel project of Hong Kong Zhuhai Macao Bridge are taken as examples; and some innovations of key technologies, i.e. key construction technology, element transport and immersed technology, differential settlement control technology for element immersion, subsea connection technology, and subsea space development and subsea harbor construction technology, are summarized for river crossing and sea crossing immersed tunnels. Finally, the development trends of immersed tunnels are prospected based on new technologies and equipments from the aspects of prolongation of immersed tunnel, field breakthrough, urban construction promoting and traffic demand adding of cities along rivers and seas. The results can provide reference for construction and popularization of immersed tunnels.     

Comparison and Selection of Ventilation Schemes for Zhagaliang Extra long Highway Tunnel（扎尕梁特长公路隧道通风方案比选研究）

In order to select a suitable ventilation scheme for a single tube extra long highway tunnel with two way traffic, as well as to solve problems in smoke exhaust and personnel evacuation in such tunnel, 3 ventilation schemes are proposed. According to the characteristics of Zhagaliang extra long highway tunnel, the 3 ventilation schemes include confluent ventilation with exhaust shaft and longitudinal ventilation with jet fans, parallel pilot tunnel forced ventilation network, and longitudinal ventilation with jet fans and sectional smoke exhaust by inclined shaft. The ventilation schemes are compared from several aspects, i.e. civil construction cost, initial investment of mechanical and electrical equipment, electricity cost during tunnel operation, ventilation control, stability of ventilation network, applicability, management and maintenance. Finally, the most suitable ventilation scheme is selected by comparing the advantages and disadvantages of each scheme, i.e. longitudinal ventilation with jet fans and sectional smoke exhaust by inclined shaft. Under the normal operation condition of the tunnel, longitudinal ventilation with jet fans is adopted in the main tunnel, and on demand ventilation can be realized. Smoke can be exhausted by inclined shaft in case of fire, which can solve the problem of smoke exhaust only in two sections by the parallel pilot tunnel. The parallel pilot tunnel can also be used for personnel evacuation and rescue.     

Study of Collaborative Management of Intelligent Highway Tunnel（智慧公路隧道协同管理研究）

Aiming to solve the problems of collaborative management of intelligent tunnel and tunnel management under different traffic conditions, the tunnel is regarded as a part of highway, and five features of the intelligence are proposed from the definition of intelligence. In order to realize a collaborative management of intelligent highway tunnel, the spatial extent of tunnel is defined at first. Then, a collaborative management road topology based on road critical nodes is proposed; and a holographic collaborative control information system based on tunnel structure, facilities, vehicle, operation, management, and environment is established. Finally, collaborative control of people, cars, roads and environment could be realized, so as to improve the management level of the intelligent highway tunnels.     

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.     

Analysis of Adaptability of TBM in Trial Boring Stage of Super long Tunnel（超特长隧洞TBM集群试掘进阶段适应性分析）

The total length of the 2nd stage water transfer project in the northern area of Xinjiang of China is 540 km. The project consists of three tunnels, namely Xi Er (XE) Tunnel, Ka Shuang (KS) Tunnel and Shuang San (SS)〖HJ6.5mm〗 Tunnel, with lengths of 139.04 km, 283.27 km and 92.15 km respectively. All of these three tunnels have deep cover and are super long tunnels, and 95.6% of the total length of these three tunnels is constructed by TBMs. KS Tunnel is the longest water tunnel built or under construction in the world. In the paper, the trial TBM boring scheme and schedule of the water transfer project are introduced; the geological conditions revealed are statistically analyzed; and main project difficulties, i.e. durability of key equipment in long distance driving, passing through fault and fracture zones, water inrush, single head ventilation and transportation in long distance tunneling, anti slope drainage, and rock breaking efficiency and boring efficiency, are put forward. The adaptability of the TBMs used is analyzed from the aspects of adaptability to different surrounding rocks, adaptability to bad geological conditions and countermeasures, long distance ventilation and belt conveyor mucking and countermeasures, and TBM boring stability (such as equipment availability, boring time proportion, system malfunction and operation time). The following conclusions are obtained: (1) Accurate geological survey is the precondition of efficient tunneling. (2) The open type TBM can better adapt to Grade Ⅱ and Ⅲ of surrounding rocks, jointed and fractured zones and small faults; the adaptability of the TBMs used to the large scale fault fracture zones and water rich strata in this project is poor, and it needs to be improved in aspects of TBM equipment, supporting and construction technology. (3) The average availability of the TBM equipment in the trial boring stage is 89.9%, however, the malfunction rate of some ancillary equipment is high, particularly oil leakages occur to the main bearing seals; in order to achieve long distance tunneling, it is necessary to further improve the reliability and durability of the TBM equipment. (4) The average net boring efficiency in the trial boring stage is 296%, and TBM1 in Section Ⅱ of SS Tunnel achieves up to 45.2 % net boring efficiency; and highest monthly progress rate is 1 280 m, which created the highest record of the open type TBM boring in China. (5) TBM need to make great efforts to achieve 90% of the equipment system′s availability and over 40% of the tunneling efficiency.     

Construction Technology and Application of the Direct Pipe Method（直接铺管施工技术与应用）

In recent years, the Direct Pipe Construction Technology, as a new construction method and a new equipment in the international trenchless field, has gained advantages over the horizontal directional drilling (HDD) method where the construction site is limited, there is a big elevation drop between the launch and reception points, the burial depth of the pipeline is shallow, or the construction cost of the pipejacking is high. This method combines the characteristics of microtunneling and HDD. When the tunneling equipment is excavating, prefabricated pipes are laid by pipe thrusters simultaneously. The Wuding River Crossing Project of the 4 th Shaanxi Beijing Pipeline has a big elevation drop and a complex geology. The crossing project was carried out using the Direct Pipe method, which achieved a fast construction speed, simple construction process and less land occupation. The project has also achieved good economic and social benefits.     

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.     

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.     

Study on Model Experiment of Prestressed Concrete Skewed Box Girder with Transversely Segmental Construction

he　prestressed　concrete　skewed　box　girder　with　transversely　segmental　construction　was　brought　out　on　the　basis　of　the　need　in　the　engineering,both　model　experiments　and　FE　analysis　of　the　presented　construction　and　the　beam　box　with　integral　construction　were　carried　out　With　the　analysis　of　the　obtained　data　by　mathematical　statistics,comparison　of　table　and　graph,and　the　corresponding　FE　analysis,the　difference　of　mechanical　performances　of　both　constructions　was　analyzed　under　various　experimental　loading　cases　The　results show　that　(1)　the　deflection　of　the　presented　construction　is　about　53%　larger　than　that　of　the　beam　box　with　integral　construction,the　longitudinal　strain　is　135%　larger　than　that　of　the　latter,and　the　longitudinal　strain　of　the　cast　concrete　is　59％　as　large　as　that　of　the　same　area　at　the　beam　box　with　integral　construction　before　concrete　cracking;　(2)　there　exists　stress　redistribution　in　the　cross-section　of　presented　construction,which　can　restrain　the　tensional　distortion　of　the　wet?joint,and　the　value　of　the　stress　cannot　be　computed　by　the　current　FE　program     

Innovation and Practice of Hard Rock TBM in China（我国硬岩掘进机的创新与实践）

In recent years, with the help of good national policy support, the design, manufacturing and construction technology for tunnel boring machine (TBM) in China have been greatly improved; but compared with foreign relatively proven technology, there is still a certain gap for domestic technology development and engineering application. Based on the situation analysis of research and application of TBM in China and abroad, the research work for TBM design is carried out according to the complex geological conditions of Gaoligongshan Tunnel on Dali Ruili Railway as follows. (1) The prototype disc cutter rock breaking and scaled disc cutter wearing experiment are carried out to provide reference for adaptable design of TBM cutterhead and key parameter calculation. (2) The TBM design scheme is discussed from the aspects of high efficiency rock breaking of cutters and cutterhead, TBM over excavation, integrated support system, etc. (3) Two kinds of advanced geological prediction technology, i.e. HSP method and RTP method, are researched. The study results can provide reference for design and manufacture of TBM with high adaptability in complex geology and construction application in Gaoligongshan Tunnel.     

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.