下向进路回采钢筋混凝土假顶稳定性分析

〗为确保下向进路采场高效安全回采，采用ABAQUS的损伤塑性模型对下向进路钢筋混凝土假顶进行稳定性分析，得到假顶的应力与位移分布规律，分别从假顶的应力分布、变形量对不同进路尺寸及假顶厚度的影响进行比较分析。结果表明，进路假顶产生的最大拉应力（089MPa）小于混凝土层的抗拉强度（127MPa）；最大压应力（416 MPa）小于混凝土层的抗压强度（119MPa）；假顶底部最易被拉裂位置为偏离假顶中央(05~1)m处；钢筋承载了大部分拉应力，受拉性能得到充分利用。在进路尺寸为3m×3m或者4m×3m时假顶厚度取06m，进路尺寸为4m×4m时假顶厚度取08m，假顶最大拉应力值均未超过混凝土的抗拉强度值，此时假顶较为稳定，便于进路维护与提高回采强度。研究结果对下向进路采场的安全生产提供技术保障。

Analysis on stability of reinforced concrete false roof in underhand drift mining

In order to guarantee the safety and mining efficiency of underhand drift stopes, the damaged plasticity model of ABAQUS was used to analyze the stability of reinforced concrete false roof in underhand drift, and the stress and displacement distribution of false roof were obtained from the simulation. The analysis and comparison were conducted on the stress distribution and the deformation of false roof to study the impact on different drift structure parameters and the thickness of false roof. The results showed that the maximum tensile stress (0.89 MPa) of the false roof is less than tensile strength (1.27 MPa) of concrete. The maximum pressure (4.16 MPa) of the false roof is also less than pressure strength (11.9 MPa) of concrete. The rupture prone zone locates at 0.5 1 m away from the center of false roof .The reinforcement bears most of the tensile stress value, and its tensile property is fully used. The thickness of false roof should be 0.6 m when the drift structure parameters is 3 m×3 m or 4 m×3 m, and the thickness of false roof should be 0.8 m when the drift structure parameters is 4 m×4 m, their maximum tensile stresses are less than tensile strength of concrete. Therefore, the false roof is relatively stable, and the maintenance of drift becomes easy and the recovering strength is enhanced. The results offer technical support for safety production of underhand drift mining.