Abstract: In order to ensure the mining stability and resources recovery of the offshore ore,the artificial false bottom was designed and applied to the -165 m middle-segment in Sonshandao Gold Mine.Mechanical model was founded to analyze the instability mechanism of the artificial false bottom based on the elasticity theory,and numerical simulation was applied to analyze the stability of the artificial false bottom with different thicknesses.The stress and displacement characteristics under the artificial false bottom with different thicknesses are analyzed to obtain its stability.Results showed that the range of tensile stress on artificial false bottom with thickness of 0.4 m and 0.5 m,exceeding that tensile strength,accounts for 80% and 26.7% of mining approach width respectively.The maximum tensile stress was distributed on the middle of the artificial false bottom,and the vertical displacement of the false bottom was uneven settlement,which increased with the reduction in thickness of the artificial false bottom.The overall stability of the artificial false bottom with the thickness of 0.6 m,whose tensile stress was less than the tensile strength and whose settlement of the false bottom was uniform,was better apart from the higher costs.So the thickness of the artificial false bottom was suggested to be 0.5 m.The results of the analysis applied to practical engineering showed that the thickness parameter was safe,economical and reasonable.

Key words: Offshore orebody, Artificial false bottom, Instability mechanism, Engineering application