基于压力拱理论的螺旋钻机开采单层钻孔参数优化

Optimization of single-layer drilling parameters based on pressure arch theory in auger drilling

为科学设计某矿螺旋钻机钻孔布置参数,根据钻孔周围应力分布特点,提出相邻钻孔间煤柱有效宽度的确定方法,确定单层钻孔排布关键参数;结合压力拱理论,提出以永久隔离煤柱中点处应力集中系数为永久隔离煤柱宽度合理性的判定标准;利用正交试验法设计9组正交试验方案,运用有限元差分软件进行数值模拟,基于压力拱理论分析模拟结果,选取最优方案。结果表明:较小的相邻钻孔间煤柱宽度使钻孔上原本各自独立的压力拱形成1个压力拱,关键层能有效地限制压力拱外边界高度,永久隔离煤柱能有效消除相邻钻孔群间影响;所提出的相邻钻孔间煤柱有效宽度确定方法适合螺旋钻机开采参数设计;方案9,即相邻钻孔数量25个,相邻钻孔间煤柱宽度1 m,永久隔离煤柱宽度10 m,关键层下围岩较稳定,监测煤柱内塑性区宽度与有效宽度比值0.4,永久隔离煤柱中点处应力集中系数1.382,相比之下,该方案属最优。

In order to scientifically design the drilling layout parameters of auger drilling rigs in a certain mine,according to the stress dis⁃tribution characteristics around the drilling holes,a method for determining the effective width of coal pillar between adjacent drilling holes was put forward,and the key parameters of single-layer drilling arrangement were determined.Combined with the theory of pressure arch,it is proposed that the stress concentration coefficient at the middle point of the permanently isolated coal pillar is used as the criterion to determine the rationality of the width of the permanently isolated coal pillar.The orthogonal test method was used to design nine orthogonal test schemes,and the finite element difference software was used for numerical simulation,based on the pressure arch theory to analyze the simulation results and optimize the optimal scheme.The results show that the smaller width of coal pillar between adjacent boreholes makes the originally independent pressure arch on the borehole form a pressure arch,and the key layer can effectively limit the height of the outer boundary of the pressure arch,and the permanent isolation of the coal pillar can effectively eliminate the influence of adjacent borehole groups.The proposed method for determining the effective width of coal pillars between adjacent drilling holes proposed in this paper is suitable for the design and study of mining parameters of auger drilling rig.In Scheme 9,the number of adjacent boreholes is 25,the width of coal pillars between adjacent boreholes is 1 m,and the width of permanent isolated pillar is 10 m,and the surrounding rock under the key layer is relatively stable.The ratio of the width of plastic zone in the monitoring coal pillar to the effective width is 0.4,and the stress concentration coefficient at the middle point of permanent isolation pillar is 1.382.This scheme is the best.