Research conclusions :(1) The difficult problems can be summed up as contradiction of disturbance with resolution ratio, contradiction of difference of physical properties with resolution ratio and contradiction of depth of exploration with resolution ratio. (2) Due to restriction of the difficult problems, it is notable especially that defection of the application effect on geophysical exploration. (3) If the difficult problems are solved or partly solved, the ability and precision of geophysical exploration will be greatly enhanced in railway engineering geological investigation, and it will be tremendous development on geophysical exploration technology.

Research conclusions ： (I) The result of sand particle size analysis shows that the mostly segment is less than 0. 25 mm in sand drift movement. (2) The different characteristics of sand — drift have been discovered between Xinjiang Gobi and Qinghai — Tibet Plateau. The wind speed causing erosion is about 11.0 ~ 20. 0 m/s in Xinjiang Gobi area, which is much larger than 7.0 m/s in the Qinghai — Tibet Plateau. (3) The laws of wind carrying sediment changes with height are described by power function，and the wind carrying sediment is decreased with height increasing. (4) Sand transport capacity attains to almost 90% of total capacity within 0. 5 meters in Qinghai - Tibet Plateau, but it is only 76% in Xinjiang Gobi area. (5) The research results can provide some references for the design and the construction of sand disaster protection engineering in the similar surroundings.

Research conclusions :(1) The different angle mountain shadow map by using DEM from lidar can accurately express the micro landform，and be advantageous to distinguish of geological disasters. (2) The boundary of slope, collapse and ground subsidence can be determined by means of lidar gradient image and DOM. (3) The slope deformation and ground subsidence can be dynamically monitored by means of lidar data of different periods. (4) The technique is effective for the unfavorable geological survey and monitoring of geological survey of railway and highway engineering, it has the characteristics of real — time, dynamic and initiative, which overcomes the defects of the traditional manual

Research conclusions ： It is concluded from the study that :(1) According to the test results of data analysis，due to the unbonded segments are arranged alternately at the free section on the new structure of delivery controlled anchor, peak values of anchor stress appear alternately along the free section during the loading process，and the stress distribution is relatively unifoml，which takes full use of the self-anchoring effects of the free section，SO the mechanical behavior of the anchor is well improved．(2)Viewing from the displacement of two different anchors，it Call be seen that the displacements of delivery controlled anchor is smaller than that of fully grouted anchor，and the slope deformation Call be restricted much better，which reflects the superiority of delivery controlled anchor．(3)The research results Call provide guidance and reference to the efficient use of anchor free section．

Research conclusions ： It was concluded that ： ( 1 ) It was the direct reasons causing " soil arching effect" in the embankment fill of the big difference between the stiffness of piles and the stiffness of soils, and the soil arching effect mainly depended on the differential stiffness. (2) For this kind of composite foundation, the settlement model included the equal - settlement zone in the embankment，the soil arching effect zone in the embankment，the negative friction impact zone, the positive friction impact zone and the equal - settlement zone in the substratum under the bottom of piles. The stiffness of the cushion had a main impact on the settlement difference between piles and soils. (3) For this kind of composite foundation, the average earth pressure on the top of CFG piles was 196 times bigger than the average one on the soil - area between piles，and that on the top of MIP piles was 22 times bigger than that on the soil - area between piles. The ground bearing capacity was obviously improved by MIP piles. (4) By this kind of composite foundation combined with preloading method for improving deep soft soil subgrade，96％of the total settlement was eliminated，and the settlement of post-construction was around 2．0 mill．Therefore， it met the requirements of stability during the operation of high-speed railway．(5)The research results can provide a good guidance for the improvement of deep soft soil roadbed in high-speed railway and highway．

Research conclusions :(1) Only grouting karst cave can control the tilt of pill foundation well，but it can not control the settlement of pile foundation effectively. (2) Only grouting the soil layer at pile tip can control the settlement of pile foundation effectively, but it can not control the tilt of pill foundation well. (3) Grouting both karst cave and the soil layer at pile tip not only can control the tilt of pill foundation well，but also can control the settlement of pile foundation effectively, as the result it is a better grouting reinforcement scheme. (4) The above conclusions can provide reference for the engineering of pile foundation grouting reinforcement in karst area.

Research conclusions :(1) The reliability of the traditional retaining structure design by using the total safety coefficient method is unknown, the effects of the variable uncertainty is not considered, some potential safety risks exist. (2) The research approach to study the limit state design method of retaining structure is to establish a limit state equation, analyze reliability index and determine the partial coefficient of design expression. ( 3 ) Determine the target reliability index and the partial coefficient in limit state design expression according to the different condition. (4) In this paper, the retaining structure limit state design method based on the probability theory can be directly used in the design of railway subgrade retaining structure.

Research conclusions :(1) The theoretical analysis and practical calculation results show that the safety coefficient or partial coefficient of retaining structure and reliability index are positive correlation. (2) The reliability index is closely related to the retaining structure limit state, corresponding to different status and safety forecast, the reliability index of the different classification should be adopted. (3) Based on viewpoint of system engineering, the reliability of retaining structure is maintained in the same level, each partial coefficient calculated in retaining structure design should be adjusted according to the analytical result of reliability index. (4) Reliability index classification of retaining structure in this paper and the viewpoint of partial coefficient adjustment based on same reliability requirement can be directly used to guide the design of the retaining structure.

Research conclusions :(1) The earth pressure is the key variable influencing the function calculation of retaining structure. (2) The uncertainty of comprehensive internal friction angle and uncertainty of computing model are the main source of uncertainty of earth pressure calculation. (3 ) The earth pressure calculation method has great influence on reliability index, and it is very important to correctly choose calculation model, which is the key to the reliability index calculation. (4) The earth pressure calculation based on the theory of probability is worth further study. (5) The research conclusions can be used for reference to the engineering designers and researchers.

Research conclusions :(1) Based on adjacent chord azimuth changes，the method of approximate segmentation can handle different curve radius measured data, and the result meets the requirement of fitting and iterating calculation.(2)By contrast of the segmentation results between measured data and design data，the method of plane accurate segmentation can achieve high segmentation accuracy.(3)By contrast of the segmentation results between measured data and design data, the method of vertical linear accurate segmentation is correct and the high accuracy can be achieved. (4) The research achievement can be applied in measured linear calculation，and has the reference value for linear adjustment in existing railway.

Research conclusions ： (1) The main reasons for the four - comer seams of CRTS - I ballastless track slab are the buckling deformation caused by the temperature difference between the board and the bottom and the Hanging Empty phenomenon between lower and higher tracks among adjacent slabs after track — laying. (2) The night or the season of least temperature difference between day and night would be better to do mortar pouring, and the best time is between 21:00 and 6 :30. Also delicate adjustment, effective clamping force and full mortar pouring are necessary. (3 ) It is also necessary to improve the adjustment accuracy of the slabs, especially to maximize to eliminate the height difference of adjacent tracks. (4) This study is very useful to reduce the seams of CRTSI,II,IH ballastless track slabs four comers.

Research conclusions ： The deflection of large — span prestressed concrete continuous girder bridges is long — term growth，and its growth rate is uncertain. The mid — span deflection increases with the span length，the growth rate has a close relationship with the span length and prestress loss degree, and the prestress loss effect is more obvious when bridge span length is greater. The prestress loss of top deck has more effect on mid — span deflection than that of bottom slab. The creep and shrinkage of concrete and the prestress loss caused by these are the main reason of mid — span deflection large — span prestressed concrete continuous girder bridges. This research results can be applied to optimization design and construction for large — span prestressed concrete continuous girder bridges.

Research conclusions ： Static model used in this article can simulate the construction site more accurately，dynamic calculation can simulate the acceleration and load reduction of reinforced system, and the vibration and resonance phenomenon can be reflected. Calculation and evaluation of railway reinforced system should be held under static and dynamic calculation. The results should be evaluated under advised standards listed in this article, then the conclusion can be more reliable. The research conclusions in this article can be applied to design and evaluation of railway reinforced system.

Research conclusions ： When the main structure and gravity center position of the crane are confirmed, the bogie wheelbase can be adjusted to improve its echo performance. If the product design cycle is short, first design the whole machine structure, finally adjust the parameters of the crane to improve its echo performance. If the product design cycle is long, constantly optimize the crane design, use the method which adjusting the weight and gravity center location of the crane and crane bogie wheelbase and axle load, to get ideal crane echo performance.

Research conclusions:(1)PC cluster system has high flexibility，and can be expanded in accordance with needs. (2)For the problem which a single computer can handle，PC cluster system is not dominant. But，for larger three- dimensional numerical simulation of geotechnical engineering，PC cluster system has advantages in realizability and operational speed，greatly improving working efficiency.(3)Realization of numerical simulation of Jiaheyuan underground engineering，not only guides the construction of this engineering，but also verifies that PC cluster system has the advantage in large scale three-dimensional numerical simulation. (4)PC cluster systems based on the personal computers make the complex numerical simulation of underground engineering achieve. It provides a convenient and cheap solution for underground engineers.

Research conclusions:Compared to grey prediction，smoothing prediction，ARMA prediction，the prediction accuracy of optimal combination prediction of tunnel deformation based on the number of gray relational degree OWGA operators is higher with minimum error. Its forecasting result is not only reasonable and effective，but also is optimal. This research can be applied to tunnel safety monitoring and deformation prediction field.

Research conclusions:(1)Combined with acoustic emission monitoring technology，we can get two indexes more accurately than conventional experiment. (2)According to rock properties and surrounding rock stress，we increase the evaluation indicator of deformation brittleness coefficient method. It showed that the results from the comprehensive evaluation method of fuzzy mathematical are more in line with the actual situation of the rock burst of tunnel compared with the single index evaluation.(3)The research result provides a feasible method to predict rockburst and it is significant to prevent and control of rockburst in advance for similar engineering.

Research conclusions ; The research proves that the locomotive load current distribution ratio is the same to the current distribution ration under short-circuit condition. So it is workable to make research with locomotive load current value instead of short-circuit parameters. The verified parameters calculated with locomotive load apply to the protective value of the failure distance and locate the actual failure point. Establish the T-R short-circuit ratio curve graph of each section of the whole line by using a large amount of data，and then confirm the failure point location by seeking table method. This technology could be applied to up and down all-paralleling AT feeding systems distance measurement accuracy verification and formulas of newly built and operational railway passenger dedicated line to verify parameters.

Research conclusions:(1)Track fitting spectrum using track irregularity spectrum model from China Academy of Railway Sciences and Levenberg-Marquardt method characterizes the original spectral characteristics well. (2)Subway track irregularity spectrum is with spectrum signature of broadband and narrowband random wave and some harmonic with complex periodic，different subway lines are with different spectrum signatures.(3)The condition of profile and align irregularity maintains well.(4)The research results could be used in track structure design and track maintenance.

Research conclusions: Technical solutions to the problem of high pressure aquifer in the construction of Hangzhou subway are proposed as below:(1)The brine freezing method in conjunction with the mode of tunneling shield reaching the shaft underwater is used to avoid the risk of quicksand and water gushing. (2)The preventive measures against water gushing based on the structure optimization of shield are set, including two inverted one-way restrictors installed in the conveyer and two rings of wire brush seal appended a ring of steel plate brush seal; and the EPDM rubber gasket with water pressure resistance of 0.9MPa is determined to use as waterproof measures of segment joint.(3)The connected aisle under the river is constructed by the subsurface excavation technology and reinforced by a new freezing method，the frost heave and thaw collapse of which is controlled by the deformation of tunnel linings.(4)Combined with the foundation engineering of Jiangling Road station，a complex pressure reduction and dewatering technology is developed， which is to form a complete shut-off waterproof curtain by overlapping a grouting curtain with a certain depth beneath the toe of diaphragm wall. (5)The technical solutions to the problem of high pressure aquifer encountered in the subway construction mentioned in this paper guarantee the successful engineering implementation of Hangzhou Metro Line 1， which can provide valuable experience to the subsequent construction of Hangzhou subway.