Research conclusions: The experimental results show that the large sight stereo model build with this method has good visual effects. Its calculation method is simple and easy to realize. Its measurement accuracy is good as the measurement accuracy of the digital photogrammetric workstation in same scale. So it is available for the railway alignment and engineering design, and with it the design works can be directly done in the 3D stereo environment.

Research conclusions: Based on the technologies of the train control system level 2(CTCS -2), the train running monitor and record device (LKJ) and the ground signals，the analyses and calculations were made for the minimum headways between trains into the Yuncheng North Station of Datong-Xi an PDL by using the calculation model. The calculations show the 3 minutes headway of the arrival-running through，the 3 minutes headway of the arrival-arrival and the 3 minutes headway of the running through-departure between the common passenger train and the EMU can be realized. And the 5 minutes headway of the departure-departure between the EMU and the common passenger train can be realized.

Research conclusions: The real collapsible thickness of loess depends on a variety of factors and the major factor is the soaking condition. Under the concrete soaking condition, the thickness of saturated collapsible loess is controlled by the precipitation, penetration of surface water and rising of ground water. The experience and calculation show the most soaking thicknesses under natural environment are obviously less than the thickness of the collapsible loess. By taking the soaking collapsible thickness as the basis, the construction cost and works can be much reduced. The calculation and analysis of the soaking thickness under natural environment presented in this paper can give a new method and thinking on valuation of the loess collapsibility and grading the soaking environment.

Research conclusions: The analysis showed that the mortar existing in this area was caused by casting the concrete to the pile by two times. The concrete could be casted to the one pile by one time. At the same time，the casting of concrete to the pile could be continuous and the stratification of more than Im could be avoided. The vibration rods would be used for the hierarchical compaction. Additionally, more attention would be paid to the construction quality of the remaining wall and the concrete slump would be controlled at 180 mm. It would make sure that there was no sediment on the pile bottom and there was no water leakage of the remaining wall. If it was necessary to cast the concrete for the second time, the second integrity test to the pile would be done to ensure that there was no mortar on the pile top casted by the first time. For the cutting subgrade, the anti-slide piles would be completed before excavation of the subgrade. For the same row of the pile, the interval construction was needed. In the process of the construction, the second batch of the interval piles could not be casted until the 28 days later after the first batch of the piles were casted.

Research conclusions: Usually, when the cutting subgrade passes through riverside with the excavation depth below the water flood level, the scheme of the watertight curtain should be chosen on consideration of the technological, economic and safe factors to reduce the influence of adverse factors on the new railway as much as possible. This is one of the ways to deal with the problems in such project. In the choice of the scheme, the misunderstanding of blindly seeking the low cost should be given up, and the high performance to price should be sought.

Research conclusions: (1) By simulation calculation, the recommended values of the limit error of lateral and longitudinal chord lengths were determined and they were separately 1 mm and 2 mm. With these data, the verified tests were done for judging the stability of the retesting control points. The judging method was as follows: When the limit error of the lateral chord length between the adjacent control points of CPⅢ did not exceed the limit of 1 mm, it showed that at least the stability of one control points was poor. For further confirming the stability, it needed to see whether the limit error between the longitudinal chords lengths of these two control points and their adjacent CPⅢ points exceed the limit of 2 mm or not. (2) The testing results showed that the conclusions obtained by using the method presented in this paper were consistent with that obtained by using the methods stipulated in the current codes, so this method was feasible and the research result could provide the reference to working out and improving the specifications for retesting CPⅢ.

Research conclusions: In the highway's section with the large longitudinal slope of more than 3%, the gentle slopes should not be designed frequently. The emergency lane should be built when the elevation difference of one large longitudinal slope reaches at 130 meters. In addition, the warning signs should be added and the slow lane should be built in the conditional section to reduce the driving risk and protect the driver and the other people.

Research conclusions: The research results show that the natural frequency of the track system decreases with the increase of the thickness of the ballastless track, and the rate of change decreases with increase of the track thickness. The acceleration insertion loss of the track basis increases with the increase of the thickness of the ballastless track，and the rate of change decreases with increase of the track thickness. When the thickness of the ballastless track reaches at 0.4m，the corresponding dynamic performance，the damping performance effect and the concrete amount of track bed are rather economical. From the present theoretical analysis and online testing, it can be seen the damping performance effect of the isolated rubber floating slab system is obvious，and its construction and maintenance programs are systematic.

Research conclusions: With the new rotational penetration test technology applied in survey for a super big railway bridge in Nangang of Tianjin, the penetration depth reached at 80m. The application showed this technology overcame the conventional static cone penetration tests demerits, such as unable to penetrate the hard and deep stratum and the shallow testing depth, met the needs of the engineering design and the rotational cone penetration was an in-site test method available for railway and the high-rise building.

Research conclusions: From the research，we can draw the below conclusions: (1) The differences and the relation between the seismic rules of the highway bridge stipulated in the new version code and the 2008 version code can be seen. (2) For calculation of the bridge with the plastic working state, the following procedure should be followed: First, the section dimension can be increased to control the deformation, then the rate of reinforcement can be adjusted to make the piers yielding and finally the capability protection members are designed.

Research conclusions: The continuous beam-arch combined structure has the merits of both long - span continuous beam and arch. Combined with the same large span continuous beam, the height of the main beam can be lowered because of the arch effect. The pressure-resistant and deformation-resistant capacities of the concrete are much enhanced because of the hooping effect of the steel tube on the concrete. The stability of the steel tube is improved because of the concrete in the steel tube to make the arch and beam being able to bear the loads. So the beam-arch combined structure has the features of the good capacity of bearing load，the good stiffness of the structure，less height of architecture and mature construction methods, and this type of bridge will become one of the most competitive bridges.

Research conclusions: The analysis results illustrated that on consideration of the additional settlement of foundation caused by the newly building bridge ,the maximum unequal settlement of the adjacent solid pier structure of the existing Beijing-Shanghai High-speed Railway was 3.2mm and the frame pier structure was 4.3mm, and they were in the regulatory range of 5mm and feasible. It was recommended to use the solid pier structure because its additional impact was lesser than the others. In addition, it was proposed that the settlement influence on the existing high-speed railway bridge could be further reduced by extending the length of pile foundation of the new bridge properly and it also pointed out there was a variation between theoretical calculation and real data，so the perfect monitoring scheme，method， control value and early warning value would be established and improved to ensure the safe construction and safe operation of high-speed railway.

Research conclusions: (1) The calculation and heaped loading test showed the strength，stiffness, manufacturing quality and assembly quality of the movable die carrier met the design requirements and the pre-camber was reasonable according to the y=0.1213x2-30.1. (2) The movable die carrier had the features of the clear loading on the structure, good adaptability, perfect functions and high mechanization. (3) The movable die carrier met the construction requirements for the 24 m box girder, the curve bridge, the bidirectional 32m box girder with assembly of integrated 32 m bridge opening.

Research conclusions: (1) During the exploration and design stages, the CSAMT method is mainly used for exploring the 40m deep ground，the corresponding geophysical exploration methods should be used for exploring the ground of the less than 40m depth, and the multiple coverage seismic reflection wave method should be used for the geological exploration for the subaqueous (submarine) tunnel. (2) During the construction stage,the electric sounding method is used for exploring the tunnel base，the hole-crossing elastic tomography method is used for exploring the area with density distribution of coal goafs，the EM tomography method is used for exploring the karst area，especially for the karst with good development, the TPS method is used for the advanced geological forecast to the area in front of the working face of the tunnel，and the ground penetration radar is used for inspection of the lining quality of the tunnel.

Research conclusions: The Chahe tunnel was a typical case that the tunnel became and developed into a landslide tunnel due to the joint effects of the unsymmetrical pressures of terrain and the geological structure. The special terrain and the slope geological structures and the geological characteristics of each soil layer made the slope easily to be pressured unsymmetrically. The soft and weak sliding zone formed along the bedding surface and the high-angle fault surface were the internal factors of the landslide formation. The river erosion, the rain infiltration and especially the intermittent declining movement of the hanging side of the F1 high-angle normal fault caused by the structure movement and seismic action were the important external triggering factors for the formation and development of landslide. The respected treatment effect can be achieved by doing the comprehensive treatments according to the investigation conclusions and suggestions.

Research conclusions: The TSP forecast technology was used for the Lijiaying Tunnel and it worked well. The forecast results proved that by using the TSP method, the geological conditions of the area within 100-150 meters in front of the working face of the tunnel could be well known timely, and also the forecast result could be sent timely. Meanwhile, the applicable procedures of TSP forecast method were so simple that it was possible to carry on the forecast work without the influence on the tunnel construction. With the TSP technology, the basis could be provided to the tunnel construction and parameter adjustments to guarantee the construction safety.

Research conclusions: From the research on the actual terrain condition and the 3D FEM model for the design of the tunnel lining, it was seen the maximum additional displacement of the railway tunnel was about lmm, the maximum additional stress of the tunnel was 1810 kN*m/m and the maximum horizontal displacement of the highway excavation face was about 41.0mm. On the premise of well doing the works of construction organization and monitoring, the safe operation of the railway could be archived. It was also proposed that the excavation could be symmetrically conducted section by section，zone by zone and layer by layer and the appropriate adjustments of the construction procedures could be made according to the monitoring data to further reduce adverse effect on the tunnel.

Research conclusions: An analysis program was compiled for the Japanese steel cantilever structure with finite element method and ANSYS software. Combined with the standards and real project condition, the results of the static and modal analyses to the Japanese steel cantilever structure were studied. The result showed that the Japanese steel cantilever support structure had a lot of merits，such as the less deflection after loading and being uneasy to produce resonance due to the strong overall stability, and its static strength met the design requirements. So it has good applicable prospecting.

Research conclusions: (1) Under some limiting condition，the back-returning capacity of the two common forms can't meet the need. (2) The paper has done some analysis and computation on a peculiar yard type and its back-returning mode，the result is that its back-returning capacity can reach 40 train pairs. (3) This back-returning mode has some advantages and adaptability.

Research conclusions: Based on the investigation of the current conditions and the analysis of the reasons for the difficulties, the difficult problems in coordination of the Line 8 with the OTC is overcome by taking the countermeasures, getting the good results. (1) Compared with the construction planning，the track length is shortened and the project investment is saved by 2.1 billion yuan. (2) By reasonably setting up the stations, the OCT branch lines and the Line 4 can cover the surrounding areas, and it can promote the rapid development of the region. (3) The floor of the property development increases by 29,150 square meters and the commercial value of the subway is enhanced.

Research conclusions: Through the analysis of the functional orientation, transfer distance, passenger flow and distance between stations of each line，and based on working out and taking the countermeasures，the importance of the three line transfer was presented and the merits of centrally setting up stations for three lines was analyzed. In this way, the difficulties in construction and coordination were overcome，obtaining good results. The following conclusions are drawn: (1) The three line-transfer in Hong Kong Road Station is necessary because the Line 3，Line 6 and Line 7 meet here. (2) From the transfer function and the influence of station construction on surrounding environment, the central setting up station for 3 lines has certain advantages，but the attention should be paid to the positions of the escalators，exits and entrance to make the transfer passage smooth.

Research conclusions: Now the problems caused by the pipeline crossing and paralleling with the metro track become more and more, so the pipeline operators should cooperate with the metro operator. (1) The metro designer and operator of the metro should control the total volume of the stray current，monitor the internal system and discharge the current to make the stray current in the certain range with on impact on the external system. (2) The pipeline operators should insulate and cathodically protect the pipeline. In the area where the pipeline crosses or parallels with the metro track, the monitoring spot should be added, the corrosion-proof coating should be thickened and the anodic discharge current should not be conducted.

Research conclusions: From the research it is concluded: (1) On considering that the property resources can not be used as the capital under the current policy, it is proposed the government should set up a construction fund or make a promise of the financial investment for urban rail transit to avoid the capital risk and obtain the approval of projects. (2) The construction and operation of the blinded subway with the property should be evaluated as the comprehensive project. (3) The following points should be considered in the economic evaluation: The internal rate of return should be oriented from the cost of the market capital and on considering the a certain risk investment，it should be a little higher than the bank long-term loan to attract more social capitals. (4) The incremental benefits deducting the property development cost and the amount of contribution of the subway capital can be regarded as the "resource income" and go into the cash inflow，and the inputs and outputs of the other items should be calculated according the subway mode.