离心不耦合条件下寒区碎软岩体预裂爆破参数优化方法

Optimization Method for Pre-splitting Blasting Parameters of Fractured Soft Rock Mass in Cold Regions under Centrifugal Decoupling Conditions

一般来说,预裂爆破采用同心不耦合装药结构,但由于药柱自身重力原因,药柱和炮孔壁贴合在一起,这种情况可能增强了对预裂爆破保留岩体的损伤。基于传统预裂爆破技术,结合理论分析,提出了离心不耦合装药条件下任意一点的不耦合系数计算公式,推导出其与同心不耦合系数的关系,并比较了2种装药条件下预裂爆破对保留岩体的损伤情况。以白云鄂博西矿为例,在现有2种规格预裂药柱基础上,依据理论分析得出:在不改变预裂孔直径的前提下,当预裂药柱直径为60 mm时,需要对预裂孔孔距和预裂孔装药结构进行优化。通过开展现场试验,对预裂孔孔距和预裂孔装药结构进行了优化,得出了最佳孔网参数。通过三维倾斜摄影技术建立三维模型,对孔网参数优化前后的爆破效果进行了评价,孔网参数优化后半壁孔率提升了27.09%。研究表明:孔网参数优化后,对于保护采场边坡、维护边坡安全稳定具有积极作用,对于类似工程也有借鉴意义。

In general,pre-splitting blasting generally adopts a concentric uncoupled charge structure,but due to the gravity of the charge column,the charge column is attached to the hole wall,which may enhance the damage to the reserved rock mass of presplitting blasting.Based on the traditional presplitting blasting technology and theoretical analysis,the calculation formula of the uncoupling coefficient at any point under the condition of centrifugal uncoupling charging is put forward,and the relationship between the formula and the concentric uncoupling coefficient is deduced.Taking Baiyuneboxi Mine as an example,based on the existing two specifications of pre-cracking charge column,the theoretical analysis shows that,under the premise of not changing the diameter of pre-cracking charge column,when the diameter of pre-cracking charge column is 60 mm,it is necessary to optimize the hole distance and charge structure of pre-cracking charge.Through the field test,the hole distance and the charge structure of the pre-crack hole were optimized,and the optimum hole mesh parameters were obtained.The blasting effect before and after the optimization of hole mesh parameters was evaluated by three-dimensional oblique photography technology.After the optimization of hole mesh parameters,the porosity of half wall was increased by 27.09%.The results show that the optimization of pore mesh parameters has a positive effect on protecting the stope slope and maintaining the safety and stability of the slope,and also has reference significance for similar projects.