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Mechanical analysis of basic roof fracture mechanism and feature in coal mining with partial gangue backfilling
Open Geosciences ( IF 2 ) Pub Date : 2020-10-12 , DOI: 10.1515/geo-2020-0153
Yin Wei 1 , Bai Xiaomin 2 , Wu Jingke 3 , Zhang Ran 1 , Liu Chao 1 , Zhang Ran 1 , Tang Yunxin 1
Affiliation  

Abstract Coal mining with partial gangue backfilling (CMPGB) method has the advantages of both high filling efficiency and excellent workface capacity, which breaks through the technical bottleneck of full-section backfilling mining. In order to reveal the fracture mechanism and characteristics in CMPGB workface, this paper presents a comparative analysis of the filling ratio of different filling patterns in CMPGB. A local composite elastic foundation mechanical model of basic roof in CMPGB was established using thin elastic plate theory. Then, Galerkin’s semi-analytic solution process was designed according to local composite elastic foundation characteristics. A deflection equation of the basic roof was derived, and a critical condition of the basic roof breakage was given. Based on engineering calculation example of Ji15-31010 workface of Pingdingshan No. 12 Coal Mine, the following conclusions are drawn. (1) At the basic roof of caving section, tensile-shear failure occurred in workface, cutoff position, and transition section, while compressive-shear failure occurred in the central part of the goaf. The basic roof showed a typical local “C–X” failure characteristic. (2) The value of first caving span decreased from 32.7 to 31.4 m as the elastic foundation coefficient of backfilling body increased from 70 × 106 to 120 × 106 N/m3, with a decreasing amplitude of only 4.1%. The increase of density of backfilling body only changed the support structure of backfilling section and had an insignificant effect on the first caving span. (3) The value of the first caving span decreased from 59.1 to 21.68 m as the length of caving section increased from 40 to 140 m, indicating that the first caving span was mainly influenced by the length of caving section. The measured value of the first caving span of Ji15-31010 CMPGB workface was 29.8 m, which was close to the theoretical value of mechanical model.

中文翻译:

部分矸石充填采煤中基本顶板破裂机理及特征力学分析

摘要 部分脉石充填(CMPGB)法采煤具有充填效率高、工作面产能好的优点,突破了全断面充填开采的技术瓶颈。为了揭示CMPGB工作面的断裂机理和特征,本文对CMPGB不同充填方式的充填率进行了对比分析。应用薄弹性板理论建立了CMPGB基础屋盖局部复合弹性地基力学模型。然后,根据局部复合弹性地基的特点,设计了Galerkin的半解析求解过程。推导了基本顶板的挠度方程,给出了基本顶板破损的临界条件。以平顶山十二矿J15-31010工作面工程计算为例,得出以下结论。(1) 崩落段基本顶板工作面、截断位置和过渡段发生拉剪破坏,采空区中部发生压剪破坏。基本屋顶表现出典型的局部“C-X”破坏特征。(2)随着充填体弹性地基系数从70×106增加到120×106 N/m3,第一次崩落跨度值从32.7下降到31.4 m,下降幅度仅为4.1%。回填体密度的增加只改变了回填段的支撑结构,对首放跨度影响不大。(3) 第一个崩落跨度值从59.1降低到21。68 m,随着崩落段长度从 40 m 增加到 140 m,表明第一个崩落跨度主要受崩落段长度的影响。Ji15-31010 CMPGB工作面首放跨实测值为29.8 m,接近力学模型理论值。
更新日期:2020-10-12
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