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Shenzhen, China

Zhao Q.-J.,Guangzhou Metro Design and Research Institute Co. | Liu Z.-G.,Shenzhen Metro Group Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering

The anchor cable, as a mature technology, is widely applied in support of excavations and slopes in geotechnical engineering. But the cables with obvious length often bring great influence on the urban underground space after project completion, which is obvious obstruction in urban metro tunneling. The studies on the recycling pre-stressed anchor cables can provide reference for case under restricted conditions. The mechanism, technical maturity, safety reliability and economic benefits are discussed in adaptability and generalization of the recycling anchor cables. A deep excavation project of metro Line 9 in Shenzhen and other two cases are given for examples. Source

Li X.,Beijing Jiaotong University | Chen X.,Shenzhen Metro Group Co.
Journal of Construction Engineering and Management

Grouting control of shield tunneling is of paramount importance to reduce settlements of existing tunnels below-passed by shield tunneling along a curved alignment and in crowded urban areas. The methodology and scheme of the grouting control of shield tunneling is illustrated taking the first Earth Pressure Balanced (EPB) shield below-crossing existing interval tunnels from Kexueguan station to Dajuyuan station of the Shenzhen metro line No. 1, for example. A combination methodology of the observational method and the predefined design method was set up to deal with parameters concerning the grouting control of shield tunneling. Some parameters of the grouting control were predefined or suggested before the below-crossing, and other parameters might be adjusted during construction on the basis of the observational method. The scheme primarily consists of preparation work before the below-crossing, automatic motoring system used in operation tunnels, simultaneous backfilling grouting and grouting directly through segment holes. For the simultaneous backfilling grouting, enough grouting was filled in the tail void with shield advance. With the help of automatic motoring system, the grouting directly through segment holes was employed in light of the measured settlements of existing tunnels. The maximum of the final measured settlements of existing tunnels is about 70% of the predefined allowable settlement of 20mm, which shows that the grouting control of shield tunneling is effective in reducing settlements of existing tunnels. The grouting practice can be used as references in similar conditions. © 2012 American Society of Civil Engineers. Source

Qian W.J.,Southwest Petroleum University | Wu Y.F.,Shenzhen Metro Group Co. | Chen G.X.,Southwest Jiaotong University | Ouyang H.,University of Liverpool
Journal of Vibroengineering

The effects of a rail vibration absorber on suppressing short pitch rail corrugation are studied. Firstly, a rail vibration field test is carried out to analyze the vibration response of the rail with and without the vibration absorbers. Secondly, based on the hypothesis that friction-induced self-excited vibration of a wheel-rail system causes rail corrugation; two finite element models of a wheel-rail system and a wheel-rail-absorber system are established and analyzed. Both sets of rail vibration test results and theoretical results show that the rail absorbers can effectively reduce the friction-induced self-excited vibration of the wheel-rail system in the frequency range of 200-800 Hz, which corresponds to frequencies of short pitch rail corrugation. This may be a main reason that the rail vibration absorber can suppress the formation of short pitch rail corrugation. © JVE INTERNATIONAL LTD. Source

Wu C.,University of Chinese Academy of Sciences | Zhang Y.,Shenzhen Metro Group Co. | Jun X.,University of Chinese Academy of Sciences
Proceedings - 2014 IEEE Workshop on Advanced Research and Technology in Industry Applications, WARTIA 2014

In the present paper, we propose a gray-level image watermarking algorithm with high capacity based on bit decomposition and spread transform. To implement this algorithm, the gray-level digital watermark image is bit decompounded into a series of binary digital images, then the cover data extracted from the original cover image are projected to multiple orthogonal directions, while a binary image is embedded in each orientations. Testing results show that that watermark can be blindly extracted using this algorithm, and its the transparency and robustness are excellent. © 2014 IEEE. Source

Qi Z.,Beijing Jiaotong University | Qi Z.,Shenzhen Metro Group Co. | Li P.,Beijing Jiaotong University
Beijing Jiaotong Daxue Xuebao/Journal of Beijing Jiaotong University

Based the analysis of temporal-spatial effect and settlement mechanism, apply the fuzzy cluster analysis for 1497 ground surface settlements of 24 running tunnels in Beijing subway Line 5, represent the general distinction of shallow tunnel ground surface settlements regularities of distribution and the surface settlements trough width parameter inflexion point distance, and the loss ratio of stratum, gain the relation between surface settlement trough width parameter inflexion point distance and equivalence axial depth of burial, put forward a feasible surface settlement control criterion, and control method contains the 3 classes: prewarning, alarm and extreme. Research findings supply some reference value for cognitive shallow tunnel ground surface settlements regularities of distribution and develop control standard. Source

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