Experimental Research on Fatigue Behavior of Reinforced Concrete Reams Strengthened with HPFL under Overloading Conditions

In　order　to　study　the　fatigue　behavior　of　RC　beams　strengthened　with　High　Performance　Ferrocement　Laminates　(HPFL)　under　overloading　conditions,static　and　fatigue　experiments　were　conducted　on　two　control　beams　and　nine　strengthened　beams　The　failure　mode,fatigue　life,deflection　and　material　strain　under　overloading　conditions　were　analyzed　The　result　shows　that　(1)　fatigue　failure　of　the　beams　subjected　to　overload　starts　with　steel　rupture　at　the　bottom　and　the　fatigue　life　is　only　between　327　000　and　668　000　while　fatigue　 life　of　strengthened　beams　is　greater　than　two　million　times　in　case　of　not　overload ing;　(2)　compared　with　the　control　specimen,the　fatigue　life　of　strengthened　beams　is　obvio usly　extended　and　increased　with　the　increase　of　steel　mesh　consumption;　(3)　after　the　same　number　of　cycles,the　deflections,the　strains　of　concrete　and　steels　of　four　strengthened　beams　are　lower　than　those　of　the　control　specimen　Debonding　at　the　interface　of　HPFL　and　concrete　is　not　observed　because　of　shear　pins　planted　at　the　end　of　the　beams     

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     

Experimental Study on Damage Assessment of Concrete T-beam Bridges

The　effect　of　damaged　transverse　connection　of　diaphragm　beams　on　the　bearing　capacity　of　prefabricated　concrete　T?beam　bridges　was　studied　through　model　experiment　and　finite　element　analysis　On　the　basis　of　standard　drawing　of　16　m　T?beam　bridge,a　refabricated　concrete　T?beam　bridge　model　on　the　scale　of　1　to　4　was　designed　by　using　of　welding　steel　plate　The　impacts　of　different　condition　on　transverse　load　distribution　were　discussed　The　result　shows　that　(1)　flange　connection　has　little　impact　on　the　transverse　load　distribution　when　the　diaphragm　beams　are　connected　reliably;　(2)　the　damage　of　transverse　connections　has　much　influence　on　the　transverse　load　distribution　of　adjacent　girders　but　it　has　little　effect　on　the　girders　apart　from　them;　(3)　if　a　certain　transverse　connection　is　damaged　entirely　except　for　that　of　the　end　diaphragm　beams,the　load　distribution　would　not　degenerate　to　the　conditions　determined　by　the　flange　connection　because　of　the　advantageous　effects　of　the　other　diaphragm　beams;　(4)　only　when　the　bilateral　diaphragms　of　one　beam　are　damaged　at　the　same　time,the　lateral　load　distribution　will　degenerate　to　the　conditions　determined　by　the　flange　connection     

Application of High-elastic Modified Asphalt in Steel Bridge Pavement

To　cope　with　the　fatigue　cracking　occurred　to　the　asphalt　mixture　on　steel　deck　avement,it　is　put　forward　that　the　fatigue　life　of　asphalt　mixture　can　be　improved　by　reducing　the　ailure　energy　of　each　hysteresis　loop　of　asphalt　mixture　according　to　the　cumulative　dissipated　energy　and　hysteresis　loop　theory　in　the　principle　of　viscoelasticity　for　asphalt　mixture　Based　on　this　principle,a　kind　of　modified　asphalt　with　high　elasticity　was　developed,and　its　high　and　low　temperature　performances　and　fatigue　performances　were　also　tested　The　result　shows　that　(1)　low　temperature　deformability　of　the　high?elastic　modified　asphalt　mixture　has　remarkably　improved　and　low　temperature　bending　strain　of　girder　at　-10　℃　is　above　10　000　με;　(2)　the　fatigue　life　of　modified　asphalt　mixture　with　high　elasticity　has　greatly　improved　by　4?point　bending　beam　test　compared　with　common　modified　asphalt　mixture　The　fatigue　life　at　1　000　με　deformability　is　about　19　million　times　which　is　about　20　times　longer　than　that　of　ordinary　asphalt　mixture     

Micromechanical Analysis on Viscoelasticity of Asphalt Mixtures

Mori-Tanaka　equivalent　inclusion　micromechanics　theory　was　employed　to　investigate　the　viscoelasticity　of　asphalt　mixture　Asphalt　mixture　was　regarded　as　composites　which　treated　coarse　aggregate　as　a　rigid　inclusion　and　the　mixture　of　fine　aggregate,filler　and　binder　as　viscoelastic　matrix　The　constitutive　relations　of　coarse　aggregate　inclusion　and　fine　aggregate-filler-binder　matrix　were　converted　into　elastic　problems　by　Laplace　transformation　Then　the　Mori-Tanaka　equivalent　inclusion　and　average　theory　were　used　to　deduce　the 　viscoelastic　performance　of　asphalt　mixture　based　on　that　of　asphalt　mortar　in 　Laplace　space　The　result　shows　that　(1)　coarse　aggregate　inclusion　can　enhance the　viscoelastic　performance　of　fine　aggregate?filler?binder　matrix　and　viscoelastic　constitutive　relation　of　asphalt　mixtures　can　be　expressed　as　the　product　of　an　enhancement　coefficient　of　coarse　aggregate　and　the　viscoelastic　constitutive　relation　of　fine　aggregate?filler?binder　matrix;　(2)　the　viscoelasticity　of　the　complex　asphalt　mixture　can　be　predicted　from　the　viscoelasticity　of　the　homogeneous　fine　aggregate?filler?binder　matrix　by　using　the　nhancement　coefficient;　(3)　the　enhancement　coefficient　is　higher　than　10　and　it　rises　with　increasing　of　coarse　aggregates'　volumetric　fraction　or　Poisson's　ratio　of　fine　aggregate-filler-binder　matrix　but　the　effect　of　the　former　is　more　important　than　that　of　the　latter     

Impacts on Asphalt Mixture's High Temperature Performance with PR Series Additives Added

Impacts　on　asphalt　mixture's　high　temperature　performance　with　PR　series　additives　added　by　means　of　rutting　test　and　Repeated　Shear　Test　(Constant　Height)　(RSCH)　were　investigated　The　analytic　results　of　the　two　tests　show　that　(1)　rutting　test　is　not　suitable　for　the　high　temperature　performance　evaluation　of　asphalt　mixture　with　PR　series　additives　added　for　the　reason　of　the　conflict　between　dynamic　stability　and　rut　depth;　(2)　the　results　of　RSCH,such　as　K1,K2,N　and　γ,show　very　well　consistency　which　is　suitable　 for　the　high　temperature　performance　evaluation　of　asphalt　mixture　with　PR　series　additives 　added　The　results　of　RSCH　show　that　asphalt　mixture　with　PR　PLAST　S　(PRS) 　added　has　the　best　performance,the　PR　FLEX　MODULE　(PRM)　one　is　the　next　and　t he　original　one　is　the　worst　for　the　high　temperature　anti?shear　performance     

Evaluation of Low?temperature Performance of Porous Asphalt Mixture

To　analyze　influencing　factors　and　evaluation　method　of　low-temperature　performance　of　porous　asphalt　mixture,first,three　kinds　of　modified　binder　were　chosen　as　original,thin　film　aging　and　pressure　aging　samples　for　customary　index　test　and　bending　beam　rheometer　(BBR)　test　at　-12　℃　to　evaluate　low-temperature　performance　of　these　modified　binders　Then,evaluation　of　the　low-temperature　anti?cracking　performance　of　different　kinds　of　porous　asphalt　mixture　was　made　by　thermal　stress　restrained　sample　test　(TSRST)　At　the　sam e　time,the　result　of　abovementioned　TSRST　were　compared　with　the　TSRST　result　of 　samples　of　the　porous　asphalt　mixtures　after　long?term　aging　to　evaluate　the　influence　of　 aging　on　low-temperature　performance　of　porous　asphalt　mixtures　The　results　show　that　(1)　TSRST　result　of　porous　asphalt　mixtures　coincides　with　creep　stiffnesses　of　BBR　test　of　modified　binders;　(2)　the　fracture　temperatures　of　the　porous　asphalt　mixtures　increase　and　their　fracture　stresses　decrease　after　aging;　(3)　the　fracture　stresses　of　porous　asphalt　mixtures　are　just　one-third　of　those　of　dense?gradation　asphalt　mixtures　while　the　fracture　temperatures　almost　the　same,which　indicates　that　their　low?temperature　performances　are　almost　the　same     

Research on Adaptability of Semi?rigid Material as Base Course for Long-life Asphalt Pavement

In　the　light　of　semi?rigid　material　as　base　course　for　perpetual　asphalt　pavement,the　bearing　capacity　and　fatigue　life　of　asphalt　pavement　with　semi-rigid　base　cause　and　different　asphalt　layer's　thickness　were　computed　with　BISAR30　after　chosen　typical　pavement　The　impact　of　thickened　layer　on　the　stress　of　the　semi?rigid　base,the　dry　shrinkage　and　temperature　shrinkages　of　the　material　were　analyzed,and　its　adaptability　as　base　for　perpetual　pavement　was　studied　The　result　shows　that　(1)　under　the　same　load,with　thickening　of　the　asphalt　layer,the　compressive　stress　on　the　top　and　the　tensile　stress　at　the　bottom　of　the　semi?rigid　base　decrease　obviously　and　the　fatigue　life　of 　the　base　increases　substantially;　(2)the　impact　of　temperature　and　humidity　on　the 　semi-rigid　base　is　remarkably　weakened,which　leads　to　the　fractures,erosion　and　reflecting　cracks　of　the　semi?rigid　base　to　be　controlled　effectively     

Analysis of Performance of High Liquid-limit-soil Foundation Reinforced by Geogrids

According　to　the　features　of　high?liquid?limit　foundation　in　southwest　mountainous　area　and　the　characteristics　of　geogrid　reinforced　cushion,geogrid　reinforced　cushion　was　used　to　reinforce　high?liquid　foundation　By　using　the　elastic?plastic　finite　element　analysis method,the　mechanisms　of　the　geogrid　reinforced　cushion　were　studied　The　results　show　that　geogrid　reinforced　cushion　can　greatly　reduce　loading　and　deformation　and　improve　the　high?liquid　foundation　stability　In　addition,the　effect　of　factors　such　as　location,lay ers,stiffness,etc　of　geogrids　on　reinforcement　and　the　regularity　were　discussed　Compari son　of　centrifugal　model　test　result　with　numerical　calculation　result　indicates　that　the　error　is　negligible　between　them,which　shows　that　(1)　constitutive　relationship,calculation　model　and　calculation　parameters　are　reasonable;　(2)　numerical　simulation　reflects　deformation　behavior　of　high?liquid　foundation　improvement　effectively　and　the　results　of　numerical　analysis　are　re liable     

Coupled Numerical Analysis of Anti?crack Mechanism of Large Stone Asphalt Mixture

Stresses　of　pavement　with　flexible　base　of　LSAM-30,ATPB-30　and　AC-30I　at　the　most　adverse　point　under　the　function　of　traffic　load　and　temperature　load　as　well　as　the　coupling　of　them　were　calculated　and　compared　by finite　element　method.　The　result　indicates　that　flexible　bases　of　LSAM?30　and　ATPB?30　are　more　effective　in　the　prevention　of　reflection　crack　Because　of　the　great　volume　of　coarse　aggregate　and　large　maximum　nominal　particle?size,the　LSAM-30　thermal　conductivity　is　greater,and　the　temperature　shrinking　coefficient　is　lower　as　well　as　the　modulus　of　resilience,which　could　reduce　the　emperature　gradient　among　the　structure　layers　effectively　and　then　minish　the　thermal　stress　At　the 　same　time,the　adequate　flexibility　performance　of　the　LSAM　may　also　absorb　strain　energy　at　the　crack　of　the　semi?rigid　subbase　sufficiently　As a　result,itpresented　preferable　reflection　crack　resistance　A　case　study　was　conducted　to do　comparative　analysis　of　anti?cracking　performance　of　LSAM-30,ATPB-30　and　AC-30I　flexible　bases　A　long?term　follow?up　observation　of　test　roads　with　the　three　bases　shows　that　the　pavement　with　LSMA　base　is　in　good　condition　and　no　sign　of　crack　found　while　pavements　with　ATPB?30　and　AC?30I　flexible　bases　have　varying　degrees　of　crack　LSMA　flexible　base　has　an　obvious　performance　of　anti-crack     

Research on Heat Transfer Model of Asphalt Pavements Subjected to Microwave Heating Recycling

In　order　to　assess　temperature　field　in　microwave　heating　for　recycling　asphalt　pavements,a　2D　mathematic　heat　transfer　model　was　developed　based　on　Fourier　heat　transfer　theory　The　microwave　internal　heat?generation　was　researched　by　using　surface　field　of　pyramidal　horn　replacing　approximate　radiation　field　In　addition,the　boundary　conditions　were　built　and　normalization　processing　was　implemented　The　control　volume　based　finite　differential　method　(CV-BDM)　was　used　to　establish　the　implicit　discrete　scheme　of　the　conservation equations,and　the　numerical　value　simulation　was　employed　By　continuous　or　intermittent　 radiation　heating　technique,a　microwave　heating　experimental　system　at　2　145　GHz　was　carried　out　to　investigate　temperature　variation　characteristics　of　asphalt　pavements　along　with　heating　time　The　result　shows　that　(1)　the　increase　of　temperature　of　asphalt　mixture　during　microwave　heating　is　obviously　nonlinear,the　temperature　rises　slowly　in　the　initial　stage　of　the　heating　but　increases　rapidly　in　the　late　heating　period;　(2)　the　temperature　distribution　is　non-uniform　that　the　temperature　in　central　area　of　the　surface　is　higher　while　it　is　lower　on　edge;　(3)　the　uniformity　of　temperature　within　asphalt　mixtures　can　be　improved　by　using　intermittent　heating　technique,and　the　heating　time　must　be　reasonable　The　simulation　results　are　in　preferable　agreement　with　the　experiment     

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.     

Reflections on Construction of Bohai Bay Crossing Corridor（对兴建渤海海峡跨海通道有关问题的思考）

The author discusses the necessity and urgency of constructing the Bohai Bay Crossing Corridor from the following aspects such as the increasing traffic volume, the convenience of the transportation after the corridor is constructed, and the regional benefit brought by the corridor. As for the timing of the construction of the sea crossing corridor, the author thinks that as long as the national economic situation permits and relevant conditions are basically available, the preliminary work should be carried out as soon as possible so as to promote the early commencement of the construction. Regarding the proposal of building another coastal national highway/high speed railway along the Bohai Bay coast, the author puts forward his viewpoints. In the aspect of construction risks, the author thinks that the geological risks in the construction of the Bohai Bay Crossing Corridor are very difficult to be dealt with; therefore, strict and detailed risk assessment should be carried out, and effective safety measures should be taken to mitigate the risks. The author also briefly describes the technological advantages of the tunnel proposal selected for the Bohai Bay Crossing Corridor, and briefly analyzes some key technological issues in the tunnel construction. The author describes the construction scheme and construction period estimation for the sea crossing corridor in details. The author makes the following proposal are given: (1)the hard rock tunnel boring machine (TBM) assisted by the drilling and blasting method should be used for the construction of the long sea crossing tunnel of Bohai Bay Crossing Corridor; (2) a parallel service tunnel shall be arranged between the twin main tunnel tubes; (3) in Proposal 2, the diameters of the twin main tunnel tubes and the service tunnel should be 8.0 m and 55 m, respectively. The proposal has two optional solutions: Solution 1: The service tunnel ( 55 m) located between the main tunnel tubes will be constructed first; for the main tunnel tubes, the disassembled TBMs ( 8 m) and the backup gantries are assembled for tunneling after arriving at the main tunnel tubes through the service tunnel and the cross passage; Solution 2 (alternative): Tunneling with  55 m TBM is carried out; the  55 m TBM will be dismantled to pass through the cross passage, and then be re assembled after arriving at the main tunnel; the start section (180 m) of main tunnel tube will be formed by  55 m TBM before it is enlarged to  8 m by drilling and blasting method; or the cross passage is enlarged to a large curved space to allow the 5.5 m TBM passing throught without disassembly. Comparison and contrast will be made and the preferred solution will be adopted. According to the rough estimation on the construction period of the 125 km long sea crossing tunnel, the total construction period of "completed tunnel" will be about 19 years (including 5 years of detailed offshore investigation) in Solution 1.     

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 Construction Technologies for Overlapping Twisted Shield bored Tunnels in Weak Water rich Strata(富水软弱地层中麻花型盾构隧道群施工关键技术)

The project under study is an overlapping twisted shield bored tunnels in weak water rich strata. The purpose of the study is to solve the key technological problems in the construction of the project. The optimal construction sequence of the overlapping twisted shield tunnels is determined according to the engineering geological conditions, the surrounding working environment, and theoretical analysis on the spatial relationship of the four tunnels, and verification control are carried out via monitoring means. The tunnel construction is properly timed, smart self propelled movable support jumbo is adopted, and grouting reinforcement technology is used to ensure the construction safety of the overlapping twisted shield bored tunnels. The grouting pre reinforcement technology and the clay shock technology are adopted to ensure the safety of the surrounding buildings. The technologies for the construction of the overlapping twisted shield bored tunnels described in this paper is of great significance for the construction of similar overlapping tunnels with high shield launching/receiving risks and crossing under important structures with small clearance.     

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.     

Research on Erection Methods of Steel Stiffening Truss Girder for Baling River Bridge

Four　methods　of　erecting　steel　stiffening　truss　girder　of　suspension　bridge,including　the　deck　lifting　gantry　crane　method,the　cable-mounted　crane　method,the　cantilever　erection　method　with　derrick　crane　and　the　incremental　launching　method,were　studied　Based　on construction　conditions　of　the　bridge,according　to　the　optimal　combination　of　various　factors　such　as　construction　safety,quality,period,environmental　protection　and　economic　performance,etc,the cantilever　erection　method　with　derrick　crane　was　recommended　for　the bridge.　On　this　basis,three　categories　of　connection　in　cantilever　erection　methods,including　the　all　hinged　method,the　successive　fully　splicing　method　and　the　successive　splicing　with　temporary　erection　hinge　method,were　studied　The　successive　splicing　with　temporary　erection　hinge　method　was　recommended　in　the　bridge　with　consideration　of　the　requirements　of　construction　safety,quality　and　time　limit　In　addition,the　traction　method　of　hangers　at　the　top　end　during　cantilever　erection　was　studied　Finally,the　erection　method　of　three　key　 stages,including　the　first　segment　near　the　pylon,the　standard　segment,as　well　as　the　closure　segment　of　steel　stiffening　truss　girde,r　was　studied.　The　cantilever　erection　method　with　derrick　crane　provides　a　new　way　for　design　and　construction　of　long-span　suspension　bridge　with　steel　stiffening　truss　girder　in　the　western　area　of　China     

杭州狭长软土基坑支护侧移规律与解析预测方法研究

In order to reduce the influence of deep narrow foundation pit construction on adjacent properties in urban area in Hangzhou, the characteristics of the support wall lateral deflection are analyzed and the corresponding analytical prediction method is proposed. The support wall lateral deflections of the deep narrow foundation pits at Wenyi West Road, Qingchun Station, Qiutao Station, Xingtang Station and Qingnian Station in Hangzhou soft clay are monitored and compared with those of deep foundation pits in Zhejiang and deep narrow foundation pits in Shanghai, Taipei and Singapore. The results show that the maximum support wall lateral deflection of the foundation pit on Wenyi West Road, 0.20%He ~0.25%He, where He is the maximum excavation depth, is close to that in Shanghai(0.15%He~0.41% He), but is smaller than those in Zhejiang, Taipei and Singapore(0.27% He~0.62% He); which is related to the high tangential modulus of Hangzhou soil and small width of the foundation pit. The support wall lateral deflection of the narrow deep foundation pits in Hangzhou can be precisely predicted based on the representative stress strain relationship at site and the modified mobilisable strength design (MMSD) method.     

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.     

Construction Technologies for Tunnels in Special and  Complicated Geology of Lanzhou Chongqing Railway（兰渝铁路特殊复杂地质隧道修建技术）

Lanzhou Chongqing Railway is located in the uplift margin of the Tibetan Plateau, where the geological environment is very complicated and special. Based on numerical analysis and field tests, the physical and mechanical properties, micro structure, and complicated water related stability of the Tertiary sandstone are studied. A comprehensive dewatering system integrating deep surface wells and vacuum light well points in tunnel is used and the construction technique featured with advance reinforcement by horizontal jet grouting for the full face of aquiferous silty fine sand tunnels is invented to solve the problem of the Tertiary quick sand. In addition, the classification method for deformation potentiality in design and dynamic adjustment in construction of tunnels in high geostress soft rock is established, the deformation control technology combining active stress release and passive control according to the deformation mechanism is developed, an automatic real time monitoring system for operation is invented, and a complete technological system of design, construction, and operation management of soft rock tunnels is built. Moreover, the TBM equipment parameter design principles are put forward, the parallel lining and multi stage belt conveyor mucking system is researched, the phased ventilation technology is invented and thus the problem of safe and fast long distance construction by large diameter TBMs is solved. The technological achievements have filled in gaps and facilitated development of the tunnel construction technology.