Equipment recovery passage (ERP) is being widely employed in longwall panel for the purpose of recovering heave mining equipment at the end of mining stage. The stability of the ERP, however, is always difficult to control although powerful supporting structures are employed, which restricts its further promotion. In the present paper, we focused on the ERP’s stability control through reducing the abutment stress imposed on the ERP’s surroundings rather than solely increasing roadway support intensity, based on a rigorous case study in China. First, the dynamic evolution of the abutment stresses, corresponding plastic zone and deformations in the surrounding rock of the ERP were analyzed through a meticulously validated FLAC3D numerical simulation, as the longwall face moved with different velocity. The simulated results indicate that the faster the longwall face moved, the lower the abutment stresses, the narrower the plastic zone and the smaller the deformations were. In terms of these analyses, two suggestions were proposed, including increasing longwall face moving velocity and roof structure optimization, and corresponding technologies were introduced, and potential effect were verified as well. Conclusions and suggestions of this paper might be helpful for increasing the flexibility of the ERP in similar geotechnical conditions.
Marine sediments were dissolved by HNO3-HF-HCIO4 in a sealed container at low pressure; I-IF was evaporated in an open container and salts were dissolved in HCl by heating, then transferred to 2% HNO3 solution. A total of 45 elements, including Li, Be, So, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Cd, In, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, TI, Pb, Bi, Th and U, were measured by inductively coupled plasma mass spectrometry (ICP-MS). Condi-tions and sample experiments showed that this procedure defines a good experimental method which has the advantages of clear interference, easy operation and reliable results. The concentrations of the 45 elements could be used for resource exploration, envi-ronmental assessment and academic research. 相似文献