Tweet Share

• Send by email

  Send by email

  

  Key technology of auxiliary air pressure balanced mode for shield tunnelling

  When tunnelling under common mode, shield usually performs with large load, and high cutter tool consumption in the mixed face condition with water-rich and good air-tightness layer, or in the rock layer with deep overburden and fissure water developed. In this case, the screw conveyor spewing usually occurred, and the efficiency of shield tunnelling is reduced and tailskin grouting quality decreased. By analyzing and concluding the knowledge gained from the construction practice of the Guangzhou Metro Line 1,2,3,6,9 and Line 13,21, this paper puts forward clearly the definition, advantage and disadvantage of Air Pressure-Balanced Mode (APBM) of shield tunnelling. Furthermore, this paper also discusses the key technology of APBM and its concomitant risk and countermeasure, which provides significant guidelines for the shield tunnelling under the similar ground condition. Shield tunnelling, Auxiliary air pressure balance, concomitant risk, prevention in emergency. For rock layer with deep overburden or rich fissure water (see Figure 1) and for composite formation with rich water and good air tightness, high load for shield, cutter consumption and water spewing occurred often with vicious cycles of “driving, spewing, cleaning, segment erection” when the conventional full earth pressure mode of shield tunneling was adopted, which, meanwhile, lead to slow progress, low efficiency, poor tailskin grouting quality, accelerated damage of tailskin brushes and the cutter tool, etc..In order to solve this problem, the first attempt for application of the APBM shield tunneling technology was made to Guangzhou Metro Line 1 in 1996. Two EPBMs made by Kawasaki were chosen to drive the two sections of Martyrs’ Park Station~Peasant Movement Institute Station ~Gongyuanqian Station. Geological conditions of tunnel section from top to bottom were: hard at the top parts, with plastic, residual clay layer (good air tightness); middle parts were the complete and strong weathered the rock; bottom parts were medium and light weathered rock. The strong and medium weathered rock were fissures developed and water riched. The cutter tool configuration was not reasonable. In order to control the ground and building settlement, machine advanced with the earth pressure mode. while tunneling, load increased, the experienced Japanese contractors was also struggling with screw conveyor spewing, suffering under vicious cycle of “mining, spewing, cleaning, segment erection”. It spent longer time on cleaning than normal advancing. as well as, more concern on tailskin grouting as quality were no guarantee, on segment quality as deformation while segment ring release from tailskin, on tailskin brushes and cutter consumption increased. Mr.

  Recipient :

  Name ^* :

  E-mail address ^* :

  ^* Required fields

  Send   or  Cancel

• Print