Research on deformation mechanism of gently inclined rock convex slope in open-pit coal mine under the action of rain

To reveal the shear creep failure mechanism and control measures of gently inclined rock convex slope under heavy rainfall. In this study, the convex slope of Baorixile open-pit coal mine is taken as an example. The Newton force field monitoring and FLAC^3D numerical simulation are used to study the internal Newton force evolution law of the gently inclined rock convex slope under freezing-thawing action, and the deformation law and plastic zone distribution characteristics of the convex slope under the condition of no support and high prestressed anchor cable support under the action of heavy rainfall are analyzed. The results show that typical convex slope is formed in open-pit coal mining, and the convex slope deforms significantly under the combined action of local stress concentration and unloading rebound deformation. During the thawing period of convex slope, the Newton force on the northern slope decreases, while the Newton force on the eastern slope increases. Under the action of heavy rainfall, the bulk density of rock mass increases, resulting in the formation of fissure water pressure in the slope, which increases the sliding power of the rock mass of the slope. Meanwhile, the strength of the carbonaceous mudstone between coal seams is weakened by water, resulting in the formation of a gently inclined structural plane, which leads to the overall horizontal shear sliding of the rock mass along the soft structural plane. The high prestressed anchor cable can effectively increase the integrity of the gently inclined rock slope and reduce the slope plastic deformation caused by rainfall. The research work in this study provides a basis for deformation control and support design of convex slope in Baorixile open-pit coal mine.