巷道爆破掏槽空腔尺寸对爆破效果影响的模拟研究

Simulation on Influence of Cutting Cavity Size of Tunnel Blasting on Blasting Effect

为了研究巷道爆破掘进过程中掏槽空腔直径对崩落孔爆破效果的影响,运用ANSYS/LS-DYNA对掏槽空腔附近崩落孔的爆破效果进行模拟计算。建立崩落孔孔距A为450 mm、崩落孔抵抗线L和掏槽空腔直径B均为400 mm的初始模型,并以该模型为基础,保持L和A不变,逐步增大B建立额外4个模型。计算并绘制崩落区岩石的塑性应变图,分析得出:随着掏槽空腔直径的增大,岩石塑性应变区域开始增大,爆破效果逐渐改善,当B/L=2时炮孔之间的塑性应变区域连通,掏槽空腔直径对爆破的改善效果达到最优水平;提取掏槽空腔外一系列监测点的拉、压应力值进行分析后得到相同的结论。研究结果可为巷道爆破孔网参数设计提供理论依据和技术参考。

In order to study the influence of the cutting diameter size on the blasting effect in the process of blas- ting excavation of roadway, the LS-DYNA was used to simulate the caving holes blasting effect near the cutting cavi- ty. The initial model was established with holes distance 450 mm, burden distance 400 mm and cutting cavity diame- ter 400 mm. On the basis of the initial model, keeping the holes distance and burden distance constant, the additional four models was built by increasing cavity diameter. Calculating and drawing the map of plastic strain within the ca- ving area, the plastic strain area started to expand with the diameter increasing and blasting effect got improved. When the ratio between cavity diameter and burden was 2, the plastic strain areas was connected between the blast holes, and the optimized blasting effect was obtained from the influence of cutting cavity diameter; the same conclu- sions were also obtained from the tensile stress and compressive stress of the monitoring points.