To address the challenge of recovering high⁃grade ore from the bottom pillar in the mining of steeplydipping thin orebodies in the Lizi Gold Mine of Gansu, an artificial false bottom construction technology based on light⁃weight energy⁃absorbing material was adopted to achieve efficient underground bottom pillar resource replacement.Based on the theory of elasticity for thin plate, a mechanical model of the artificial false bottom was established, and thestress distribution and deformation characteristics of the backfill under self⁃weight and upper load were systematicallyanalyzed. The optimal thickness, concrete strength, and reinforcement scheme of the artificial false bottom were thendetermined and verified through numerical simulation. The application of lightweight energy⁃absorbing materials signif⁃icantly reduced the structural weight and construction period while greatly enhancing mechanized construction efficiencyand labor safety. This approach is of great significance in promoting green and sustainable mining.