水-热耦合下露天矿冻结期靠帮开采边坡稳定性研究

Research on slope stability of open-pit mining during freezing period under hydrothermal coupling

以宝日希勒露天矿北部端帮为研究对象,建立了边坡地质模型,基于水热耦合理论,通过COMSOL有限元分析软件分析了不同温度下冻结层厚度变化,利用GEO-slope软件对不同厚度下边坡进行稳定性分析,揭示了帮坡角改变对边坡稳定性的影响规律,确定了冻结期靠帮开采合理的帮坡角。研究表明:最佳靠帮开采时期为2月中旬至3月中旬,此时最大冻结层厚度约为3.4 m;在3.4 m冻结层作用下,冻结期边坡稳定性系数相较于非冻结期稳定性系数提升了7.3%;冻结期靠帮开采的合理帮坡角为29°,可多回收煤炭8.4万t。提出了增大内排台阶宽度到40 m的过渡期措施,保障了端帮由冻结期向解冻期过渡的安全。

The geological model of slope was established by taking the northern end of Baorixile Open-pit Mine as the research object.Based on the hydrothermal coupling theory,the thickness changes of frozen layer under different temperatures were analyzed by COMSOL finite element analysis software.GEO-slope software is used to analyze the slope stability under different thicknesses,revealing the influence law of slope angle change on slope stability,and determining the reasonable slope angle of slope mining in freezing period.The results show that the optimum mining period is from mid-February to mid-March,when the maximum frozen layer thickness is about 3.4 m.Under the action of 3.4 m frozen layer,the stability coefficient of slope in frozen period increases by 7.3%compared with that in non-frozen period.During the freezing period,the reasonable slope angle is 29°,and more than 84,000 t coal can be recovered.A transitional measure of increasing the width of the inner row step to 40 m is proposed to ensure the safety of the transition from freezing period to thawing period.