Research conclusions: Based on the concrete engineering project，in this paper，a systematic analysis is made of and a comparative research is done on the supporting effects of bolt—grouting support and bolt-shotcrete support under condition of fractured soft surrounding rocks by means of numerical method．The research shows that for fracture soft surrounding rock，the bolting—grouting combined support increases the self supporting capacity of surrounding rock and the radial supposing pressure on the tunnel circumference by increasing the strength of surrounding rock and anchoring force of bolt，and it is more efficient than bolt—shotcrete support in terms of confining the deformation of surrounding rock，controlling the expansion of plastic zone，increasing anchoring force，decreasing the stress on steel arch and shotcrete，improving initial support stability．Therefore，the bolt—grouting support is especially used for supporting the fractured soft surrounding rock．

Research conclusions: For the cutting slope in permafrost region with the high ice content，the destabilization of thaw slope is a typical disease and the reason for it is there is the water on freezing layer and slope absorbs heat to cause the high—ice—content frozen earth thawing．The treatment principle for it is to strengthen dredging water in the freezing layer of the upper slope and draining the water in cutting of roadbed while emphasizing on the thermal protection and draining water in the surface．For the cutting slope in permafrost region with low ice content，the damage of shotcrete protective covering of rock slope is a typical disease and it is related to the water gathering on the freezing layer toward slope．The treatment principles for it is to strengthen water drainage under the concrete layer of slope，remove the damaged concrete layer that brings harm to the traffic safety，and build the light slope protection structures，like frame anchor that does not hold the water back when the concrete layer is broken．In principle，sealing the cutting slope in permafrost region is inadvisable．

Research conclusions: The maximum dry density can be decided by the vibrating compaction technique．The construction machinery combination is advised．Namely，the bulldozer(not less than 140 horsepower)，the back and Forth driving road roller(1 8—25 t)，and the grader should be used together．The thickness of the carrel—built layer is controlled at 50—80 cm．and it is guaranteed at 40—60 cm，no more than 60 cm after compaction．The concrete process includes the 2—3 times rolling by bulldozer，the fine levelling by grader，the 1 time of stationary compaction by roller，the 2—3 times vibrating compaction by roller，the bulldozer stationary compaction by the roller．

Research conclusions:The support stiffness for subgrade surface is an important parameter for analysis of ballastless track structures and also the key factor for matching the longitudinal stiffness of the foundation under ballastless track．It can reflect the structural support performance of the top surface of roadbed to the track structure surface and it is also as the requested index of the track structure for the subgrade structure．The support stiffness for subgrade suI'face can be controlled by optimal design of the vertical stiffness of the subgrade bedded system．The longitudinal stiffness of track can be adjusted and matching the stiffness of the subgrade with the other structure can be realized by optimal design of the vertical stiffness of the subgrades with different sections．The support stiffness for subgrade surface can be tested with loading plate and the area ofloading plate should be 1．0×1．0 m2 to 1．5×1．5 m2．

Research conclusions: From the qualitative and quantitative analyses it is known the weight values of all sub—items are variable，and the distribution of the weight values are offered through the study．In the course of construction，the rational construction scheme should be chosen，the attention should be paid to the fastening management，and the measurement reliability of track should be ensured，the construction technology should be taken the control sector。The construction procedure and standard should be implemented to every job，and the advanced construction machinery should be used to avoid the the error transfer and accumulation and guarantee the the construction quality of ballastless track．

Research conclusions: From five aspects of comfortableness，stress，vibration，deformation，and matching components stiffness，the criterions for determining the reasonable stiffness of the turnout were proposed．The method for determining the track stiffness was also established by using the vehicle—turnout space coupling dynamic analysis and track deformation analysis． With this，the research Was done on reasonable stiffness of ballastless track turnout of 250 km／h passenger dedicated line．The research results showed that stiffness of 36～44 kN／mm to the fastening．The stiffness of 290. 330 kN／mm to the rubber pads under rail，and the stiffness of 40—50 kN／mm to the rubber pads under tie plate were reasonable．

Research conclusions: According to the comfortable requirement，the matching relationship between radius of curves behind the tumouts and superelevation under the conditions of different train running speeds，and the values of transit curves radius under different radius of curves behind the turnouts are given out．The study on optimizing the length of inserted section in curves behind the turnout and length of transition curves shows the length of the folded line between curves behind the turnouts should avoid taking the value of the sum of the fix distance and peak value attenuation distance in the first cycle of vehicle vibration on folded line．To the curves with radius of 1 200 m，the folded line length of 30m is unsuitable．When the length of transition curves behind turnouts is more than 50 m，the comfortableness is not improved obviously．

Research conclusions: The results of experiments and analysis showed that high quality cladding coating with the thickness of about 1 mm can be obtained under the conditions of laser power being 4 200 watts，scanning speed being 300 mm／min and powder feeding velocity being 1 8 s／min etc．The coating had a higher hardness value of HV780 than that of the SUbstrate material，but there existed a hardness knee point between the coating and the substrate．The laser cladding coating did not appear cracks under the static load of 453 kN．The organsof the Fe -based coating weremainly composed of C-Fe, Cr0. 19Fe0. 7Ni0. 11, NiCrFe and FeCr etc. The martensite structure was formed in the fusion area adjacent to the substrate because of the rapid heating and rapid cooling.

Research conclusions: Using graded gravel to reinforce the transition section，the total amount of settlement is not large with a regular pattern．The largest amount of settlement of the transition section OCCUrs at the area where is 10—20 m away from structures，and the amount of settlement is proportional to filling height，and the settlement velocity is in the positive correlation with filling time．With the”heaped loading and pre—pressing”after construction．the overall settlement tends to steady state．

Research conclusions: The settlement of the pier and abutment of Yunlianghe Bridge of Harbin—Dalian Passenger dedicated Line becomes stable．With the metabolic GM(1，1)model of gray system，the prediction model for accumulated settlement can be established easily because of needing a little measured data．Although there is a certain gap between the predicted data and the measured data，but the prediction model can reflect the change trend of the settlement at the observation point and the approximate settlement volume at t}le observation point can be known before the next observation，80 the prediction model is significant in prediction of the settlement．In addition，the prediction model has a high accuracy and it can be used for prediction of the accumulated settlement．

Research conclusions: Regarding train and bridge as one composite system，by means of the principle of total potential energy with stationary value in elastic system dynamics and the”set—in—fight—position”rule for structural matrices. the vibration equations of vehicle—bridge time varying system are established．This method is more convenient than the finite elements．The vibration responses of a simply—supported truss bridge are calculated when DF4 locomotive hauling 25 C62 freight wagons and DFl 1 locomotive hauling 1 8 passenger coaches to pass this bridge at the different speeds．It Can be seen from the analysis that the traffic safety is guaranteed and the comfortableness and stability of train reach at the standards．It shows that the bridge has sufficient lateral and vertical stiffness．

Research conclusions: The result of experimental research show the performance parameters of the material in the welded defect area aye variant，the parameters should be decided separately to the master material，toe zone and weld material rather than deciding one parameter for all of them．In this way，the results of lean calculation and analysis with finite element software can be more close to the actual loading situation．

Research conclusions: The stratum reinforcement scheme and the sleeve—valve—pine technology presented in this research could solve the problem that the core of the deep sleeve--valve—pipe was stuck or fallen when grouting and the problem that the TBM Was probably packaged when grouting in front of TBM．With improving the stratum by grouting，TBM could work normally．

Research conclusions: There are many factors that can cause the cracks．The shrinkage crack is the preliminary causes for the through crack in the secondary lining of tunnel．The temperature drop can cause the crack to develop into larger one．And the self—gravity，the construction disturbance or the uneven settlement under rock mass pressures can cause the crack continuous developing．The study shows the capacit)r of crack—resistance of concrete can be improved if the concrete is mixed with external material and high—efficient water—reduction agent．The secondary lining should be kept a certain distance from the excavated section to reduce the disturbance of excavation blast to the concrete of secondary lining．The tunnel portal should be enclosed for insulation．The joint—to-joint construction should be conducted to the concrete converted arch and the secondary lining for prevention of the harm of crack deformation caused by the converted arch construction to the secondary lining．

Research conclusions: Through the study，the lumped parameter interval algorithm，fault network decomposing interval algorithm and distributed parameter interval algorithm were deduced by using interval analysis method．The PSCAD simulation analysis Was made for the actual transmission line model to verify the feasibility of interval location method．In order to further test its practicability in engineering，the field simulated tests were done with the three algorithms for railway continuous power transmission line from Kaili to Fuquan．The tested results fully met the requirements of precision and rapidity for fault location．Both the theoretical calculation and factual tests had shown that the using Interval algorithm could effectively solve the problem of fault location railway continuous power transmission line．

Research conclusions: Through the study，a noble direct torque control system based on low—dimension fuzzy control theory is proposed to decrease the torque ripple．In this system，the torque and magnetism ate used as two inputs to form the fuzzy control and the control functions are used as fuzzy output．The output of fuzzy controller is used as the input of vector table and the suitable voltage in each control period can be determined．The simulation results show that the torque ripple is decreased dramatically．

Research conclusions: From the concrete construction example and the field data about the construction process it is concluded the control of concrete matching ratio，inspection of material quality and control of insulation after construction are the key sectors to prevent the crack of mass concrete，and the ratio of reinforcement，construction scheme and adding agent are also the important sectors to prevent the crack of mass concrete．Therefore，the construction scheme should be implemented strictly in construction and the responsibility sense of the constructors should be strengthened to ensure there is no error in every key link．

Research conclusions: According to the real engineering conditions of Nanjing metro，the three—dimensional finite element software ADINA was used for simulation analysis and the simulation result of the pumping settlement of this engineering project was obtained．The simulation result basically tallied with the results of the field pumping and the indoor experiment．So application of the numerical simulation can provide the scientific numerical data for prediction of pumping settlement．

Research conclusions: Compared with the structure of no conversion layer，the intemal force of the structure member above the conversion layer changes a little while the internal force of the every flayer below the conversion layer increase much．For the structures of conversion layers at different heights。the internal force of the structure member below the conversion layer changes a litde while the internal force of the structure member above the conversion layer increase much．Under horizontal load，the deformation curve on the structure above conversion layer is shearing deformation mainly and the the deformation curve on the structure below the conversion layer is bending deformation mainly．The Conversion layer is the turning point between above and below deformation Curves．With no conversion layer，the max．Value appears on the low part of the structure．The top displacement increases with raising height of the conversion layer．The conversion layer is the place with small displacement between layers．Therefore，if the design is reasonable，the arched conversion layer Can have a perfect seismic performance．

Research conclusions: The impact of the appreciation of RMB on undertaking the international engineering projects lies in the project income and project expenditure．As there are different ways of valuation，the appreciation of the RMB has much greater impact on lump—sum valuation after the completion of a project than on periodic valuation．Besides，in terms of project cost，the appreciation mainly affects mechanical equipment cost and labor cost rather than material cost．In order to reduce or avoid the loss brought about by the appreciation，the construction enterprise Can take some measures for avoiding risk，such as accepting and valuating works by month，requiring advance payment，in—time currency swap，fixing exchange rate and trading resources with projects．

Research conclusions: The professionalization of the project manager is the the important way to strengthen construction of the project manager，and the development direction is to take construction of the team as the target，take the qualification management as the basis，separate the qualification with employment，establish the inspiring systems，such as subsidizing with the position，achievement examination，commendation and award and prior rising in rank，and strengthen the team training．The professinalization of the project manager can provide the operable model for standardized management of the project manager and make it possible to copy the the project manager in the enterprise．The construction of professinalization of the project manager should be conducted gradually for a long—terra period．It needs a continuous exploration，improvement and innovation．In this way，the management system and operation mode for the project manager with the enterprise characteristics can be formed and the talent basis for the sustainable development of the enterprise can be established．

Research conclusions: From the analysis it is believed the Chinese enterprise should enlarge the investment in Mongolian mineral resources．In addition，the measures for avoiding the investment risk should be taken by the Chinese enterprise，including learning the Mongolian laws，doing the research on the project feasibility，inspection of the mining right and relative documents and strengthening the communications with the governments at all levels．It is believed through taking these measures，a period of healthy and rapid development will come for the Chinese enterprise to invest in the Mongolian mineral resources．