Research conclusions ： By doing the numerical calculation，the analyses of the stress change regulation and the influence of the slope shape on the loess slope stability were made to monitor the displacement variation characteristics of the empty surface and internal parts of the slope body. The result showed ： (1) The upright side wall was harmful to the slope stability, and the maximum displacement appeared on the top of the upright side wall. (2) The overall stability of the slope with the upright sidewall is not only affected by the slope of the excavation depth，but also by the slope ratio of the secondary slope adjacent to upright sidewall. When the slope excavation depths were the same, the small the slope ratio of secondary slope was and the better the overall stability of the excavation slope was. (3) To ensure the excavation safety of the temporary loess slope in the open cut exit of the Hanguguan Tunnel of the Zhengzhou – Xi′ an High — speed Railway, the straight slope was used, with the upright sidewall height of 9 m and the secondary slope ratio of 1 : 1. The research results can provide the scientific basis for the similar works.

Research conclusions ： (1) As the slurry permeated, split and compacted into the holes and cracks in the goaf, the concretions were formed in the bending crack and fissure zones when the boring grouting was used. In this way, the foundation strength was improved effectively and the settlement and stability requirements of the railway foundation were met. (2) The dynamic design was used for treatment project and the project was divided into two stages. The first stage included the exploring and pouring of the combined holes, the holes, curtain grouting holes and the test section. The second stage included the exploring and pouring of the II and HI holes according to the parameters of the first stage. This design scheme was proved feasible. (3) The design and construction of this project can provide the guidance and reference to similar reinforcement projects in the future.

Research conclusions ： (1) The shear stress in the bonding section is distributed in the light of exponential curve form of the single peak in stead of unevenly distributed form when the anchor is loaded. The recursive control anchor can disperse the concentrated load into several smaller loads on the different bonding sections among the sliding masses to make full use of the formation strength of the free segment. (2) The results of numerical simulation are basically consistent with the results of the qualitative analysis and model test. It shows that the numerical simulation of the anchor action process is feasible, (3) The recursive control anchor can overcome the traditional anchor's shortcoming that the counter - force load is entirely borne by external anchor structure and can reduce the size of external anchor structure effectively. (4) The research results can be applied in the slope reinforcement and quick treatment of the disease.

Research conclusions ： (1) The collapse and uneven settlement are easy to appear to the foundation in collapsible loess area and the loess subgrade slope is the place where the water loss and soil erosion happen frequently. (2) In order to improve property and capacity of the deformation resistance of the railway subgrade in collapsible loess area and enhance the overall stability of the subgrade，the loess foundation must be treated specially and at the same time the slope protection must be conducted effectively. (3) The loess foundation treatment methods include the backfilling, the heavy rolling, building the sand cushion, heavy compaction, building geogrid and other forms. (4) The control of the Filling material is very important to the slope protection of loess subgrade and it incluses the controls of the particle size, moisture content, degree of compaction and so on. (5) The construction organization design presented in this paper, especially the measures for the subgrade reinforcement and the slope protection are available for the subgrade construction of heavy - haul railway in gravity - type loess area.

Research conclusions： (1 ) The stiffness homogenization in turnout area is particularly important to the regularity, safety, comfortableness and service life of high — speed turnouts. (2) For the France's turnouts, the stiffness homogenization is achieved by increasing the rubber pad stiffness, and this method is simple without using the transition section. (3) For the Germany^ turnouts, the elasticity of the pad is controlled strictly by vulcanization, and both the design and manufacture are complicated. (4)For the China's high - speed turnouts, the turnout is divided into different sections according to different structure, and the stiffness homogenization is achieved by vulcanization. (5) Although the measures taken by the countries are different, but the stiffness homogenization in turnout area are achieved in different countries. (6) The turnout dynamic test and application show the method and measures used for the stiffness homogenization of the high — speed turnout in China are reasonable and feasible.

Research conclusions: (1) This track - laying machine unit integrates the long - rail track laying and the tie arranging， and is mainly composed of the long rail tractor，the host and auxiliary machines，tie carrying car， rail /tie transportation train， power system， hydraulic system， electric control system and brake system. (2) The operation mode of the host machine is designed as the " arranging the tie in cluster and laying the track in step" by using the innovative mechanism of the laying the tie evenly and sleeper arranging machine， and by using this method， the problems of high failure rate and the tie damage caused by the impact can be solved and the costs of the machine manufacture， operation and maintenance can be much cut. (3) The modularization design and manufacture are adopted to this machine unit，resulting in convenient and flexible assembly， disassembly and transferring to other site. (4) This machine machine is made in Chins with adopting the existing mature technology for long rail track laying， computer control technology and the mechatronics technology， so that the convenient use and maintenance can be achieved. (5) This research results is available for laying the ballast and ballastless tracks with the 500 m long rail or below.

Research conclusions ： ( 1 ) Based on the actually measured impact coefficients of the bridge vibration tests of the concrete filled steel tube structures of three railway bridges，the suitable formula for calculation of the impact coefficients on such kind of bridge under the active load of train was got by fitting to ensure the calculation reliability of the stress amplitude under the active load. (2) The introduction was given to the geometric and physical technical parameters and stress concentration coefficient of the tube segment and the stipulation of classification the fatigue details. (3) The static test and fatigue test of the tube segment structure were conducted. Based on the analyses of the test data of the segment between tubes and tube segment, the simple and practical fatigue test methods for the segment between tubes and the tube segment were presented for the fatigue design of concrete filled steel tube structure of railway bridge. (4) This research result is available for the concrete filled steel tube structure of various bridges.

Research conclusions ： (1) Because the hydraulic integration adjustable bracket was installed on the double thin - wall top，the problem of adjusting the bracket height was overcome，so the safety risk of the support construction was reduced and the construction safety and quality of long, high and heavy original section was guaranteed. (2) A concrete self--supporting bracket system was used in bridge contact network platform, so，the foundation construction of flange could be conducted simultaneously with construction of the catenary support. In this way, the engineering cost was reduced and construction time was shortened. (3) The C55 polypropylene fiber concrete was used to improve the crack resistance of the concrete. The layered pouring and reasonable process were adopted to ensure the construction quality of the concrete. (4) This research result is available for construction of the railway high - pier long-span continuous rigid frame bridge and single T rigid frame bridge.

Research conclusions ； (1) By making the feasible geological prediction，the accurate geological situation was obtained. By making the FLAC3D numerical simulation and comparison of the excavation schemes with bench method, the 6m step height was easily chosen. Based on the controls of the stratum deformation and tunnel stability, the reasonable 2 m excavation footage was adjusted with the help of the FLAC3D numerical simulation, and the reasonable step length was 10m. (2) In order to meet the requirements of the strength, stability and durability, the composite lining was adopted to the service tunnel of the Xiamen Xiang an Tunnel. (3) For the monozonite veins section, by monitoring and measuring the subsidence of the crown and the convergence of the cave，the rationality of the scheme and the effectiveness of specific measures were verified．(4)The key technology system of the excavation，support，geological prediction and monitoring and measuring for the Xiamen Subsea Tunnel can provide the referenee to construction of submarine tunnel across monozonite veins section or weathered rock section．

Research conclusions ： (1) As the soil physical parameters change，the stratiform expansion of soil mass will bring about the change of the outside pressure on the structure and generate the additional load. This expansive load is related to the expansion force and the free expansivity of the expansive soil. (2) When the stratiform expansion of expansive soil mass appears above or below the tunnel, the expansive load is small, and is less affected by the expansion force, thickness of expansive soil and distance between tunnel and expansive soil mass. (3 ) When the stratiform expansion of expansive soil happens on both sides of tunnel, the outside pressure on the tunnel structure increases largely, and the load increases with the increase of expansion force of the expansive soil. However, a certain expansion scope and expansion force are beneficial to the load on tunnel structure. (4) The research results can be used for guiding the sampling values of expansive load in design of shield tunnel structure.

Research conclusions ： (1) This new type of single turnout of the 60 kg/m rail has the straight switch rail，straight frog， and circular curve, with the simple structure. (2) Two switch rails are symmetrical, and can be pulled flexibly.(3)This turnout is available for the siding speed of 35 km/h，with less maintenance. (4) This research result has obvious advantages in the mature technology, reliability and security, and it is available for the metro, light rail and trolley car.

Research conclusions ： The research was done on the suspension and fixing of the catenary under the upper cover platform of the Tanglang Vehicle Depot of Shenzhen metro on learning the suspension and fixing modes of the catenary in the high - speed railway tunnel. From the research，it is concluded ： (1) The crossing suspension mode should be adopted to the catenary under upper cover platform of metro vehicle depot. (2) The structure of the embedded C shaped steel (channel) should be adopted to the catenary under the upper cover platform on determination of the technical parameters and requirements of the C shaped steel embedded parts. (3) The design plans of the various embedded parts corresponding to the contacting suspension and fixing (crossing fixing cable, hoist cable and cantilever, etc) and installation of the anchor and isolation switch were determined on the research. (4) From the angle of the project management, the analysis was made for the advantages of the structure of embedded C - shaped steel mode for the catenary’s suspension and fixing. The proposal was made that this mode would be widely used in the catenary engineering.

Research conclusions ： (1) The settlement of the bottom plate structure of the existing station is affected by the release of stress of the working face, the disturbance to bottom during excavation，the excavation height，the long closure time of the primary support structure and no timely jacking of the jack，and the release of the stress of the working face is the main reason for the settlement of the existing structure. (2) The settlement of the existing structure can be effectively controlled by taking the measures of adding the temporary columns and jacks，reinforcing the foundation base with steel frame, grouting to the back of the primary support with extreme fine cement paste and jacking up by jacks, and the jacking up by the jacks is the most powerful means to control the settlement. (3 ) The CRD + top brace control technology is available for effective control of the settlement of the existing station and meet the settlement of 3 mm.

Research conclusions ： The revision trend of the normative gradation scope has proved that the S - shaped embedded crowed skeleton gradation has been generally accepted in a certain extent. To control the cost of bituminous mixture to the lowest level，the design of the bituminous mixture composition should fully consider the raw material cost，the production cost of the mixture materials, the construction cost and the later-stage maintenance cost. In the allowable circumstances, the coarse aggregates VMA should be designed as small as possible, and the overall clearance rate of the mixture materials should be adjusted by adjusting fine aggregate and filling material so as to optimize the performance of mixture materials.

Research conclusions ； (1) The equilateral triangular network is generally used for the configure of the blast holes when the diving drill is adopted for the open - air blasting of the roadbed rock. It has the obvious advantages that the blasted rock blocks are even with the small amount of the under-blasted and over - blasted rocks. (2) The configuration of blast holes and the distance between the hole rows are closely related to the the diameter of aperture. Regarding to the diameters of the rock and drill ( diameter of aperture) , there is a reasonable range for the distance between the two ad?joining hole rows. If the distance of hole configuration exceeds this range，the flying rocks，larger rock blocks and even hopper blasting may happen in blasting. (3)This research result is available for the open - air blasting of the roadbed rock with a good effect.

Research conclusions ： (1 ) The seed - nutriment - soil sacks technology presented in this paper is available for the ecological restoration of alpine steppe along the railway. (2)The plant species of the Poa ciymophia, Elymus nutans and Elymus sibiricus were used in the tests，getting the good joint effects. The stable phytobiocoenose was form in the second year after the project. The amounts of seed plant of Poa ciymophia，Elymus nutans and Elymus sibiricus were separately 0.5g，4g and 4g. (3) Adding the water - absorbent polymer and organic fertilizer in the planting matrix got obvious effect. (4)The research results could be applied in ecological and geological disaster prevention and control projects for the transportation construction in permafrost regions of the Tibetan plateau.

Research conclusions ： The constructions of railway and highway, large -scale blasting，disordered mining and freely drainage and seepage of the water by residents were the main risk factors for the landslide. The size of the landslide was not well known and the most unfavorable sliding surface was not found ； The engineering measures were not taken perfectly. The risk of the landslide of the railway subgrade in the landsliding area along with the entire landslide was recognized as high risk level. According to the main risk factors of the landslide risk, the countermeasures of using anti -sliding pile，slope protection，building the ring intercepting ditch and filling the tension crack by clay soil were taken to ensure the safety of railway subgrade in the landsliding area.

Research conclusions ： ( 1) There are lots of uncertain factors that influence the target of the general contracting during the construction because of the features of the metro construction under the general contracting mode. The risk features of the general contracting, as the basis of the risk management, decide the risk management thinking and the way for dealing with the risk. (2) The IATM was built, the standards for the risk management were worked out and the risk management procedure was normed for providing a complete set of methods and procedures for the risk management to realize the looped risk management. (3) The risk monitoring and control systems were built to urge the corresponding departments to monitor and control the risks，adjust the risk countermeasures and the key emphasis in work according to the risk level, and focus on the prevention and control of the main risks for effectively controlling the risks. (4) The risk management is an important part of the project management. Strengthening the metro risk management under construction general contracting mode is very important to enhance the project management benefit and the management level of metro construction in China.

Research conclusions ： (1) The more attention should be paid to the technical characteristics of EPC project and the particularity of total price contract. The requirements of the owner and contract should be met with small cost. (2) The design scheme should broadly consider the interests and benefits of the project and the interests of all parties involved should be taken into account，especially the contractor. In addition，the technology，risk and investment control should be balanced. (3 ) The good strategy should be used to push on the change plan step by step and from easy area to difficult area on full consideration of the concerns of the owner and supervisor to persuade them to understand and accept the design scheme that is favorable for the all parties. (4) This research result can be as the reference to the similar works.

Research conclusions ： ( 1) Analyze the market environment objectively，recognize the substance of EPC product and establish the objective of localization so as to promote the transformation of economic business from internal - oriented mode to export 一 oriented mode; (2 ) Analyze the production factors of EPC product carefully，understand and master these resources so as to complete the transformation of role from a contractor to an integrator； (3) Grasp the key processes, and stick to the " design - led" and " contract - based" principle so as to achieve the target that the implementation risks of EPC projects are controllable. (4) These research results can be applied to preliminary decision — making, project management and other works of large - scale overseas EPC projects in fields such as transportation construction, electric power construction, petrifaction and chemical engineering, mining development, etc.