Abstract:
The increase in the working face length will cause the stope to exhibit new mine pressure characteristics different from those of ordinary working faces. For instance, as the working face lengthens, the support resistance of hydraulic supports transitions from single-peak to multi-peak patterns. This reduces the stability and adaptability of hydraulic supports in ultra-long working faces, which is not conducive to the high-yield and high-efficiency construction of mines. In response to the problems such as the unclear load on the top beam of the hydraulic support in the ultra-long working face and the unclear mechanical characteristics after loading, taking the 132202 ultra-long working face of Xiaobaodang No.2 Mine as the background, a two-dimensional continuous beam model supported on elastic supports was established according to the relationship between the support and the surrounding rock. The matrix displacement method was used to calculate the deflection distribution of the entire roof length. The differential equation of a single-span beam was used to solve the deflection distribution of the top beam of the hydraulic support and the load distribution function along its width direction. By coupling with the load function along the beam length direction, the uneven load distribution function above the top beam was obtained. The distribution characteristics of the uneven load above the top beam in terms of magnitude and action position after being equivalent to a concentrated force were analyzed. The 3DEC numerical simulation results with pile structural units inserted as supports and the on-site pressure data of the hydraulic support were used to support the theory. The data analysis results achieved the unity of theoretical calculation, numerical simulation, and on-site data. The uneven load was imported into ANSYS to analyze the mechanical response of the hydraulic support affected by the uneven load. Comparisons were made with the partial-load and torsion conditions of the top beam under the equivalent load level, as well as with the support conditions under different uneven loads at other positions on the working face. The research results show that the two-dimensional continuous beam model can explain the three-peak pressure characteristics of the ultra-long working face to a certain extent. The uneven load distribution in ultra-long working faces demonstrates distinctive patterns: load irregularity with relatively low intensity at both ends, while exhibiting uniform load distribution with higher intensity at peak pressure zones. Meanwhile, the finite element analysis results prove that the unbalanced loads located at both ends of the ultra-long working face have a more inclined influence on the hydraulic support towards the torsional loading condition of the top beam. The risk of lateral overturning of the support is negatively correlated with the degree of load unevenness. The research deepens the application of beam models in mining face scenarios, with the findings providing theoretical guidance for the design of hydraulic supports in ultra-long working faces.