Rock and Soil Mechanics ›› 2019, Vol. 40 ›› Issue (1): 363-369.doi: 10.16285/j.rsm.2017.0996

• Geotechnical Engineering • Previous Articles     Next Articles

Rapid uncovering seam technologies for large cross-section gas tunnel excavated through coal seams using directional hydraulic fracturing

LI Dong1, 2, LU Yi-yu1, RONG Yao2, ZHOU Dong-ping3, GUO Chen-ye3, ZHANG Shang-bin3, ZHANG Cheng-ke2   

  1. 1. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China; 2. Jiangxi Research Institute of Transportation, Nanchang, Jiangxi 330038, China; 3. Chongqing Energy Investment Group Technology Co., Ltd., Chongqing 400060, China
  • Received:2017-05-17 Online:2019-01-11 Published:2019-01-31
  • Supported by:
    This work was supported by Major Project of the National Science and Technology (2011ZX05065), the Science and Technology Project of Jiangxi Provincial Department of Transportation (2017H0019, 2018H0042), the Science and Technology Key Project of Jiangxi Provincial Department of Transportation (2015C0067) and the Chongqing Science Fund for Distinguished Young Scholars (cstc2014jcyjjq 90002).

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Abstract: Based on the analysis of the characteristics of uncovering coal seam in gas tunnel, we propose a method of directional hydraulic fracturing by waterjet slotting, and also develop the waterjet slotting guide device. A rapid elimination technology system is formed for the large cross-section gas tunnel excavated through multiple coal seams, which is further applied to a project of Chongqing-Guizhou high-speed railway. The results show that the fracturing of hydraulic cracks is governed by the waterjet slotting obviously, and always expands along the coherent plastic zone formed by the directional hole cutting and hydraulic fracturing cracks in the coal seam. The permeability of coal seam is increased by 35–187 times, and the average gas extraction efficiency is 4.28 times and 12.73 times higher than that of conventional fracturing in adjacent coal seam of the same tunnel and conventional extraction technology in the same coal seam of adjacent tunnel, respectively, and the time of uncovering coal seam is 50% less than the expected. Directional hydraulic fracturing effectively weakens the damage to the surrounding rock by high-pressure water, and the vault settlement and horizontal convergence of tunnel are reduced by 18.3% and 16.4%, respectively.

Key words: large cross-section, gas tunnel, uncovering coal seam, directional hydraulic fracturing, waterjet slotting, outburst elimination

CLC Number: 

  • TU 432
[1] LIU Quan-sheng, PENG Xing-xin, LEI Guang-feng, WANG Jun-tao,. Geomechanical model test on excavation technology of supper-large cross-section ultra-shallow tunnel with cross rock pillar method [J]. , 2017, 38(10): 2780-2788.
[2] ZHANG Guang-chao, HE Fu-lian. Pillar width determination and surrounding rocks control of gob-side entry with large cross-section and fully-mechanized mining [J]. , 2016, 37(6): 1721-1728.
[3] LI Xue , ZHOU Shun-hua , GONG Quan-mei , CHEN Chang-jiang, . Evaluation of earth pressure around a deeply buried metro shield tunnel with a large cross-section under high water pressure conditions [J]. , 2015, 36(5): 1415-1420.
[4] SHI Yu-feng , YANG Jun-sheng , SHAO Hua-ping , LONG Yun , YANG Feng . Risk analysis and control study of super-shallow tunnel with large cross-section under water-rich channel [J]. , 2012, 33(S2): 229-234.
[5] YAN Hong, HE Fu-lian, XU Teng-fei, JIANG Hong-jun, GAO Sheng. Experimental study of bolt and cable truss system for large cross-section coal roadways under high stress [J]. , 2012, 33(S2): 257-262.
[6] JIANG Kun , XIA Cai-chu , BIAN Yue-wei. Optimal analysis of construction schemes of small space tunnel with bidirectional eight traffic lanes in jointed rock mass [J]. , 2012, 33(3): 841-847.
[7] WANG Ming-nian, GUO Jun, LUO Lu-sen, Yu Yu, Yang Jian-min, Tan Zhon. Study of critical buried depth of large cross-section loess tunnel for high speed railway [J]. , 2010, 31(4): 1157-1162.
[8] YANG Yong-bo, LIU Ming-gui, ZHANG Guo-hua, LI Qi. Analysis of construction parameter optimization for new large cross-section tunnel next to existing tunnels [J]. , 2010, 31(4): 1217-1226.
[9] GUO Jun，WANG Ming-nian，TAN Zhong-sheng，LUO Lu-sen. Anchoring mechanism and effect of systematic rockbolt for shallow buried loess tunnel [J]. , 2010, 31(3): 870-874.
[10] QU Hai-feng, ZHU He-hua, CAI Yong-chang . Discussion on calculation of loose load on extra-large cross-section and large-span road tunnel [J]. , 2008, 29(4): 989-994.
[11] XU Bin , WANG Kang-zhu , LI Ning , . 3D FEM analysis of excavating two intersecting tunnels in bad geology [J]. , 2007, 28(S1): 437-442.
[12] JIANG De-yi , LIU Chun , ZHANG Guang-yang , ZHENG Jin-long,. Technologies一 of whole cutting through coal seam and preventing collapse in highway tunnels [J]. , 2005, 26(6): 906-909.
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