Application and evaluation of ground surface pre-grouting reinforcement for 800-m-deep underground opening through large fault zones

Deyu Qian, Nong Zhang, Mingwei Zhang, Hideki Shimada, Peng Cao, Yanlong Chen, Kai Wen, Sen Yang, Nianchao Zhang

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Faults are complex geological conditions that are commonly encountered during underground excavation. Many support schemes, such as using a single pilot heading method and 30-m-long borehole pre-grouting, have been implemented during the pilot excavation of an 800-m-deep underground opening that passes through large fault zones in East China. However, various geo-hazards, including groundwater inrush, debris flow, and roof collapse, are still occurring, which seriously threaten tunneling safety. To eliminate the geo-hazards and ensure tunneling safety, ground surface pre-grouting (GSPG) was proposed and implemented for the first time to reinforce the regional engineering rock mass for this proposed 800-m-deep underground opening passing through large fault zones. The minimum grouting pressure of GSPG at a depth of 800 m below the surface is put forward based on hydraulic fracturing theory, providing valuable guidance for GSPG engineering practice. Engineering practice demonstrates that GSPG eliminates geo-hazards, improves the objective rock mass stability, and ensures tunneling safety. Field measurements indicate that the displacement velocity of the surrounding rock shows an obvious fluctuation response under the influence of GSPG, and the impact of GSPG on the stability of the 800-m-deep underground opening that has been excavated dramatically decreases as the distance from the grouting borehole increases. Moreover, there is a strong negative exponential correlation between the maximum velocity of deformations and the distance from the grouting borehole. In addition, the safe distance underground during GSPG is greater than 137 m.

Original languageEnglish
Article number285
JournalArabian Journal of Geosciences
Volume10
Issue number13
DOIs
Publication statusPublished - Jul 1 2017

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grouting
reinforcement
fault zone
borehole
hazard
safety
engineering
excavation
evaluation
rock
debris flow
roof
groundwater

All Science Journal Classification (ASJC) codes

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

Cite this

Application and evaluation of ground surface pre-grouting reinforcement for 800-m-deep underground opening through large fault zones. / Qian, Deyu; Zhang, Nong; Zhang, Mingwei; Shimada, Hideki; Cao, Peng; Chen, Yanlong; Wen, Kai; Yang, Sen; Zhang, Nianchao.

In: Arabian Journal of Geosciences, Vol. 10, No. 13, 285, 01.07.2017.

Research output: Contribution to journalArticle

Qian, Deyu ; Zhang, Nong ; Zhang, Mingwei ; Shimada, Hideki ; Cao, Peng ; Chen, Yanlong ; Wen, Kai ; Yang, Sen ; Zhang, Nianchao. / Application and evaluation of ground surface pre-grouting reinforcement for 800-m-deep underground opening through large fault zones. In: Arabian Journal of Geosciences. 2017 ; Vol. 10, No. 13.
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