Research conclusions:The structure strength and the shear strength of loess was extremely sensitive to the water． The of cohesion of shear strength was quikly reduced as moisture content increased． Slope stability depended on whether the seepage belt was formed in the slope surface which strength was promptly decreased as water content increasing． The needle pore determined the loess up － right． The stable natural slope of loess and caves were the scientific choices．

Research conclusions:The PHC body quality stability，penetration capacity，single pile bearing capacity and strength are high，price is lower，construction speed is fast，and pile’s body is convenient detected，which increase the engineering quality and economic benefit． So that supplies a kind of safe and stable foundation reinforced means in the inter － city none － ballast track super railway embankment foundation settlement key technique．

Research conclusions:The safety，energy－saving，construction investment，urban planning，environmental impact，topography and geology conditions，the comprehensive research is done on the alignment of the Zhangjiakou－Tangshan Railway to improve the construction scheme for obtaining the rationality in economics and technology， small environmental impact and best comprehensive benefits． The principle and method presented for the comprehensive alignment can offer the reference to the alignment design of haevy － haul railway and other railways．

Research conclusions:The results show that the soil in the place ahead rise to the maximum volume of 4.287 mm under the effect of excavation pressure of the working face，and the soils above and at back of the shield settle with the maximum settlement volume of 6.651 mm under joint effects of the soil loss，stress release and gap of shield end caused by the tunneling．Furthermore，the vertical，transverse and longitudinal displacements of bridge abutment while tunneling can not be ignored． The impact of the base displacement of the abutment should be considered while analyzing the bridge superstructure．

Research conclusions:When verifying the load bearing capacity of old bridge，the procedures of overall inspection，detailed detection，calculation of load bearing capacity of the beam and the verification of the load bearing capacity of the bridge should be followed． It means that，firstly，the reduction coefficient is defined according to the overall working situation and the defect situation of the bridge，then the load bearing capacity of the beams with most serious defects or bearing maximum load is calculated，and finally，the load bearing capacity of the bridge is verified according to calculation result． The verification of the load bearing capacity of the bridge presented in this paper shows as the design load of this bridge is low and the bridge has some defects，the load bearing capacity of the bridge can＇t satisfy request．So the bridge must be reinforced to enhance its load bearing capacity for ensuring the operation security of the bridge．

Research conclusions:From the application practice in engineering and comparing the calculation result obtained with Grillage Theory with the actual test result it is concluded the internal force and deflection needed in the load test can be realized by using Grillage Theory． The connection method of the cross beam is offered when establishing the model with the Grillage Theory． Finally，it points out that the impact of secondary dead load on the structure can not be ignored．The calculation values of the load test with this method fit to the tested values and it can provide the reference to the similar works．

Research conclusions:The load bearing state of the main girder is rational，the maximum absolute values of the tension and compression of the axial forces are close，and the born loads of all members of the bridge deck system meet the design requirements，the load bearing situation of the G11 joint is complicated，and the maximum stresses of all members do not exceed the yield stress．

Research conclusions:This four tracks railway wide－trussed cable－stayed bridge is featured with the large span of the cross beam for four tracks，the large bending moment of the end and middle parts of the span and the large bending movement transmitted to the outside of main truss surface．The research shows application of the trilateral truss without tie or vertical K brace can effectively reduce the span of the small cross beam and the outside bending moment can be born by two web nodals at the each lower chord point． Application of the deck system with horizontal K brace and longitudinal beam on the edge deck can improve the loading on the cross beam and main truss by changing load transfer channel to make main truss only bearing nodal load．Through doing the innovative research on the cross section of the wide truss，main truss style and the deck system with horizontal K brace and longitudinal beam on the edge deck，the difficult technical problem in design of the four tracks railway wild－trussed cable－stayed bridge have been solved successfully．

Research conclusions:The risk assessment is the reasonable way for correcting assessing the risk of the underground water under the condition that the current survey means is limited． The risk assessment of the underground water based on probability analysis presented in this paper is the important development and improvement of the previous assessment of hydrogeologic condition by taking quantitative calculation as the key point． The main factors of the underground water risk include the unstable surrounding rock and change of water quality caused by the volume and way of water bursting，the pressure of the underground water and the change of the underground water as well as the environment change caused by draining the underground water． The obviously local error often happens in the calculation of the hydrogeologic condition because of the uneven watery of the underground water． Conducting the risk assessment can reduce the risk of the big local water bursting caused by the error．

Research conclusions: (1) When the buried depth is in the range from 10m to 29m，the calculation results show the percentage of the quantity difference between the methods of the MUIR WOOD Equation and finite element gradually decreases with the increase of the buried depth． Although the calculation result of the 10m range is over big，it still can meet the requirement of the engineering design．(2) The internal force obtained with the MUIR WOOD Equation is conservative，but the calculation result can meet the basic requirement of the engineering design with the features of simple calculation process and common use． Especially in the early stage of the design，using the MUIR WOOD Equation to analyze the structure of the tunnel to be built can save the design time notably and enhance the design efficiency．

Research conclusions: With practical engineering，the design principle and structural characteristics of this tunnel are expounded; and on the basis of the study of the rock － slope mass structure features and deformation failure characteristics during this tunnel excavation，the deformation failure mechanism of this tunnel is elaborated; the interaction mechanics characteristic of the surrounding rock－supporting structure is systematically studied by numerical simulation method．The result shows that the coordination effect of the both is good，and the supporting strength is improved on the stress concentration area．

Research conclusions: Based on the drilling in the area of Keshiketeng Tunnel，the following points are concluded from the comprehensive analysis of the level and state of the ground stress in this area by using hydraulic fracturing technology area: (1) The maximum value of the level main stress should be bigger than the minimum level main stress and the vertical stress，and the level stress should be taken as the dominant factor．(2) The tested maximum and minimum level main stress should increase with the increase of the drilling depth and the NEE － SWW direction of squeezing should be taken as the dominant direction of the maximum level main stress．(3) As the ground stress of this area is distributed evenly，the measured stress is not high，so there is no possibility of happening rock outburst．

Research conclusions: The adjacent ( interface) constructions of the corridor and tunnel from above must be reported for approval according to relevant construction procedure． For the synchronical constructions，the construction sequences of " the engineering at lower place before the engineering at high place" and " important engineering before ordinary engineering" should be followed．For the shallow tunnel that its roof will collapse under the initial support due to the full～heavy weathered surrounding rock and long－span in，the surface grouting should be conducted first to ensure the safety of person and final implementation of the option．

Research conclusions:The temperature change of the core test piece of the mass concrete simulated by the small scale model was similar to the measured temperature change of the concrete in the center of the arch abutment and to the temperature change law of the numerical simulation． The original concrete model test is difficult to do and this method is new way to monitor and measure the temperature change law by simulating the temperature change of the mass concrete core with the small scale model，featured with easy operation，money saving，being good for doing the research on the mechanic property and durability of the mass concrete in lab，being helpful to master the temperature change law of the mass concrete core and offering the reference to similar works．

Research conclusions:(1) For confined by steel tube，the axial stress of lightweight aggregate concrete core increased greatly and the ductility was improved．At the same time，the axial stress of steel tube decreased rapidly for confinement effect． (2) Compared with normal concrete filled circular steel tubular (CFST) stub columns，the confinement effect of LCFST stub columns was weakened．

Research conclusions:Through comparing the transfer station with transfer on one platform for one station with the transfer station with transfer on one platform for two stations，it is believed the transfer station with transfer on one platform for two stations can satisfy zero transfer requirement． So the metro transfer station with large passenger flow of bi － direction should be the transfer station with transfer on one platform for two stations as much as possible if there is enough investment and there is only a little impact of construction on the urban transportation．

Research conclusions:This paper is an initial analysis of influential factors for programming of urban rail traffic．Main conclusions are drawn as follows: The integrated construction administration should make overall consideration．Planning department should have the consciousness of looking ahead into deep communication with research institutes about construction and operation problems，especially the planning control of the network，large quantity of land use planning in advance．Proprietor should actively coordinate with related departments to improving the stability，and feasibility of the blue print．Knowledgeable technicians and designers should thoroughly study every scheme，provide greatest plan for the proprietor to making decision，by comprehensive comparison in terms of technical and economic indices，The one－off tendering pattern should be adopted，therefore，strong motivation and enough confidence of the planning department will be excited．

Research conclusions:The open ventilation system is used in environment control system for the metro station in cold regions with open － close operational mode．A piston air tunnel and a bypass tunnel are setted up at each end of metro station． An electric start － stop device is installed in the space of about 500 mm between the top of high － security doors and the structural panel．In winter and summer，this device is closed to fully disconnect the track area with the public area of station for reducing the cold air volume from the station entrance and exit caused by the piston air．From the result of the simulation calculation it can be seen this environment control system program satisfies the climate features of the cold region

Research conclusions:Based on the analysis of the bandwidth requirement of the PIS wireless network，only the 802.11a technology or 802.11g technology can be adopted in PIS． The interference between PIS and CBTC can be avoided when 802.11a technology is adopted in PIS，and the interface and implementation of project are easier．But when 802.11g technology is adopted in PIS，the frequency of PIS should be different from the frequency of CBTC，and the project interface is increased．Possible interference from other wireless network should be considered simultaneously．

Research conclusions:The fluid － solid coupling effect of precipitation and excavation of deep foundation pit was analyzed and the coupling calculation model for the seepage field and stress field was established．The seepage － stress coupling simulation for the precipitation and excavation of the deep foundation pit in the first Yangtze River＇s terrace was carried out with FLAC3D．The calculation result showed that the the ground settlement formed a settlement groove of quadratic function curve，the seepage velocity was fastest under the diaphragm wall where the seepage and sabotage was easy to happen，and compared to the calculation with no coupling，the calculation result with coupling was more identical with the actual law and it could play a better role in prediction and informatization construction．

Research conclusions:By analyzing，energy absorbing equipment fixed in the traction substation can solve the contradictory that braking resistor cannot be fixed in the bottom of vehicle because of the limited space． It helps brake energy feed back to traction electric network and also can decrease the number of equipment in the vehicle．This way can save energy sufficiently but voltage rising will endanger the safety of equipments．So that，detailed elaboration is done to each part and function of circuit of energy absorbing equipment in this passage．

Research conclusions:The sorting management and bidding of the engineering materials are good for the market competition and lowering the construction cost． However，the high risk of the high price of the some engineering materials caused by the unclear sorting of the engineering materials and by the current settlement systems needs to be further researched and solved in order to promote the healthy and sustainable development of the high － speed railway in China with high quality．

Research conclusions:This paper developed an HeXie management model of the large － scale railway construction based on supply chain．On this model，the organization of the engineering supply chain can achieve the HeXie theme—the“six in one”performance goal by the control mechanism and evolution mechanism．Meanwhile，the satisfaction degree of the feedback，adjusting mechanism，their long － term and stable demands from the organization of the supply chain，can ensure interaction and circulation improvement between the HeXie theme and project performance，then improve the performance of railway construction project constantly．