Research conclusions:(1)The main geological problems of the Lanzhou rail transit included the stability of the surrounding rock, the engineering water disaster, the seepage deformation, the engineering ponding after completion of the tunnel construction and the foundation settlement. (2)The various engineering problems faced in construction of the Lanzhou rail transit could be overcome or controlled by making the reasonable design scheme and taking the corresponding construction measures, such as using the New Austrian Tunneling Method, the shield tunneling method, the open cut method, the top-down method, the underground diaphragm wall and the isolation piles etc. (3) The various technical means should be used for the geotechnical survey for the rail transit. Besides, the routine geotechnical mechanics parameters should be well known, the parameters like the resistivity and foundation bed coefficient should also be considered. In addition, the differential and corresponding surveys should be conducted for the different construction methods. (4)This study results can be applied in treatment of the engineering geological problems in construction of rail transit.

Research conclusions: (1) The main types of slope diseases include the collapse, landslide, slumping, fault and rockfall. Collapse is the major disease, up to 71% of the total slope diseases. About 80% diseases happens to rock slope. (2) The deformation failure modes of collapse have 8 types like pull cracking and falling. Landslide has 5 types like pull cracking, shearing off and sliding. Slumping has 2 types of shaking loose and slumping. Rock falling has 2 types of throwing and dropping. Disorder falling has 1 type of shaking to crimping. (3)This research result can provide the reference to prevention and control of the slope diseases caused by earthquakes along railways and roads.

Research conclusions: According to the characteristics of the collapsible loess of the Zhengzhou-Xi'an Passenger Dedicated Line, by making the theoretical analysis and doing the centrifugal model tests and field tests, the research was done on the adaptability and effect of reinforcing the collapsible loess foundation with the pile-board structure of subgrade, cement soil column hammer impact-expand pile, cement soil compaction pile and CFG pile. From the results it is concluded:(1)The overhead and framing pile-board structure has a distinct advantage to reinforce the deep collapsible loess foundation or short collapsible loess foundation between bridge and tunnel.(2)The cement soil column hammer impact-expand pile is available for reinforcing the medium deep collapsible loess foundation.(3)The cement soil compaction pile is available for reinforcing the shallow collapsible loess foundation according to the limited conditions.(4)The cement-flyash-gravel pile(CFG pile)is available for reinforcing the collapsible loess foundation with small diameter and distance.(5)The research results can provide the reference to the reinforcement of the collapsible loess foundation.

Research conclusions: (1) The calculating result of determination of the critical height of a embankment is more authentic on consideration of both the internal friction angle and the cohesion at the same time.(2)The calculating analysis shows the critical height should not be designed in the way of reduction of 2-3 m of the filling critical height and it should not be designed only on consideration of the filling critical height, but it should be designed on full consideration of the filling height, slope ratio, the train load and the ground parameters. Otherwise a conservative design will be made. (3)In the previous methods，the soil internal friction angle and cohesion are seldom considered, therefore, they have certain limitations. (4)The calculation formula presented in this paper on consideration of the soil internal friction angle and cohesion at the same time can be used for the preliminarily determination of the critical height of the embankment on the soft soil.

Research conclusions: The pile-slab structure-foundation-subway numerical model was built to make the dynamic simulation analysis and study the dynamic response characteristics of the system under the condition of loading on two coaches on the single track. The results showed: (1)With increase of train speed, the acceleration of the measured point increased Linearly, the dynamic stress increased exponentially and the dynamic displacement decreased linearly. (2)The dynamic response caused by the excited force decayed quickly through the bearing plate, the joists, the pile foundation and the soil around the pile, so the dynamic response to the subway lining structure was very small. (3)Under the effect of train excited force, the peak value of the subway increased linearly with increase of the train running speed, and the maximum value was about 0.96 cm/s and it satisfied the specification requirement. (4)The three-dimensional dynamic simulation result was very close to the real tested value. So the dynamic numerical model is reliable for making the dynamic analysis of the pile-slab structure-foundation-subway system and is feasible for studying the dynamic characteristics of the pile-slab structure and evaluating the safety of the subway structure under the effect of the excited force of train.

Research conclusions: (1)Application of the fast detection system for the foundation plate of the ballastless track of high-speed can much enhance the construction measurement efficiency and facilitate the quality control during construction of foundation plate.(2)The detailed and objective data can be provided for the intermediate acceptance, and the detection methods with the independent intellectual property right have been formed during the research.(3)The combined test way and method are found for the relative and absolute benchmark measurements，and it fills the technological blank in this field and promotes the innovation and development of the automatic measurement equipment for construction of high-speed railway in China. (4)The detection system presented in this paper solves the quality control problem in construction of ballastless track of high-speed railway and can provide the reference to the similar project.

Research conclusions: (1)The analysis of wind pressure calculation of the EMU shows when the midway between tracks is 4.4m, the erecting equipment is in the stationary state and the speed of the EMU is at 165 km/h, the maximum amplitude of pressure fluctuation generated by the EMUs meeting is 637. 15 Pa and it is less than the allowable instantaneous pressure wave value of 900 Pa of the midway between tracks. The EMU's window structure and glass are in the safe and reliable state and the equipment has the high stability. (2)By adopting the method of blocking track for 5 hours to erect 1 beam or laying 300m long track panel, the laying and erecting works can be done in small midway between track of 4.4-6.5 m from the existing railway track. In this way, the construction safety and quality are guaranteed, the construction cost is cut and the construction period is shortened. (3)This research result can provide the reference to both small railway line spacing range of additional second-line construction technology.

Research conclusions:(1)Compared with far-fault ground motion and non-pulse-like motion, the directivity pulse-like Near-fault ground motion had a big influence on the seismic responses on the short-period structure, increased the displacement response of inelastic bridge structures and it also increased the structural and nonstructural damage because the hysteretic properties of the near-fault directivity pulse-type earthquake was characterized by the central strengthened hysteretic cycles.(2)The big vertical acceleration of near-fault directivity pulse-like motion could notably change the axial load of the bridge piers, resulting in big increase of vertical deflection in the mid-span of girder, but the vertical earthquake force is specified as 65% of the lateral earthquake in the 《Code for Seismic Design of Railway Engineering》 (GB 50111-2006) and it causes the smaller vertical deflection in the girder. (3)The calculation results could provide the reference to the seismic design of high-speed railway bridge, and provide the technical support for the revisions of the design specifications and standards.

Research conclusions: From the analysis of the calculation example, it is concluded: (1)For bridge pier with pile foundation on slope, the horizontal resistance of the slope has rather big influence on the pile foundation bearing the load and the displacement and stress of the pile foundation are of nonuniformity along the slope. (2)For multi-layered soil slope, the displacement and stress of the pile foundation sharply change in the parting region of soil layers and the pile foundation has an unfavorable load bearing area in the parting region of soil interlayers. (3)The research method and results presented in this paper can provide the reference to design and mechanical analysis of the pile foundation of bridge on slope.

Research conclusions:(1)The diabase is rich in kaolinite, with the engineering properties of low strength, easy disintegration and weak expansion, but it is dilatable along the unloading direction under the unloaded stress path.(2)The distribution of the diabase dikes has the significant effect on the magnitude and distribution of the rock pressure. The pressure of the surrounding rock with exposing more diabase section is bigger than that with exposing less diabase section, and the pressure of the exposing part is bigger than that of the adjacent parts without exposure.(3)The distribution of diabase dikes also affect the tunnel deformation significantly. The settlement of the vault with exposing the section is larger. In the section of exposing the diabase on the dome, the convergence deformation of the sidewall is larger. In the section of exposing the diabase on the sidewall and arch, the tunnel deformation lasts longer. (4) In the section of exposing more diabase, the large tunnel deformation contains the swelling deformation and compressional deformation. (5)This research result can be available for the design and construction of tunnel in diabase zone.

Research conclusions:(1) By using the thermal probe group, the temperature of the surrounding wall will be significantly reduced within its sphere of influence, the strength of the surrounding wall of permafrost will be enhanced, and the top limit of the permafrost will be raised to form a waterproof curtain on the tunnel ceiling for reducing the frost heaving force on the tunnel supporting structure.(2)The water above frozen layer can’t infiltrate into the tunnel structure and the refreezing time will be reduced from 3 to 5 freezing and thawing cycles to 1 cycle. In this way, the problem of the freeze-thawing damage to the supporting structure in the portal section can be solved.(3)This technology has features of lower engineering cost and more convenience in terms of installing and monitoring. (4)This research achievement can be used for the disease control and treatment of the shallow section of tunnel in the permafrost area.

Research conclusions: (1)Grouting is an effective method for control of the water and mud bursting of railway tunnel, and the principle of the “grouting reinforcement along with drainage and dropping pressure" should be followed. (2)In order to obtain safe, efficient and economic control effects, a comprehensive control means of the grouting improvement, reinforced anchorage and large pipe roof construction should be adopted with informatization grouting technology and professionalization management.(3)This research results can be applied in control of the water and mud bursting disaster.

Research conclusions: (1) The maximum ground settlement for every increased 0.1% of strata loss was increased 3-4 mm under the condition of strata loss 5 %. (2) The final settlement for every increased 0.5 % of average strata loss of shield tail was increased 8mm. (3) By the common influence of strata loss of shield head and shield tail, the total final settlement was formed.(4)It is proposed that development of a set of methods for shield control by using ground settlementin dicators of strata loss control rate.(5)This paper provides the valuable reference to the study on the ground settlement , disaster prevention, tunnel design, and construction.

Research conclusions: Before remolding of the shield cutter head, the maximum surface subsidence was about 17.0 mm, the transverse influence range of the surface subsidence was about 40 m on each side of the tunnel centerline, the longitudinal influence range of the surface subsidence was about 1.25 times of the tunnel diameter in front of the tunnel working face and 4.15 times of the tunnel diameter in rear of the tunnel working face and the maximum transverse and longitudinal displacements values of the deep soil on both sides of the tunnel were 11.0 mm and 6.8mm respectively on the horizontal plane of the tunnel center. After remolding of the shield cutter head, the maximum surface subsidence was reduced to 8.0 mm or below and the horizontal displacements of the deep soil on both sides of the tunnel were also reduced. It can be seen the surface subsidence can be effectively controlled by remolding of the shield cutter head. The peck equation matched the surface groove curve before and after the remolding of the shield cutter head. However the changes took place in the strata loss rate and width coefficient of settlement trough. This research results can provide reference to the similar projects.

Research conclusions: (1) From the analysis and the test run it is concluded: The Metro Group Co. Ltd. Can intervene to manage in time due to the timely issue and transmission of design progress information in the test run, and the great majority delay have not affected the construction on site, and the proportion of construction progress delay due to design has reduced to 15%. (2)The function of design change has not achieved yet due to the lack of standardization of the workflow of all participant. The information technology can't solve any management problem and the premise of the success of management system application based on PIP framework is the normative plow and a higher level of management by the proof in practice. The management system mentioned in this paper is applied to the design management in metro construction, and can increase the design management efficiency effective.

Research conclusions: (1)The FLAC simulation showed that with the excavation of the pilot tunnel, the settlement of the ground surface gradually increased. The curve of the settlement groove gradually changed from double peaks to single peak due to the influence of the load of the upper bridge and the dead weight of the bridge on the surface soil with playing a major role in the surface settlement at the beginning of the excavation. The maximum surface settlement happened in the center position of pilot tunnel excavation. The maximum predicted value of the ground settlement was 24.75mm and the measured value was 25.51mm. The maximum predicted value of the bridge pier settlement was 5.11 mm and the measured value was 5.89mm. Both were basically the same. (2)The result showed that the PBA construction scheme for metro station and the in-site monitoring scheme were reasonable in design and the deformations of the ground surface and pier met the specification requirements. (3)This research result could provide the reference to construction and monitoring of the large-section metro station in the area with poor geological conditions.

Research conclusions: From the comparison of the numerical simulation results with the in-site monitored data, it is concluded: (1) For the shallow loess tunnel, it is proposed that it is unnecessary to use the arch anchor, and the sidewall anchor should be used according to the actual demand. (2)The grouting reinforcement can effectively control the strata subsidence caused by tunnel excavation for the shallow loess tunnel. (3)This research result can provide the reference the similar projects.

Research conclusions: (1) There is no obvious vertical velocity of the groundwater flow on both banks of the Qiantang River. (2)The horizontal velocities of phreatic water and artesian water are far less than 5m/d. (3)The groundwater's velocity and flow direction on both banks of the Qiantang River have a little influence on the construction of the river-crossing section of Line 2 of Hangzhou metro with freezing method.(4)In the case of no influence by nearby engineering construction (such as precipitation), the velocity of the groundwater in the Hangzhou area is generally slow with little influence on the construction of the metro engineering or municipal tunnel project with freezing method. So it is proposed it is unnecessary to do the determination of the velocity and flow direction of the groundwater during the engineering investigation in future.

Research conclusions: (1) From the analysis and comparison of the calculations results of the excavation processes obtained by using method, the track the full section method, the bench method and CRD method, it is concluded by using the CRD deformation and structure bearing load of the existing station can be effectively controlled.(2)On the base of the analysis of the numerical simulation results of the different reinforcement ranges for the surrounding strata around the new tunnels, it is proposed the grouting reinforcement should be conducted to the soil sandwich layer, the working face layer and the layer within 3.0m range on the left and right sides of the tunnel. (3)This result can provide the reference to the design and construction of the similar tunnel under-passing the existing subway.

Research conclusions: (1) The incoordination between the rail transit and urban spatial layout is affected by the following factors: unlike formulation department and term, different examination and approval department, diversity of investment main body, construction and management department, etc. Relevant departments should strengthen communication. Urban rail transit development should be coordinated with the urban spatial layout. (2)Accurate passenger flow forecast is important and difficult, thus the impact of rail transit on industry, business, science park and industrial zone along the rail transit line, even its influence on travel psychology and habit have to be considered. (3)From the research and analysis, this paper provides valuable advice on synchronous coordination of planning and construction between rail transit and urban spatial layout, which is conducive to strengthen control and management for the planning, investment, construction and management departments.

Research conclusions: (1) In the paper, a comprehensive analysis method with “analytic hierarchy process + expert investigation + fuzzy evaluation" is put forward for analysis and calculation of the risk of railway embankment engineering and the specific steps have been given. (2)It is suggested to class risk factors of railway embankment as slight degree, mild degree, moderate degree, severe degree and catastrophic degree and the corresponding treatment measures are put forward. (3)The calculation result shows the weight of seismic risk factor is maximum in the risk factors, therefore, the corresponding risk treatment measures shall be taken in the design of embankment in the seismic area.(4)The comprehensive analysis method with “analytic hierarchy process + expert investigation + fuzzy evaluation” is characterized by distinct levels，clear steps and quantitative analysis of risk, which can be used for identification and analysis of subgrade engineering risk of railway and highway.

Research conclusions: (1)According to the horizontal and vertical relative distances between the metro structure and the adjacent pipeline，the neighboring grade is divided into five levels(I-V); (2)To use the horizontal and vertical pipeline deformations as indicators to establish the safety control standard for the underground buried pipelines is more representative than other indicators; (3)With the deformation of the existing pipeline, usage, and its operation status taken into account, the safety risk of the tunnel-induced pipeline damage can be assessed into five different levels, namely Safe, Basic Safe, Dangerous, Basic Dangerous, and Very Dangerous. Corresponding prevention and protection measures are further proposed before and during the construction process for the adjacent pipelines according to their evaluated risk levels; (4) The proposed method is applied in one shaft foundation pit excavation project in Wuhan metro tunnel construction, and the results demonstrate the feasibility of the proposed method; (5)The research conclusions can be used in the metro tunnel construction fields by providing decision supports on the construction safety management.