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Zhu W.,Guangzhou Metro Corporation | Zhong C.,Guangzhou Mass Transit Engineering Consultant Co. | Huang W.,Guangzhou Mass Transit Engineering Consultant Co. | He T.,Guangzhou Mass Transit Engineering Consultant Co. | And 2 more authors.
Modern Tunnelling Technology | Year: 2017

As for the rock ground with large overburden and developed rock fisser water as well as the mixd ground with rich water and airtightness, the blow-out event often occurs due to a large shield load and quick wearing of cutting tools when conventional full earth pressure driving mode is adopted, which results in low efficiency and poor-quality simutaneous grouting. The definition of the "air pressure balance" mode and its advantages and disadvantages are presented based on practical experience with the Guangzhou Metro lines 1, 2, 3 and 13. Additionally, key techniques for "air pressure balance" driving mode are studied, secondary risks concerning this driving mode are analyzed and measures for prevention and countermeasures for emergencies are given in this paper. © 2017, Editorial Office of "Modern Tunnelling Technology". All right reserved.


Li B.,Xi'an University of Architecture and Technology | Huang W.,Xi'an University of Architecture and Technology | Li C.,China Railway First Group Co. | Dong K.,Xi'an University of Architecture and Technology
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2017

Based on strain equivalent theory and the micro-unit strength of steel fiber recycled brick aggregate concrete (SFRBC) obeying Weibull distribution, a statistical damage constitutive model for the SFRBC was established. To reflect the SFRBC compression of actual situation better, the influence on the model was analyzed by respectively introducing a correction coefficient of considering the residual strength and a damage threshold. Based on the analysis results of distributed parameter m, S0 on the model curves, the expression fiber factor considering the fiber content and distribution parameters was fitting. Then, a statistical damage stress-strain theory curve was established and compared with the test results. The results show that the corrected theory curve agrees well with the test curve, and with the increasing of steel fiber, the results of toughness of SFRBC enhancing and the macro-average intensity improving can be effectively reflected. According to the analysis result of the cumulative damage evolution process, the cumulative damage and the damage rate after the peak stress is effectively delayed. The strain hardening of the decline on the curves behaves obviously, and the toughness and ductility is varying degrees enhanced with the increase of the fiber contents. © 2017, Editorial Board of Journal of Huazhong University of Science and Technology. All right reserved.


Zhang Y.,China Railway First Group Co.
Modern Tunnelling Technology | Year: 2013

It is a key point for the security of deep foundation pit enclosure structure in the design of deep foundation pit support which guarantees the normal construction of foundation pit and prevents from soil mass movement inside and outside the pit in order to keep the normality of buildings, roads and pipelines nearby. Special attention was given to the soil mixing wall featuring good applicability, low construction cost and short construction period. Based on the construction practice, some discussions of the key techniques in the design and construction were made regarding the application of soil mixing wall with a large diameter to deep foundation pit in soft soil.


Cui K.,Central South University | Cui K.,China Railway First Group Ltd Company | Zhang M.,Central South University | Wang X.,Central South University
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

Based on the slip surface model of foundation damage used in the Meyerhof solution for the ultimate bearing capacity of deep foundation, the ultimate bearing capacity at the tip of a pile that is embedded in rock is deduced by applying the generalized nonlinear unified strength criterion and slip line principle for resolving the differential equation systems which govern the stress field. Then, the variation laws of end bearing capacity with sliding surface angle and embedment ratio are studied. The impacts of intermediate principal stress and overload factor are discussed in the analytical solution. Results show that the end bearing capacity decreases nonlinearly with the embedment ratio, but increases with respect to the intermediate stress parameter. And the bearing capacity factor increases with the overload coefficient hm when the embedment ratio n is smaller, but decreases while the embedment ratio is greater. The end bearing capacity defined by current pile design code is conservative according to the calculation results.


Gen J.-M.,China Railway First Group Ltd. | Qi Y.-Q.,China Railway First Group Ltd. | Dai C.-L.,China Railway First Group Ltd.
Journal of Railway Engineering Society | Year: 2013

Research purposes: The detailed introduction is given in this paper to the functions of the JGMZY 10 type multi-functional operation vehicle for tunnel. The vehicle's functions are as follows: The folding arm crane can be used for installing the construction members and lifting the small parts in the limited space in tunnel and if the special fixture is used in stead of the hock, the arch can be lifted with mechanization. It provides the reference to the similar works. Research conclusions: The JGMZY 10 type multi-functional operation vehicle for tunnel has the following features: (1) Its structure is simple, its design is reasonable and its operation is easy. (2) The mechanizations of the installations of the arch and waterproof plate can be achieved by using the JGMZY 10 type multi-functional operation vehicle for tunnel and it meets the mechanized construction requirement by the Ministry of Railways. (3) Its application in construction of the Fajishan Tunnel shows the working efficiency can be much enhanced by using it.


Bai Y.-J.,China Railway First Group Co.
Journal of Railway Engineering Society | Year: 2013

Research purposes: Precise adjustment is an important process to guarantee smooth, high speed and reliable operations on high speed railway lines. This paper focuses on the research of key processes in static precise adjustment of CRTSIslab ballastless track in view of the engineering practices on several high speed lines to formulate engineering techniques for precise adjustment on line with elastic split fastenings. Research conclusions: The study of track precise adjustment processes and engineering practices have demonstrated: (1) The self-developed data simulation and analysis software on the principle of track adjustment data simulation and analysis serves to support track precise adjustment and improve work efficiency; (2) Such proposed working procedures in precise adjustment as "first track irregularity, then track level, first track alignment, then track guage" has reduced workload; (3) The proposal to use the same rail as the reference to adjust irregularities and alignment has protected the track from disturbance generated during precise adjustment, reduced repeated adjustments and improved its efficiency and quality; (4) The research conclusions are applicable to static precise adjustment on high speed lines and dedicated passenger lines with CRTSIslab ballastless track and elastic split fastenings.


Xiang Z.,Central South University | Yuan R.,China Railway First Group Co.
Advanced Materials Research | Year: 2012

studies were carried out to determine the principles of mechanical equipment coordination for large cross-section tunnel construction in combination with the tunnel construction practices within the sections under the charge of China Railway First Group Co., Ltd. On Wuhan-Guangzhou PDL and with a view to optimize the allocation of resources and improve the efficiency of large cross-section tunnel construction. Directed to different procedures such as excavation, support, waterproofing, drainage and lining, the mechanical equipment coordination and operation mode of large cross-section tunnels on the passenger dedicated line were established and the mechanized working faces were formed, which provide experience and reference for the large cross-section tunnel construction of passenger dedicated lines.


Wang X.,Xi'an University of Architecture and Technology | Shao Z.,Xi'an University of Architecture and Technology | Song L.,Xi'an University of Architecture and Technology | Song L.,China Railway First Group Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2016

Rocks possess viscosity property, which cannot be ignored. Deformation behaviors of rock-like materials display the characteristics of the rate-dependence, which manifest macroscopically non-equilibrium nonlinear effect of elastic aftereffect, creep, and relaxation. Based on the classic Preisach-Mayergoyz space theoretical model, anelastic mesoscopic unit(AMU) possessing time-dependent peculiarity is introduced to obtain the modified PM theoretical model. By adopting the modified PM space model, characteristic of stress-strain curves with different loading rates and the non-equilibrium effect are studied in detail. Finally, experimental approach to obtain the deformation-time curve of the AMU and reconfiguration of the modified PM space is proposed. Results obtained in this paper indicate that, the area of stress-strain hysteresis loop increases with increment of loading rate. The larger the loading rate, the longer the time is taken for the sample to reach equilibrium state. © 2016, Science Press. All right reserved.


Xiang Z.,Central South University | Yuan R.,China Railway First Group Co.
Applied Mechanics and Materials | Year: 2012

The construction geological condition is complex in the transition section from the inclined shaft to the main hole. There are two kinds of construction schemes. After the comparison of the advantages and disadvantages of the two different construction schemes, it has selected the construction scheme of the rectangular pilot tunnel vertical to the main hole. This paper solve the construction problem of the transition section from the inclined shaft to the main hole of large cross section tunnel of passenger dedicated line under complicated geological conditions. According to the previous research results, the method can be used to large-cross section tunnel. The scaffold design and auxiliary construction measures is detailed. Compared with the expected duration, it completed the transition construction ahead of time with the speed superior to the ones of other similar works, and forming a safe and efficient construction situation. © (2012) Trans Tech Publications, Switzerland.


Nie Z.-H.,Central South University | Liu Y.,Central South University | Luo C.-P.,China Railway First Group Co. | Wang X.,Central South University
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2015

In order to solve the frost heave problem in subgrade of passenger dedicated line in cold region, a graded gravel model was grouted by using grouting pump and vacuum pump to obtain the grouting parameters. Electron microscope scanning, penetration test and freeze-thaw cycle test were carried out to verify the frost heave effect of graded gravel after grouting improvement. The results show that when the viscosity of slurry reaches to 2.50 MPa·s, the groutability of slurry can meet the requirement of grouting test. The graded gravel after grouting is well bounding with the slurry and the permeability of the samples decreases from 6.8×10-3 cm/s to 1.4×10-10 cm/s. The permeability of graded gravel reduces significantly after grouting improvement. The maximum frost heave ratio is 0.25%, which meet the requirement of the uneven deformation in subgrade of passenger dedicated line. The model test demonstrates that the permeability and frost heave ratio can be effectively improved by grouting, which provides a reference for field grouting test of graded gravel in surface layer of subgrade. ©, 2015, Editorial Department of Journal of Chang'an University (Natural Science Edition). All right reserved.

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