LIU Chang, LIU Zheng-he, ZHANG Jun-wen, et al. Effect of mining face length on the evolution of spatial structure of overlying strata and the law of underground pressure in large mining height face[J]. 2018, 39(2): 691-698.
LIU Chang, LIU Zheng-he, ZHANG Jun-wen, et al. Effect of mining face length on the evolution of spatial structure of overlying strata and the law of underground pressure in large mining height face[J]. 2018, 39(2): 691-698.DOI: 10.16285/j.rsm.2016.0400.
The increased length of mining face is one of the significant factors to increase the underground pressure in longwall (LW) face. The physical model tests showed the fractured shape of overlying stratum exhibited as trapezoid platform structure (TPS) after roof caving. Its forming mechanisms were investigated in detail and the calculation principle of geometric parameters of TPS. The effect of mining face length on the fracturing behaviour of overlying strata was studied according to the TPS
and then the relationship between the TPS and key strata theory was also given. The thin plate theory was applied to calculate roof weighting interval. Then
the influence of mining face length on TPS’s parameters was analysed as well as underground pressure. The results show that due to TPS-shaped fracturing characteristics of overlying strata
the thickness of loading layers and roof weighting intensity decrease with the decrease of mining face length. Field measurements were conducted in LW1305 with the face length of 85 m and in LW1302 with the face length of 180 m in mine No.2 of Zhaozhuang. The measured data show that the resistance of the supports should not be less than 4 738 kN and 7 623 kN in LW1305 and LW1302
respectively
and the roof is maintained well with the resistance of 5 500 kN in LW1305 and 7 800 kN in LW1302.