Stability analysis of the inner dump with inclined base considering anti-slip pillar

The tilted angle of the coal seam leads to the tilted base of the discharge field in the corresponding area, causing the stability of the inner dump to be reduced and prone to sliding. In order to investigate the application effect and mechanism of anti-slip coal pillar in the tilted-base earth dumping site of open-pit mines, taking the tilted base earth discharge field of an open-pit mine in the research object, the theoretical analysis of the tilted base without anti-slip coal pillars and the discharge step under the condition of leaving anti-slip coal pillar at the foot of the slope are made respectively, and the calculation formula of slope stability in the two cases are derived based on the method of limiting equilibrium. Taking the angle of inclination of the basement stratum and the discharge height of the soil disposal site as the variables for research, it was obtained that the angle of inclination of the basement stratum α or the height of the soil disposal H and the slope stability coefficient Fs were negatively correlated with the inverse proportionality function, the angle of inclination of the basement stratum had a greater influence on the slope stability, and the height of the discharge height of the soil disposal site had a second greater influence on the stability of the slope. Numerical simulation analysis was carried out by FLAC3D software adopting the strength reduction method before and after the coal columns were set up in the discharge field, which was basically consistent with the theoretical results, and concluded that setting up 10m anti-slip coal columns under the current geologic conditions can improve the stability by 5%, which theoretically reveals the influence of setting up anti-slip coal columns on the slope stability of the discharge field. Finally, the parameters of anti-slip coal pillar setting are studied, with the height of coal pillar setting h and slope angle of coal pillar setting β as the research object, the setting height of anti-slip coal pillar and the stability coefficient are in a positive quadratic function, and the slope angle of anti-slip coal pillar has an inverse effect on the stability coefficient and the effect is small, which will provide references for the subsequent research on the installation of anti-slip coal pillars on the side slope of the soil disposal site and the measures to improve the stability of side slopes through the setting of anti-slip coal pillars. The study will provide a reference for the subsequent research on the installation of anti-slip coal pillars and the measures to improve slope stability by leaving anti-slip pillars.