| 摘要: |
| 为甄别复杂采空区群中的薄弱单元,以某地下石灰石矿山采空区群为工程实例,通过构建离散振动力学模型,和应变改变量相关影响因素分析,创新地提出薄弱单元损伤模态识别法,给出甄别流程,并从算例计算和工程实际应用两方面验证其可靠性。研究结果表明:自振频率和应变模态的甄别指标能准确识别采空区群中的薄弱单元;单体和双体单元损伤都会使采空区群的自振频率甄别指标IM(k)值大于0,损伤区域的应变模态甄别指标IN(x)值会明显出现凸起,随着损伤程度增大,IM(k)值和IN(x)峰值越来越大；仅顶板B1损伤时,高阶IM(k)比低阶更灵敏反映损伤变化程度,第四阶指标识别效果更优；仅矿柱Z6损伤时,第二、四阶IM(k)识别效果更优；B1和Z6共同损伤时,IM(k)对B1损伤程度变化较于Z6更为敏感,第二阶IM(k)识别效果更佳。研究成果为地下采空区群安全定量评估开辟了一条新方向。 |
| 关键词: 离散振动力学模型法 薄弱单元 甄别 自振频率 应变模态 |
| DOI：10.11918/202111071 |
| 分类号:TU443 |
| 文献标识码:A |
| 基金项目:国家自然科学基金面上项目(51974135) |
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| Identification of weak units in complex goaf group based on damage mode recognition method |
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JIANG Lichun1,2,SHAO Fan2
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(1.School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China; 2.Institute of Safety Science & Engineering, South China University of Technology, Guangzhou 510640, China)
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| Abstract: |
| In order to identify the weak units in the complex goaf group, taking the goaf of an underground limestone mine as an example, through the construction of the discrete vibration mechanics model and the analysis of the related influence factors of the strain change, a damage mode identification method for weak units is innovatively proposed. The screening process is given, and its reliability is verified from two aspects: calculation examples and practical engineering application. The research results show that the screening index of natural frequency and strain mode can accurately identify the weak units in the goaf group. Both single-body and double-body unit damage will cause the natural frequency discrimination index IM(k) of the goaf group to be greater than 0, and the value of strain modal discrimination index IN(x) of the damaged area will be obviously convex. With the degree of damage increasing, the value of IM(k) and the peak value ofIN(x) peak value are getting bigger and bigger. Under only B1 damage conditions, the higher-order IM(k) is more sensitive than the lower-order to reflect the degree of damage, and the fourth-order index recognition effect is better; Under only Z6 damage conditions, the second and fourth-order IM(k) recognition effect is better excellent. Under B1 and Z6 damage conditions, IM(k) is more sensitive to the changes of B1 damage degree than Z6, and the second-order IM(k) recognition effect is better. The results have opened up a new direction for the quantitative evaluation of the safety of the underground goaf group. |
| Key words: discrete vibration mechanics model method weak elements screening natural frequency strain modal |
