高纬高寒地区冻土爆破效果优化研究

Optimization Study on Blasting Effect of Frozen Soil in High Latitude and Alpine Region

针对高寒高纬度地区不同冻土厚度下爆破块度大块率高的难题,在乌努格吐山铜钼矿冬季低温下进行爆破漏斗试验。根据试验结果利用利文斯顿爆破漏斗理论确定了冻土装药参数与爆破漏斗参数之间的关系,计算出冻土层的变形能系数,分析了不同冻土层厚度的爆破漏斗特性曲线。在装药量为4 kg时,冻土临界深度为1.3 m,最佳埋置深度为0.84 m,变形能系数为1.06;在装药量为8 kg时,冻土临界深度为1.7 m,最佳埋置深度为1.2 m,变形能系数为1.05;在装药量为12 kg时,冻土临界深度为2.2 m,最佳埋置深度为1.34 m,变形能系数为0.95。根据爆破立方根定律,推导出适用于现场冻土区的最佳装药参数,经过对不同冻土层厚度多种爆破参数下爆破效果对比分析,采取“分区域,分阶段”原则优化爆破效果,对于弱冻层区域采用减小堵塞长度并增加装药高度的方法提高爆破质量;对于强冻土区主爆孔周围增加辅助孔来降低冻土层大块率。总结出适用于高寒地区随冻土层厚度变化的爆破参数优化方案,爆破效果改善明显,在很大程度上降低了冻土层爆破后的大块率产出,提高供矿率。

Aiming at the problem of high boulder yield under different thicknesses of frozen soil in high latitude and alpine region,blasting crater tests were carried out at low temperatures in winter in Unugtushan copper-molybdenum mine.According to the test results,the relationship between the charge parameters and the blasting crater parameters is determined by using the Livingston blasting crater theory.Simultaneously,the deformation energy coefficient of the frozen soil layer is calculated,and the blasting crater characteristic curves of different frozen soil thicknesses are analyzed.When the charging amount is 4 kg,the critical depth of the frozen soil is 1.3 m,the optimal depth is 0.84 m,and the deformation energy coefficient is 1.06.When the charging amount is 8kg,the critical depth of the frozen soil is 1.7 m,the optimal depth is 1.2 m,and the deformation energy coefficient is 1.05.When the charging amount is 12kg,the above parameters are 2.2 m,1.34 m and 0.95,respectively.According to the similarity law,the optimal charging parameters which are suitable for the frozen soil area on the site are derived,the blasting effect under multiple blasting parameters of different frozen soil thicknesses is compared and analyzed.In addition,the blasting effect is optimized by the principle of“sub-regions and stages”.For weak frozen soil,the blasting effect can be improved with shorter stemming length and longer charge length.For strong frozen soil area,auxiliary holes are added around the main blasting holes to reduce the boulder yield.Furthermore,the optimization scheme of blasting parameters which is suitable for the change of frozen soil layer thickness in Alpine region is summarized.As a result,the blasting effect is significantly improved,which greatly reduces the boulder yield after blasting of the frozen soil layer and improves the ore supply rate.