Research conclusions: The theoretical analysis and relevant experiments proved that using the adjustment method of absolute survey with high accuracy ETS could meet the accuracy requirements of within ± 2 mm for the horizontal irregularity adjustment of the ballastless track of high － speed railway．

Research conclusions: ( 1) Deformation failure mode of the slope is dependent on the inner structure of slope，the physic － mechanical properties and outsider factors; ( 2) Studies on mechanism of the slope deformation failure and on slope deformation failure and stability at every different evolution stage are necessary for proposing proper slope treatment measures in accordance with its development stage; ( 3) Comprehensive treatment proposition，which combines several propositions such as earthwork reliving，materials replacement，anchorage，retaining and drainage etc． ，could be taken into consideration during the treatment．

Research conclusions: According to the characteristics of disposal engineering of the foundation of the blowing sand reclaimation，a 3 － D numerical model was established to study the settlement caused by the dynamic compaction． Its results was compared with the data of some actual projects for treating the sand － soil with the dynamic compaction method． By loading with compaction hammer，the volume of void was decreased and the density of the soil was increased，obtaining good treatment result． This method was available for treating the foundation of blowing sand reclaimation in the coastal area． The most reasonable dynamic compaction parameters were got by comparing and analyzing the numerical simulation research and the actual project，and it could provide the reference to the similar works．

Research conclusions: ( 1) During the Early Operation，the subgrade engineering in Permafrost Region Railway，we found that the overall deformation has been on the decline and subgrade deformation has stabilized． ( 2) The upper limits of permafrost in most subgrade sections have increased，their statuses have stabilized and the cold reserves of bases have increased． The increase in upper limits is a result of the decrease in soil temperature． ( 3 ) The status of subgrade engineering has changed because the changes in geothermal field have altered the places and soil depths of deformations． At the same time，the asymmetry field causes deformation differences and deduces cracks． Hydrothermal changes will result in cracks． ( 4) Asymmetry thermotics in subgrade structure will soften the asymmetry of upper limits，thus reduce the difference of horizontal deformations and prevent cracks．

Research conclusions: The saturations of unsaturated silty clay and floury soil along the Qingdao － Jinan Railway are between 46% ～ 80% ． The embankment settlement during construction period can be above 75 percent of the total settlement and about 90 percent of the total settlement after 3 to 5 months． The stress － strain curve and the strain － time curve tally with the hyperbolic model，and hyperbolic method is recommended to predict the settlement of the subgrade． It is unnecessary to treat the unsaturated soil subgrade of the ballast track of passenger dedicated line． It is necessary to conduct the treatment to the shallowness from 5 m to 8 m of the subgrade of ballastless track of passenger dedicated line． The treating depth should increase for the high filling and transition sections of the ballastless track of passenger dedicated line．

Research conclusions: By adopting the geological mapping and geophysical prospecting first and then conducting the specifically disposing drilling，in － situ tests and various laboratory tests，the investigation cost can be effectively reduced and the survey precision can be met． The in － site survey shows adopting various comprehensive engineering geological investigation is available for the Ethiopian Railway Project．

Research conclusions: By establishing the finite element model for the prestress concrete beam and the cast － in － place falsework，the analysis and calculation are made for the changes of the load bearing of the cast － in － place falsework under conditions of the concrete casting，designed strength，tensile vertical prestress and tensile lateral prestress in each construction stage． The calculation results show when the vertical and lateral prestress is in tensile state，the the concretebeam will deform to cause transmission of the load on the cast － in － place falsework into the two sides of the falsework． The more tensile prestress there is，the more obvious the load redistribution sign is． The load redistribution will produce the big negative impact on the local structure of the falsework．

Research conclusions: In this paper，the analysis and discussion were made on the commonly － used calculation methods for the impulsive force of falling stone． The calculation of the impulsive force of falling stone was made for the additional hangar tunnel at the tunnel portal of Xiangfan － Chongqing Railway with the subgrade technical manuals method，tunnel technical manuals method，Labiouse method，Kawahara method and Yangqixin method． It was shown that the calculation results obtained by these five methods were almost the same in magnitude． The results obtained by the subgrade technical manuals method and tunnel technical manuals method were a little bigger than the others．However，on consideration of that these two methods had been applied and verified in a large number projects，it was proposed to use the calculation results obtained by these two methods as the design load of the additional hangar tunnel and based on them to make the design．

Research conclusions: It can be seen from the study that the ground penetrating radar wave reflected by the rock around tunnel lining has a larger amplitude and stronger signal disorderly than the wave reflected by tunnel lining． The waveform reflected by the steel structure in tunnel lining looks like hyperbolic，but the amplitude of the hyperbolic of the reinforced bar is relatively narrow，and the hyperbolic of the of the steel arch frame extends much vertically with small lateral extension． The waveform reflected by the lining cave or surrounding rock cave has characteristics of the confused phase axis of the reflected wave with repeated and stronger reflections and low frequency．

Research conclusions: Taking Jiubao Tunnel project on Zhang Jiakou － Ji Ning Railway as an example，this paper studies on safe construction techniques for tunnel passing through F3 fractured fault zone and water － rich zone． The rules of “ depressurization，dewatering ，advance support，safety guarantee”are put forward． It presents that the key point of hazard prevention and safe construction is to solve the problems of high pressure water．

Research conclusions: In the process of the excavation of the foundation，the deformation of guard pile increased with the increase of the excavation depth． The maximum deformation of the guard pile appeared in the middle － low part of the excavation depth． The place in where the maximum deformation appeared shifted down with the increase of the excavation depth． The supporting axial force increased largely at the beginning，but it varied a little with the excavation of the foundation pit and installation of the next support． The tested axial force of the various supports during construction was to the 70% of the design value．

Research conclusions: Through the study of the problem，such conclusions are obtained: ( 1 ) To control the the incisions pressure fluctuations in the value of less than 0． 1 bar; ( 2) Difference of the slurry flow and the promoting speed should be match，at the same time ，to control the amount of overbreak; ( 3) The thrust should be in the range of 9 500 ～ 100 000 kN; Shield driving speed is controlled at 10 ～ 20 mm / min． Cutter speed in control of 1． 0 ～ 1． 2 rpm / min is appropriate，and at the same time to control the cutter torque between the range of 0． 9 ～ 1． 2 MN?m．

Research conclusions: From the comparison and analysis of the cantilever － type retaining structure and the slope platform submerged retaining works in areas of the structure design，mechanical analysis，project investment and landscape requirements，it is concluded compared with the cantilever － type retaining structure，using the slope platform submerged retaining works can save the project investment by 50% and the effect of greening the slope can be achieved．

Research conclusions: To build the strategic management and control system for central enterprise is crucial to improving the enterprise ability in the strategic management and control and reducing the enterprise risk． According to the strategic management and control characteristics of the enterprise，the central enterprises should master the scientific rules，follow the systemic design principles and comprehensively consider the relationships among the every factor， various levels and various bodies to set up a set of proper strategic management and control systems for enterprises development． The central enterprises should carry out the loop execution according to PDCA，and by the feedback and effect evaluation，the strategic management and control can be improved continuously．

Research conclusions: ( 1) Subsections focus on the designing and overall planning of the project，coordinate the whole designing、construction and purchase，take charge of the external accountancy and settlements in the whole project，put the progress and invoice check under centralized management etc． ( 2 ) Flat management simplifies the management hierarchy and makes it closer to the front － line，which helps improve the efficiency and reduce costs． ( 3) Analyze and measure the cost － benefit relationship of the machinery equipment for construction seriously． Make a thorough comparison of the performance － price ratio and after － sales service of the same equipment both at home and abroad for the final decision． ( 4) Enhance the skill training and all － around education of workers． Standardize field operations． Increase the proportion of local employees，which helps reduce costs on workers and promote the employment of the country to fulfill the community responsibility．

Research conclusions: Through researching the qualification management of engineering survey and design enterprises，according to the dependency level of enterprises on qualification and the role of the qualification in the enterprisebusiness，the analysis and review are made on the qualification management of the enterprise from three interconnectionfields of the history and current situation，the influence of the qualification system on the enterprise and the qualificationmanagement tactics． The countermeasures are presented for improving the qualification management of the enterprisefrom the fields of the enterprise development tactics，building talent system and integration of the enterprise resources inorder to promote and improve the qualification management of the enterprise and the enterprise development and makethe enterprise invincible in serious market competition．

Research conclusions: Facing the serious safety production situation，the construction enterprise should adhere to the outlooks of the scientific development and safety development，set up the concept of " zero accident" ，that is to say every safety accident can be prevented． In addition，the implement capacity of the enterprise should be strengthened，the organization security system for the safety production should be built and improved，the rules and systems for the safety production should be worked out， the check and control of the hidden danger of safety production should be strengthened，the education and training for the safety production should be improved，the supporting role of science and technology should be played in the safety production and the key and important links should be strictly controlled． At the same time，it is necessary for the country and the industry to improve the law and rule sytems，normalize the admittanceof construction market，the bidding flow and the working out financial estimate，optimize the project design，scientifically decide the construction period，normalize the construction supervision，reduces the local interference and correctly guide the supervision of the public opinion． The measures mentioned above are crucial to the safety production and scientific， safe and healthy development of the large － sized construction enterprise．

Research conclusions: Currently，the large － sized state － owned construction enterprise has two financing manners of bank loan and stock with the problem of insufficient applicable depth． It is suggested to apply them more deeply． Engarging the financing manners for large － sized state － owned enterprise includes three manners of the bond，leasing and trust． But some obstacles exist in spreading the application of these three manners． The joint efforts from the government，enterprise，and intermediate agencies are needed． In enlarging the financing manners for large － sized state － owned enterprise，it is necessary to pay more attention to the control of the financing risk and selection of financing manner in order to minimize the financing risk and financing cost and meet the enterprises＇ requirement of sustainable financing．英文关键词