国内典型顶板条件工作面矿压显现规律

Characteristics of strata pressure behavior of working face under typical roof conditions in China

  • 摘要: 长期以来顶板灾害在煤矿灾害事故中始终占据较大比例,一直是困扰煤矿安全生产的难题。矿压规律分析对顶板灾害的有效防控至关重要,目前,大多研究仅针对单一矿井或个别矿区,对不同顶板条件矿压与顶板灾害特征并没有形成统一认识,各类顶板条件之间矿压显现的共性和差异研究不足,且尚未形成有效的矿压显现特征评价指标及方法。基于以上问题,首先,将我国煤矿顶板进行分类,划分为浅埋深、坚硬顶板、非坚硬顶板等3种典型条件,其中非坚硬顶板又包括强矿压顶板和弱矿压顶板2种类型。通过大量矿压数据分析,采用基于支架工作阻力P-T曲线、矿压云图、典型工作面来压特征统计及均化循环拟合的综合分析方法,分析各类典型顶板条件工作面矿压显现特征,得出如下结论:①浅埋煤层工作面具有来压强增阻、非来压微增或负增阻、来压频繁且持续时间长、矿压受地表形状影响大等特征。工作面来压期间均化循环曲线表现为对数+指数的复合函数特征,来压期间支架增阻率远高于非来压期间,且工作阻力增速呈现前缓后急的增长趋势。②坚硬顶板工作面具有来压强增阻、来压步距大、有时存在动载冲击等特征。非来压期间增阻率较小,均化循环曲线表现为近似于线性函数的微增阻特征。来压期间,支架增阻率显著提高,均化循环曲线特征与浅埋煤层增阻特征相似。③非坚硬强矿压类型顶板工作面具有来压与非来压界定不明显、持续渐进式顶板灾害等特征。非来压时增阻率高于浅埋及坚硬顶板工作面,来压时则相反;非坚硬弱矿压类型顶板工作面具有来压显现较弱、增阻率较小、局部来压频繁等特征。2种非坚硬顶板工作面均化循环曲线均符合对数函数特征,增阻率呈移架前期快速增长,而后迅速放缓的增长趋势,来压时增阻曲均低于浅埋和坚硬顶板工作面。

     

    Abstract: Roof failures have always accounted for a large proportion of coal mine disasters for a long time, and have always been a problem that plagued coal mine safe production in China.The analysis of strata pressure behavior is very important to the effective prevention and control of roof disasters.At present, most studies only focus on a single mine or individual mining areas, and there is no unified understanding of strata pressure and roof disaster characteristics of different roof conditions.There is insufficient research on the commonalities and differences of pressure manifestation, and the effective evaluation indexes and methods of mining pressure manifestation characteristics have not yet been formed.Based on the above problems, the roofs of coal mines in China are classified into three typical conditions: shallow depth, hard roof, and non-hard roof.Among them, the non-hard roof working face includes two types of strong rock pressure roof and weak rock pressure roof.Through the analysis of a large amount of rock pressure data, the comprehensive analysis method based on the support working resistance P-T curve, the rock pressure cloud chart, the statistics of the typical working face pressure characteristics and the homogenization cycle fitting is used to analyze the characteristics of the working face rock pressure under various typical roof conditions.The following conclusions are drawn:① Shallow coal seam face has the characteristics of increased resistance by incoming pressure, slight increase or negative resistance increase by non-incoming pressure, frequent and long duration of incoming pressure, and large influence of ground pressure on surface shape.The homogenization cycle curve during the pressure on the working face is characterized by a logarithmic + exponential compound function.The resistance increase rate of the support during the pressure is much higher than that during the non-pressure period, and the growth rate of the working resistance shows a slow growth trend afterwards;② Hard roof working face has the characteristics of increased resistance by incoming pressure, large step distance of incoming pressure, sometimes dynamic load impact.The resistance increase rate during the non-compression period is small, and the homogenization cycle curve shows a slight resistance increase characteristic similar to a linear function.During the pressure period, the resistance increase rate of the support is significantly increased, and the characteristics of the homogenization cycle curve are similar to the resistance increase characteristics of the shallow coal seam;③ The non-hard with strong mining pressure type roof face has the characteristics of inconspicuous definition of incoming pressure and non-incoming pressure, and continuous and progressive roof disasters.The resistance increase rate under non-incoming pressure is higher than that of shallow buried and hard roof working faces, while the opposite is the case when under pressure; the non-hard with weak mineral pressure type roof working face has the features of weaker pressure appearance, lower resistance increase rate, and frequent local pressure, etc.The homogenization cycle curves of the two non-hard roof working faces are in line with the characteristics of logarithmic function, and the resistance increase rate shows a rapid increase in the early stage of the frame shift, and then a rapid growth trend.When pressure is applied, the resistance increase curve is lower than that of the shallow buried and hard roof working face.

     

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