Soil Engineering and Foundation

Soil Engineering and Foundation ›› 2019, Vol. 33 ›› Issue (6): 650-654.

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Optimization Study on Widening Excavation of an Existing Tunnel in Weak Rock Mass

The existing Housi Tunnel had two tunnel tubes in the weak rock mass, and it was decided to widen this tunnel into four tubes. The proposed CRD method had the disadvantages of complex excavation procedures, a relative high risk of temporary supporting system removal and longer construction schedule. The benching tunneling method was proposed to replace the CRD excavation method. The proposed benching tunneling procedure was simulated through numerical analysis and was verified through the construction monitoring. The results indicated that, the benching tunneling method is feasible for the excavation of large cross section tunnel and optimized excavation procedure used in the construction was successful.   

  1. (ZhangzhouLongyan Section Widening Engineering Co., Ltd. of XiamenChengdu Expressway, Longyan 364000)
  • Received:2019-08-31 Revised:2019-10-25 Online:2019-12-28 Published:2019-12-28

Abstract: The existing Housi Tunnel had two tunnel tubes in the weak rock mass, and it was decided to widen this tunnel into four tubes. The proposed CRD method had the disadvantages of complex excavation procedures, a relative high risk of temporary supporting system removal and longer construction schedule. The benching tunneling method was proposed to replace the CRD excavation method. The proposed benching tunneling procedure was simulated through numerical analysis and was verified through the construction monitoring. The results indicated that, the benching tunneling method is feasible for the excavation of large cross section tunnel and optimized excavation procedure used in the construction was successful.

Key words: Widening of Existing Tunnel, Weak Rock Mass, Excavation Optimization, Benching Tunneling Method