Similar Material Simulation Study on Dam Movement and Deformation Law of Deep Coal Seam Mining Under Dam

ABSTRACT In the fully mechanized caving mining of deep coal seams, the dam structure has the characteristics of small size, large burial depth, and significant height‐to‐depth ratio. Traditional methods are difficult to accurately calculate its movement and deformation. Therefore, this study proposes to separate the analysis of the surface and the dam structure's movement and deformation, quantitatively invert the dam deformation state through the surface deformation shape, obtain the deformation law of the dam under different advance lengths, and establish a spatio‐temporal inversion mechanism of local amplification effect. Taking the impact detection of a certain mine dam working face as an example, the study shows that the dam has undergone an alternating process of tensile failure to compressive reduction, but the sequence of tensile and compressive conversion at different parts is different. At the initial stage of the impact, the dam's foot on the anticline side first experiences tensile failure, then affects the upstream slope side, and finally spreads to the middle of the dam; the tensile and compressive conversion also follows the sequence from the anticline side to the upstream slope side and finally to the middle of the dam. Through the local amplification analysis method of replacing coal seam mining with shallow layer mining, the tensile and compressive alternating failure characteristics of the dam evolving from the backwater slope to the water‐facing slope and then to the middle are revealed. The measured maximum settlement value is 7.077 m, with an error of only 0.077 m compared to the simulation result of 7 m for similar materials, verifying the feasibility, rationality, and scientificity of this method. This paper constructs a numerical model that accurately reproduces the deformation of the surface and the dam, analyzes the formation mechanism of the subsidence basin, and determines the excavation volume corresponding to each advance step based on the probability integral method or full‐scale numerical simulation.