近海矿体开采人工假底厚度优化及工程应用

Thickness Optimization and Engineering Application of Artificial False Bottom in Offshore Ore Mining

三山岛金矿为了保证矿山近海矿体开采的稳定性和资源的回收率,设计在-165 m中段施工人工假底。通过建立力学模型,应用弹性力学理论对人工假底的失稳机理进行分析,然后应用数值模拟方法对不同厚度的人工假底下开采进路的稳定性进行分析。通过计算分析不同厚度人工假底下开采进路顶板的应力、位移变化特征,得出不同厚度人工假底的稳定情况。结果表明:厚度为0.4 m和0.5 m的人工假底拉应力超出其抗拉强度的分布区域在进路宽度方向上分别占80%和26.7%,最大拉应力分布在假底中部,假底的垂直位移呈不均匀沉降,且假底厚度越小,不均性越大;厚度为0.6 m的人工假底拉应力均未超出假底抗拉强度,且位移沉降均匀,整体稳定性较好,但施工成本较高。因此,建议人工假底厚度为0.5 m。将优化结果应用于工程实践,结果表明该参数安全经济合理。

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.