ISSN 2096-4498

   CN 44-1745/U

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Tunnel Construction ›› 2020, Vol. 40 ›› Issue (S1): 396-403.DOI: 10.3973/j.issn.2096-4498.2020.S1.052

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Construction Technology of Large Diameter Slurry Shield in Strong Permeable Sand Pebble Stratum with Shallow Overburden Soil

YAO Yinbin   

  1. (Yuanjiang River Crossing Project Office of China Railway 14th Bureau Group Co., Ltd. Changde 415000 HunanChina)
  • Online:2020-08-30 Published:2020-09-16

Abstract: In order to solve the problems of receiving largediameter slurry shield in strong permeable sand pebble stratum with shallow overburden, based on large diameter slurry shield tunnel of Yuanjiang  in Changde City, dry receiving construction technology is proposed. The stability of the whole structure in end reinforcement area is improved and the conditions for shield acceptance are satisfied by using the joint reinforcement methods of RJP superhigh pressure jet grouting, vertical freezing and plastic concrete diaphragm wall in the end reinforcement area. In the process of shield dry receiving, by controlling various construction parameters and grasping the key points of construction timing accurately, shield machine smoothly passes through the existing pipeline and reinforcement area, and the maximum settlement of the pipeline and the surface is controlled within 6 mm and 5 mm respectively so as to ensure the accurate exit of the shield machine. In addition, portal brushes are installed in the steel ring of the portal to prevent soil loss when shield machine exits the tunnel. Meanwhile, synchronous grouting volume is increased and segments are connected and fixed with channel steel to ensure shield tail and support safety during the process of shield machine leaving the tunnel.

Key words: shallow overburden soil, strong permeable sand pebble stratum, large diameter shield, dry receiving, slurry shield, control of tunneling parameters, end reinforcement

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