巷道爆破掘进中侧压系数对薄层复合顶板影响的数值分析

NUMERICAL ANALYSIS ON THE INFLUENCE OF HORIZONTAL PRESSURE COEFFICIENT ON THIN-LAYER COMPLEX ROOF DURING THE BLASTING DRIVING ROADWAY

为分析侧压系数在巷道爆破掘进时对薄层复合顶板的影响,针对东荣二矿17#煤顶底板地质条件建立相应数值计算模型,采用非线性有限元动力分析软件ANSYS/LS-DYNA分析了巷道爆破掘进中在不同侧压系数条件下对薄层复合顶板的影响。分析结果表明:不同侧压系数对薄层复合顶板不同区域影响效果不同,爆炸对顶板的冲击压力影响较大,而对顶板的振速影响较小。随着侧压系数的增大,在掘进工作面后方,爆炸初期顶板压力减小,而中、后期压力逐渐增大;在掘进工作面的前方,爆炸初期、后期顶板压力逐渐增大,而中期压力逐渐减小。因此,巷道爆破掘进时,在工作面后方应及时支护,提高顶板的强度,以减小爆破对后方顶板离层的加速作用;同时应优化爆破参数,以降低爆破对前方顶板的损伤作用,以防掘进过程中发生冒顶事故。

In order to analyze the effect of horizontal pressure coefficients on thin-layer complex roof during the blasting driving roadway, corresponding simulation model was established according to geological condition of 17^# coal seam located in Dongrong 2nd mine and the effect of blasting driving roadway on thin-layer complex roof was analyzed in the condition of different horizontal pressure coefficients by using nonlinear finite element dynamic analysis software ANSYS/LS-DYNA. The results showed that the effect was different in different regions of thin-layer complex roof in the condition of different horizontal pressure coefficients, the effect of explosive on shock pressure of the roof was large, but its effect on vibration ve- locity of the roof was small. With the horizontal pressure coefficient increasing, the pressure of the roof be- hind the driving face was decreased at the pre-explosion, and it was increased at the mid-explosion and post-explosion; the pressure of the roof in front of the driving face was increased at the post-explosion and pre-explosion, and it was decreased gradually at mid-explosion. Therefore, the roof behind the driving face should be supported timely to improve its strength and to decrease its separation while blasting driving roadway; the blasting parameters should be optimized to reduce the blast damage to the roof in front of the driving face for preventing roof caving during blasting.