切割拉槽中深孔孔内分段爆破数值模拟

Numerical simulation of in-hole segmental blasting in medium-deep hole in cutting groove

针对大冶铁矿切割井上部难以施工至设计高度从而影响立槽高度问题,考虑在切割巷的拉槽中深孔采用孔内分段爆破方案,以使得切割立槽高度达到设计高度,并解决悬顶的安全问题。为分析切割拉槽中深孔孔内分段爆破效果,基于ANSYS/LS-DYNA有限元数值模拟软件,对孔内分段装药和不分段装药两种不同装药结构下中深孔爆破切割立槽处应力变化、损伤区域进行模拟计算研究。结果表明:越靠近模型中部,应力波的叠加作用越强,其有效应力更加集中,所产生的损伤破碎面积更大。在矽卡岩区域内,两种不同装药结构的爆破方式在切割立槽处产生的有效应力大小高于矽卡岩的破坏强度,均能在切割立槽处造成较大面积的损伤破碎。在磁铁矿区域内,分段装药爆破后产生的爆破高度更高,在切割立槽处所产生的有效应力更大,产生的破碎面积更广。结合大冶铁矿现场实际爆破试验,孔内分段爆破后可顺利将悬顶安全处理,使得切割立槽达到设计高度,解决了后期施工生产的难题。

To solve the problem that the construction height of the cutting shaft is hard to achieve the design height in Daye Iron Mine,which may the height of vertical cutting groove,an in-hole segmentation blasting scheme is considered for the medium-deep hole in the cutting drift to make the height of the vertical cutting groove reach the design height,and to solve the safety problem of the flap top.In order to analyze the effect of in-hole segmental blasting in medium-deep holes in cutting groove,based on ANSYS/LS-DYNA finite element numerical simulation software,simulation calculations were conducted to study the stress changes and damage areas in the surrounding rock masses the cutting vertical groove by medium-deep hole blasting under two different charging structures:in-hole segmental charging and non-segmental charging.The results show that the closer to the middle part of the model,the stronger the superposition of stress waves,the more concentrated its effective stress,and the larger the damage crushing area produced in the rock mass.In the Skarn area,the effective stress produced from two different charging structures at the vertical cutting groove are higher than the failure strength of skarn,and both of them can cause large area damage in the vertical cutting groove.In the magnetite area,after in-hole segmented charging blasting,the blasting height is higher,the effective stress is higher in the area of vertical cutting groove,and the crushing area is wider.Combined with the actual blasting test at the site of Daye Iron Mine,the flap top of cutting shaft can be safely handled after in-hole segmental blasting,making the vertical cutting groove reach the design height,and solving the problem for later construction and production.