深部煤层钻屑粒度随钻进深度分布规律

为了研究煤层钻屑粒度随钻进深度分布规律，选取具有冲击危险性的平煤八矿己15煤作为研究对象，采取钻屑量测试和孔口瓦斯浓度监测，通过筛分实验煤样并应用Rosin Rammler分布模型，探究了钻屑粒度和钻屑量大小随孔深变化关系，分析不同点钻屑粒度分布特征。结果表明:小于0.075 mm钻屑粒度分布随孔深变化与钻屑量变化规律相吻合；不同钻孔随深度变化分别对应不同Rosin Rammler分布函数，随着应力过渡越平缓，粒径分布宽度系数n值越小，煤体应力越大粒径相关系数D越大；不同范围钻屑粒度占比大小也会影响钻屑量大小；在钻屑量较大时，孔口瓦斯体积分数会出现增高现象。通过对钻屑粒度分布规律分析，更好地了解深部煤体应力分布，有助于冲击危险的预警。

Distribution laws of particle size of drilling cuttings with drilling depth in deep coal seams

In order to study the distribution laws of particle size of drilling cuttings with the drilling depth in the coal seam,the Ji No.15 coal of Pingdingshan No.8 coal mine with the impact risk was selected as the research object,and the measurement of drilling cuttings amount and the monitoring of gas concentration at the orifice were adopted,through screening the testing coal samples and applying the Rosin Rammler distribution model,the relationship between the particle size of drilling cuttings and the size of drilling cuttings amount with the borehole depth was explored,and the distribution characteristics of particle size of drilling cuttings at different points were analyzed.The results showed that the particle size distribution of drilling cuttings being less than 0.075 mm was consistent with the change of borehole depth and drilling cuttings amount.The variation of different boreholes with depth correspond to different Rosin Rammler distribution functions respectively,and the more gentle the stress transition,the smaller the width coefficient n of particle size distribution,while the larger the coal body stress,the larger the correlation coefficient D of particle size.The proportion of particle size of drilling cuttings in different ranges also affected the size of drilling cuttings amount,when the drilling cuttings amount is large, the gas volume fraction of orifice will increase.Through the analysis on the distribution laws of particle size of drilling cuttings,the stress distribution of deep coal body can be better understood,which is helpful for the early warning of impact risk.