Research conclusions：(1) From the monitored data in recent years, it can be seen that the long-term monitoring system for Qinghai-Tibet Railway has worked well. The monitored data are true and reliable. They can be as the basis for evaluation of the stability of engineering structure in permafrost area along Qinghai-Tibet Railway. (2) The long-term monitoring system has continuously monitored the subgrade in permafrost area for many years and found out the environment characteristics and settlement mechanism of the subgrade in permafrost area when the subgrade occurred big settlement and deformation. Based on them, the strengthened measures will be presented to better maintain the subgrade, improve the water thermal condition for the subgrade system, relax the drop of manual upper limit and slow down the settlement rate of the subgrade. (3) From the analysis of the monitored data on the bridge and the cross-section of culvert in permafrost area, it is believed the foundations of the bridges and culverts are entirely stable.

Research conclusions：With completions of Dezhou-Longkou Railway, Qingdao-Weihai Intercity Railway, Lancun-Yantai Electrified Railway and the second line of Dezhou-Longkou Railway and leading them into Yantai region in the near future or in future, the railway crossing pattern with two double -track main lines, one intercity railway and one double track feery railway will be formed in Yantai region. In the near future, the Longkou-Yantai Railway will be led into Fushan Station to remain Zhuji Block Postand drawn forth through the turnout 18 of Yantai-Daliang Feery Railway to connect with Yantai-Daliang Feery Railway and cross over the Lancun-Yantai railway in the middle part. After completion of the second track of Longkou-Yantai Railway in future, the Zhuji Sourth Railway Station will be built instead of Zhuji Block Post and it will have five main lines from the Longkou-Yantai Railway, the Yantai-daliang Ferry Railway and Lancun-Yantai Railway. Also the Longkou-Yantai Double-track Railway and Lancun-Yantai Single-track Railway will be led into the Zhuji Station.

Research conclusions：(1) The ecological trace and ecological capacity per capita of the Qiandongnan Miao & Dong Autonomous Prefecture in 2006 were 1.322 62 hm2 and 0.756 66 hm2 separately, and the ecological deficit per capita was 0.566 96 hm2, so the social and economic developments of the prefecture were unsustainable. (2) In order to construct the "green railway" in the Qiandongnan Miao & Dong Autonomous Prefecture and coordinate the railway construction with the environment protection, it is necessary to protect the forestry resource and water resource and make reasonable use of land resource.

Research conclusions：The wind blown sand was mainly concentrated in the space of lower than 3m in Gobi area and it was up to almost 87% of total sand volume. The density of wind-driving sand increased with the increase of wind velocity at the same height. The density of wind-blown sand decreased with the raise of height at the fixed wind velocity. The analysis result of sand particle size showed in the "100 kilometers wind area", the main movement form of wind blown sand in the space of lower than 3m was in leaping movement, and the main movement form of wind blown sand in the space of higher than 3m was in suspending movement.

Research conclusions：The Interval numbers attribute was used to evaluate the fuzziness and uncertainty of indexes. After standardizing decision-making matrix and separating it into mid-point matrix and radius matrix, linearly weighted aggregation and error transfer formula were employed to calculate the interval numbers of comprehensive evaluation value of all optional schemes. The possibility degree formula and ranking formula were used to rank and select optional schemes finally. The analysis of the case showed using this model could reduce the lost information for evaluation and improve the reliability of evaluation result. This model provides the other way for selection of soft soil treatment scheme.

Research conclusions：In order to study the feasibility of this method, a lot of tests were done to the tests ample, such as gradation test, compaction stroke test and in-site compacting test. In addition, the different compaction methods were used to the in-site compacting test for seeking a scientific and reasonable compaction technique. The tested result of technique showed this improvement method improved the grained gradation of filling material and enhanced the effective strength and compactness, which could meet the requirement of the code for the filling material. This method not only brought about obvious economic profits, but also brought out the huge social and environment-protective profits.

Research conclusions：The experiment done in the experimental section shows the compacting factor of soft rock filling material in red rock area shall be more than 0.93, and the tracks should be laid at least 6 months later after the embankment is filled. In this way, the post-construction settlement of top layer of the embankment of dig jet mixing pile composite foundation can meet requirement of the designed control standard, namely, the settlement is 15 cm and the settlement rate is 4 cm annually. The experiment also shows application of the dig jet mixing pile composite foundation with the distance between piles of 1.0 m and pile diameter of 50 cm and soft rock filling embankment is feasible, which is very significant to guiding the design and construction.

Research conclusions：From the analysis and discussion it is concluded the fibre light grid transducer can realize long-distance (50m), quasi-distributed, multi-spots and multi-parameter measurement with the high measurement accuracy. It can accurately measure the vertical displacement change of less than 0.1mm (relative to the reference base), and it is suitable for long-term monitoring with the good capacity of electromagnetic interference resistance and can satisfy the requirement of long-term monitoring the post-construction subsidence of subgrade of Zhengzhou-Xi'an Passenger Dedicated Line in moist loess area.

Research conclusions：The slope ecological protection is an important part of engineering, and protection works should follow the concept of "respecting nature and restoring natural". The style of slope ecological protection should reasonably arrange and suit the local conditions, such as the climate, hydrology, topography, soil quality and sources of material, etc. The slope ecological protection should be coordinated with the surrounding environment to maintain the balance of the ecological environment and beautify the environment.

Research conclusions：The analyses are made for the space stress-distribution and spatial variation of the longitudinal normal stress and transverse compressive stresson the roof and the shear stresson the sternum of large-span V-shaped continuous rigid frame arch composite structure bridge and their change regulations during the whole construction process. From the analyses the following conclusions are drawn: Firstly, the longitudinal normal stress on the roof of main girder is distributed along the transverse direction with unevenness, and the shear lag effects of the stress are obvious, which is different from the predicted results with elementary beam theory. Secondly, the transverse compressive stress of the main girder is not big and the uneven level of stress distribution on the roof is more than that on the floor.Thirdly, the shear stress distribution on the tri-web of single-box and double-booth section girder continuously changes and the shear stress on center web is slightly greater than that on the side web with good regulation. Lastly, during construction the envelope of longitudinal normal stress reflects the working condition with the maximum tensile stress and maximum compressive stress and this provides a theoretical basis for construction control.

Research conclusions：The Dashengguan Yangtze Rive Bridge is a tri-steel truss and six-span continuous arch bridge with two main arch spans in the middle and two side spans on the both ends. The general scheme of using double cantilevers to erect the steel truss of the middle main pier, using single cantilever to erect the steel truss of the two side main piers and conducting closure in the middle of the two main arches was adopted for the closure of the main arch of this bridge. Through the analysis of the monitoring computation and the study on the closure measures for the main arch of the steel truss arch bridge with three main trusses, the series of closure measures were taken for accurate closure of the two main arches of the bridge, such as using long circle hole, circle hole, dowel, pushing and pulling device and temperature difference.

Research conclusions：In design, the ratio between the stress and yield degree of vertical reinforcement should be controlled. The rebound value of 1.65 mm should be adopted when calculating the stress loss caused by anchor deformation and gap compression. The stress loss caused by installation error of anchor backer should be added and the rebound of 3.3 mm should be used. The stress loss caused by water thermalization of concrete and cement grout should be considered and the attention should be paid to improvement of the construction technique in construction. The error of incline angle should be controlled to make two flat and one straight and make the included angle within 1o when installing the anchor backer. The anchor torque of 1 200 N·m and 600 N·m with torque spanner should be used to φ32 reinforcement and φ25 reinforcement. The tension and super tension techniques should be used. The four groups of vertical reinforcements on the joint place of the front part and the rear part of the girder and the reinforcements on the rear part of the girder should be tensed at the same time.

Research conclusions：For construction of the post-tensioned presstressing box girder with traditional mud jacking technology, there are bubble and poisoned rain water in the mud to easily corrupt the pore space and prestressed reinforcement, resulting in reducing durability of the structure. In addition, the jacked mud probably is not compacted and saturated, resulting in pore space to reserve the hidden trouble in quality of the box girder. Application of vacuum auxiliary mud jacking technology can guarantee the compactness of pretressed duct after mud jacking and enhance the durability, security and service life of the structure.

Research conclusions：Based on studying a large number of data and TBM construction cases, the main engineering geological problems in the area where the tunnel passed through were analyzed. Based on the analysis of TBM construction experiences at home and abroad, it was decided to adopt the open-type TBM for construction of the tunnel and to adopt the composite lining structure made up of bolt-shotcrete support+cast concrete lining as support system of tunnel instead of segment lining. It played an important role in construction of tunnel and could be as the reference to the similar projects in the future.

Research conclusions：Based on the comparative result between of the criterion of permissible pressure wave in China and UIC criterion, the requirement of the sealing time for high running of train in tunnel of Beijing-Shanghai High-speed Railway was presented and the proposal was made that the train speed could be slower than 350 km/h when two trains met in tunnel.

Research conclusions：(1) The Norwegian Experience Curve Method is the simple stand the most easy and it is suitable for the primary determination at the early stage of geological survey while the construction period is pressed, but its result is conservative and needs to be economically verified at later stage. (2) The Water-resisting Rock Column Experience Formula can accurately determine the minimum security coping thickness and its result can be as the reference after the geological condition is well known. (3) The result obtained with numerical analysis is the most accurate, but the numerical analysis needs lots of certain conditions. Only when the external conditions, such as working condition, engineering geological condition and hydrogeologic condition, are determined can establish the model for returning the original construction condition, so its result can be as the reference to the final determination.

Research conclusions：The transient electromagnetic fields in tunnel appears propagation property of "water wave effect" other than "smoking ring effect" on ground. The low conductive body in tunnel obviously changes the time -domain property of eddy current to indicate the induction characteristic of abnormal body. The maximum of magnetic flux density occurs on the other side of centre due to the deflection of abnormal body from the centre line.

Research conclusions：The block stone debris can be consolidated by grouting and pipe-shed support. The time of drilling through an I20-beam is between 30 mins and 90 mins when using a driller with the torque of1 200 N·m to 2 000 N·m and rotational speed of 300 rpm to 500 rpm. The grouting under the local condition of water drainage can be controlled by using compound grouting material system of sulphoaluminate cement slurry and ordinary cement-soluble glass double slurry, following the grouting sequences of from down to up, from outside to inside and grouting every other hole, conducting sectional grouting with reasonable section length and combing a certain grouting number with a certain grouting pressure. After the block stone debris is improved by grouting, it can be used as an advanced φ76 mm pipe-shed support to ensure the construction security at burst port.

Research conclusions：Combined with the geological condition of surrounding rock of large section loess tunnel, the researches are done on the qualitative and quantitative indicators of construction process, subsidence, construction order, resource allocation, construction risks and construction costs of construction large section loess tunnel with CRD method, short bench 7-step method and twine side wall pilot tunnel method. In addition, the traditional excavation method is optimized in the construction or derand support method, and the advantages and disadvantages of the different construction methods are offered to provide the reference to the similar works.

Research conclusions：Using Leica cross-section measurement system to measure the clearance displacement change of the wall rock of tunnel is feasible, getting good results in judgments of the stability of wall rock and the support effect and also in finding the change of the wall rock. By using this system, the accuracy and reliability of the data can be improved and the manual error can be reduced, so the measured result from this system can be as scientific and reasonable basis for tunnel construction to ensure the construction quality and security and speed up the process of tunnel construction, and also can be as the important basis for optimizing the tunnel design.

Research conclusions：In this paper, it is proposed the BT undertaker substitutes for the owner to manage the supervision unit for further bringing into the better balance relations among the BT undertaker, owner and supervision unit, solving the problem of supervisions' deficiency and giving full play to the supervision. It is also proposed that the check-up system to the supervision unit by the BT undertaker, the communication system between the BT undertaker and supervision unit, the regular meeting system between BT undertaker and supervision unit, special examination system and inspiring system should be setup for improving the management system for supervision, giving full play to the supervision and enhancing the construction level of BT project.

Research conclusions：The government should strengthen the guidance in policy, and further implement and improve the qualification management system to give the qualification of integration of design and construction to the design and construction enterprises so as to push forward the general construction contract and enhance the market competition ability of Chinese construction enterprise. The Chinese construction enterprise should improve its internal management level, setup the standard system for the integration of design and construction, train the high-qualified talent of construction management, integrate the resources of design and construction, realize zero joint of design and construction, enhance the enterprises' management level and create the condition for implement of BT construction mode.

Research conclusions：Application of engineering measurement technology and information feedback technology can know the deformation situation of the monitored objects and therefore can make prediction and adjust the design and construction parameters in time for providing the accurate data to the metro construction and the reference to the similar works.

Research conclusions：To the construction section between two induced joints of one subway station in Shanghai, the temporal temperature values of subway station were collected from the test on the different construction phase. From the statistics of the tested temperature, it was concluded that concrete temperature was affected mainly by the temperature rise of hydration and atmospheric temperature in early concrete casting stage. In medium and later concrete casting stages, the temperature change trend of subway station was basically consistent with the atmospheric temperature, and the max. day-temperature drop of the top plate and the place around induced joints was more than that of other parts and the max. Day-temperature difference between outside and inside of top plate and bottom plate was more than that of the inside lining wall. Based on the analysis of the tested data, the proposals on the definition of temperature load and the in-site maintenance were made.

Research conclusions：This paper introduces the main design principle and technical standards for construction of Guangzhou-Qingyuan Intercity Rail Transit, compares and analyzes the three schemes in economy and technology from the fields of construction cost, construction difficulty, construction schedule, environment protection and coordination with the city planning, on the premise of meeting the track alignment, and offers the optimal scheme on the track alignment in city, namely, the scheme of track along Jingfu Road. This scheme can be as the reference to construction of the similar intercity rail transit.

Research conclusions：(1) The foundation of the originating tunnel portal was reinforced with φ1 000 triple tube high-pressure churning jet pile and the boring earth core for sampling with proportion of 0.5%-1% was conducted. The unconfined compression strength tested in the experiment was more than 0.8MPa and it could ensure the earth stability. (2) The portal originating guide-rail was installed in the originating tunnel portal to avoid the appearance of "knotow" of shield machine because the cutter head of the shield machine was hanging while the shield machine was originating. (3) The pressure of earth chamber was bigger than that of earth ahead. In this way, the "knotow" of the shield machine after the machine disengaging from the originating base and the over-big ground subsidence were avoided. (4) The safety of the originating process of shield was ensured though the check and calculation of the mechanics of the reaction shelf.

Research conclusions：The pains taken by the subcontractor to optimize design is in direct proportion to his coefficient of efficiency in knowledge and the profit distribution, but it is in inverse proportion to his coefficient of cost in knowledge and the proportion of designing fees in total project cost. The optimal distribution proportion of the whole projects' profit given to the subcontractor is in direct proportion to his coefficient of efficiency in knowledge, but it is in inverse proportion to his coefficient of cost in knowledge and general-contractors' coefficient of efficiency in knowledge.

Research conclusions：On the premise of ensuring the construction quality, safety and schedule , the construction scheme should be compared and optimized, the construction resource should be put in enough and the construction cost should be controlled to the minimum so as to optimize the general construction cost. Meanwhile, the particular countermeasures for the cost control should be taken according to the degree of the controllability of all cost elements of passenger dedicated line.