Optimization and experimental study of sealing parameters of crossing boreholes based on creep effect

doi:10.16265/j.cnki.issn 1003-3033.2021.07.014

Abstract

Abstract: In order to address problems of difficult sealing of crossing borehole and low efficiency of gas drainage, with coal rock being regarded as elastic-plastic medium, a mechanical model of roadway surrounding rock was established considering creep effect. Then, control equation of grout flow was derived according to Dracy's law, and a coupling model of surrounding rock deformation and grout flow was constructed with permeability change as a bridge. Finally, the model was resolved by using COMSOL software. The numerical simulation results show that plastic softening zone around roadway expands from 4.69 m initially to be basically stable at 15.19 m in 100 days. And grout radius expands continuously with increase of grouting pressure, and tends to be stable when the pressure is higher than 2.8 MPa. Moreover, the average gas concentration of test boreholes reaches to 56.49%, which is 3.46 times that of traditional technology and still maintains a great drainage level in later period.

Key words: creep effect, crossing borehole, sealing parameter, coupling model, numerical simulation

CLC Number:

X936

ZHANG Junxiang, LIU Yanwei, REN Peiliang, HAN Hongkai, ZUO Weiqin. Optimization and experimental study of sealing parameters of crossing boreholes based on creep effect[J]. China Safety Science Journal, 2021, 31(7): 97-104.

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