布孔方式及延期时间对煤体破碎效果影响的数值模拟

Numerical simulation on the influence of boreholes arrangement and delay time on coal crushing effects

针对煤体爆破中不同装药布孔方式及延期时间对煤体破碎效果的影响,本文采用ANSYS-LS/DYNA进行了数值模拟,并对计算结果进行分析。结果表明:爆炸应力波在煤体中产生叠加效应,煤体的破碎主要以拉伸为主;随着孔距排距比的增加,煤体的破碎程度呈现先增加后降低的趋势;当孔距与排距比为1.5时,三角形布孔中心所受应力峰值和煤体的破碎程度均达到最大,分别为175 MPa和9.6%;空孔周围裂纹呈环状分布,且当孔距与排距比为1.0或1.5时,裂纹主要集中在三角形内部;孔间延期时间为0.5 ms时较1.0 ms时的裂纹分散度大,且随着排间延期时间的增加裂纹数有所增加。

According to the effect of different charging and boreholes arrangements and delay time on coal crushing effect in coal blasting,this paper used ANSYS-LS/DYNA to carry out numerical simulation and analyzed the calculation results.The results show that the explosion stress wave has an supper position effect in the coal,and the coal is mainly broken by tensile.With the increase of ratios of borehole distance and row distance,the crushing of the coal increased first and then decreased.When the ratio of borehole distance and row distance is 1.5,the peak stress in the center of the triangular of boreholes and the degree of coal fragmentation reached the maximum,which are about 175 MPa and 9.6%,respectively.The cracks around the empty hole were annularly distributed.When a/b were 1.0 or 1.5,the cracks were mainly concentrated inside the triangle.When the delay time between boreholes is 0.5 ms,the cracks dispersion is larger than that of 1.0 ms.The number of cracks increases with the increase of delay time between rows.