高原露天台阶上部冻层破断规律数值分析  

Numerical analysis of the upper frozen layer fracture in plateau open-pit bench

作　　者：李尧臻 韩雨东 常远 LI Yaozhen;HAN Yudong;CHANG Yuan(School of Civil Engineering,University of Science and Technology Liaoning,Anshan Liaoning 114051,China)

机构地区：[1]辽宁科技大学土木工程学院,辽宁鞍山114051

出　　处：《有色金属（矿山部分）》2024年第3期23-31,共9页NONFERROUS METALS(Mining Section)

基　　金：国家自然科学基金资助项目(52074292);辽宁科技大学大学生创新创业训练项目。

摘　　要：上部冻层是影响高原露天台阶爆破效果的主要因素之一,为明确高原露天台阶上部冻层在爆破荷载作用下的破断规律,利用颗粒流数值方法模拟了天然单冻层和人工复合双冻层分别在单、双排炮孔作用下的破断过程,分析了冻层破断过程的速度、冲击压力和破断后的块度特征。结果表明:冻层在爆破荷载作用下经历了产生裂隙-局部隆起-宏观断裂的破坏过程,对于人工复合冻层,由于上部增加了碎石土层,冻层厚度增大,削弱了冻层整体的隆起趋势,导致破碎块度增大。双排炮孔之间冻层受到的冲击压力率先达到峰值,但靠近自由面的冻层受到的冲击压力峰值更高。单、双冻层在爆破荷载作用下的破断问题可简化为冲击压力作用下的结构断裂问题。双冻层台阶爆破大块率比单冻层大块率高4%~6%,建议在高原露天矿山爆破中,优先通过冻土层厚度确定需要进行特殊处理的区域,并通过调整延期时间达到降低大块率,提高铲转挖运效率的目的。The upper frozen layer is one of the main factors affecting the blasting effect of the plateau open-pit bench.To clarify the fracture law of the upper frozen layer of the open-pit bench under the blasting load in the cold area of the plateau,this paper uses the particle flow code method to simulate the fracture process of the natural single frozen layer and the artificial composite double-frozen layer under the action of single and double rows of blast holes respectively.The frozen layer′s speed,impact pressure,and fragmentation characteristics were analyzed.The results show that the frozen layer undergoes the failure process of cracking-local uplift-macro fracture.For the artificial composite frozen layer,the thickness increases due to the increase of the gravel soil in the upper part,which weakens the overall uplift trend of the frozen layer and leads to increased fragmentation.The impact pressure on the frozen layer in the middle of the double-row blast hole first reaches the peak,but the peak value on the frozen layer near the free surface is higher.The fracture problem of single and double frozen layers under blasting load can be simplified as the structural fracture mechanics problem under impact pressure.The large block rate of double-frozen-layer bench is 4%to 6%higher than that of single-frozen-layer.It is suggested that in the blasting of plateau open-pit mines,the area that needs special treatment should be preliminarily determined by the thickness of the frozen layer,and the large block rate should be reduced by adjusting the delay time to improve the efficiency of shovel-to-digging.

关 键 词：高原寒区 冻层 爆破荷载 颗粒流 块度特征 

分 类 号：TD854[矿业工程—金属矿开采]