| 大块度关键块动态结构力学行为及响应特征研究 |
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| 引用本文： | 刘一扬,宋选民,朱德福,李竹.大块度关键块动态结构力学行为及响应特征研究[J].岩土力学,2020,41(3):1019-1028. |
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| 作者姓名： | 刘一扬 宋选民 朱德福 李竹 |
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| 作者单位： | 1. 太原理工大学 原位改性采矿教育部重点实验室，山西 太原 030024；2. 中国矿业大学 煤炭资源与安全开采国家重点实验室，江苏 徐州 221116；3. 太原理工大学 矿业工程学院，山西 太原 030024 |
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| 基金项目： | 国家自然科学基金项目（No.51904200）；中国矿业大学煤炭资源与安全开采国家重点实验室开放课题资助项目（SKLCRSM19KF019） |
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| 摘 要： | 西部地区采场顶板厚而坚硬,破断岩块常形成大块度关键块,围岩稳定性差,支架响应强烈,研究块体动态结构力学行为对西部地区采场围岩控制具有重要意义。根据大块度关键块相对回转形成的动态结构建立运动力学分析模型,按照块体间几何关系推导出挤压面积随回转角的变化关系,将块体相对回转的动态过程分为3个回转阶段。基于"砌体梁"理论推导出不同阶段块体所受挤压力与回转角的关系,对结构稳定性及力学行为进行分析。结合失稳条件,以支架工作阻力为响应特征,找到回转过程中结构最易失稳点,提出工作阻力确定方法,并得到现场实证。理论计算结果表明,在大块度条件下,随着回转角θ的增大,挤压力T1总体上呈增大的趋势;当块度i<1时,T1随θ变化呈二次抛物线规律变化;而当i>1时,曲线逐渐表现为线性变化,且块度越大T1随θ变化幅度越小。通过失稳条件分析,揭示了大块度关键块在回转初期易发生滑落失稳,而抗回转变形失稳能力较强;针对块度i较大,结构自稳性弱、支架响应强烈的特点,需设计合理的支架工作阻力,分析3个回转阶段受力情况,得出块体处于回转初期与中期的临界角度时最易失稳,并给出该易失稳状态下工作阻力计算公式。
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| 关 键 词： | 大块度关键块 动态结构 挤压面积 稳定性分析 响应特征 |
| 收稿时间： | 2019-06-14 |
| 修稿时间： | 2019-08-21 |
Dynamic structural mechanical behavior and response characteristics
of large key blocks |
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| LIU Yi-yang,SONG Xuan-min,ZHU De-fu,LI Zhu.Dynamic structural mechanical behavior and response characteristics
of large key blocks[J].Rock and Soil Mechanics,2020,41(3):1019-1028. |
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| Authors: | LIU Yi-yang SONG Xuan-min ZHU De-fu LI Zhu |
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| Institution: | 1. Key Laboratory of In-situ Property-improving Mining of Ministry of Education, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China;
2. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China;
3. College of Mining Technology, Taiyuan University of Technology, Taiyuan, Shanxi 030024, China |
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| Abstract: | The roof of the stope in the western region is thick and hard. The broken rock often forms large key blocks. The stability of the surrounding rock is poor with leads to strong support response. Thus, investigating the dynamic structural mechanical behavior of blocks is of great significance to the control of stope surrounding rocks in the western region. According to the dynamic structure formed by the relative rotation of key blocks, a kinematic mechanical analysis model is established. In this study, according to the change of geometric relationship between blocks, the relationship between the extrusion area and the angle of rotation is derived, and the dynamic process of the relative rotation of blocks is divided into three rotation stages. Based on the "voussoir beam" theory, the relationship between the extrusion force and the rotation angle of blocks in different stages is deduced, the structural stability and mechanical behavior are analyzed. Combined with the instability conditions, the working resistance of support is taken as the response characteristic, finding the most unstable position of the structure during the turning process, and then a method of calculating support working resistance is developed, and its correctness of the formula is proved by practical cases. The theoretical calculation results show that: with the increase of the rotation angle θ, the extrusion force T1 generally shows an increasing trend. When the blockness i<1, T1 increases or decreases in a quadratic parabola with θ change. However, when i>1, the curve gradually shows a linear change. As the blackness is large, the increase rate of T1 with θ is smaller. From the analysis of instability conditions, it can be revealed that the large key blocks are prone to slip instability in the early stage of rotation, but its anti-rotation deformation instability ability is relatively strong. For the characteristics of large blockness, weak self-stability of the structural and strong response of the
support, it is necessary to design a reasonable support working resistance. By analyzing the stress conditions in the three rotation stages, it is found that the most unstable block is at the critical angle between the initial and middle rotation stage. Finally a formula of calculating the working resistance of support is given in the state of instability. |
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| Keywords: | large key blocks dynamic structure extrusion area stability analysis response characteristics |
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