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以果洛龙洼金矿开采为工程背景,首先基于弹塑性理论,将中深孔开采急倾斜薄矿体采场顶板简化为两端固支的高次超静定梁,并建立力学分析模型。分析顶板4个不同的受力变形阶段,即弹性阶段、顶板两端出现塑性区阶段、顶板两端破裂并变为简支阶段、整个顶板成为塑性流动机构阶段,确定不同阶段的顶板极限跨度,分别为7.38,9.27,9.53和10.43 m。然后基于Kachanov蠕变损伤理论对不同阶段顶板损伤断裂时间进行预测,不同受力阶段顶板断裂时间分别为51.8,15.3及14.5 d,并给出顶板两端损伤断裂时间与顶板跨度的函数关系图,基本呈三次函数关系。最后根据现场应力监测,对开采过程中围岩应力变化规律进行研究,分析表明随着工作面的推进,采场围岩应力经历缓慢增加、急剧增加、急剧降低和缓慢恢复4个阶段。
Taking the Gololongwa gold mining as the engineering background, based on the elasto-plastic theory, the roof of the stope with thin dip in deep-hole mining is reduced to a high-order statically indeterminate beam with two ends supported and a mechanical analysis model . Four different deformation stages of the roof, that is, the elastic phase, the plastic zone appears at both ends of the roof, the two ends of the roof crack and become the simple support phase, the whole roof becomes the stage of plastic flow mechanism, Respectively 7.38, 9.27, 9.53 and 10.43 m. Then, based on Kachanov creep damage theory, the damage time of roof damage in different stages is predicted. The roof failure time is 51.8, 15.3 and 14.5 d respectively under different stress stages, and the relationship between the damage and fracture time of roof and the roof span is given. The basic three functions. Finally, according to the on-site stress monitoring, the change law of surrounding rock stress during the mining process is studied. The analysis shows that with the advancement of working face, the surrounding rock stress of the stope experiences slowly increase, sharp increase, sharp decrease and slow recovery.