为提高露天开采过程中高温钻孔爆破的安全性，加快高温区域剥离速度，采用现场试验的方法，研究了液态CO2对高温爆破钻孔的降温规律，证实了采用液态CO2对高温爆破钻孔降温的可行性。试验同时向8个钻孔灌注液态CO2，灌注时间为8 min，钻孔平均灌注量为0．32 m3。试验钻孔深12 m，孔径为140 mm，初始温度在50～120℃之间。试验结果表明：液态CO2对单个钻孔有明显的快速降温效果，降温后钻孔温度从0℃回升至50℃用时15 min以上，满足安全爆破的时间要求；多孔同时进行降温时，受钻孔初始温度及孔内形成干冰的影响，各钻孔温度从0℃回升至50℃的安全爆破时间段不重合，难以满足同时装药、起爆的要求。应针对钻孔的不同情况，进一步改进液态CO2钻孔降温工艺。%In order to improve the safety of high-temperature drill blasting in the process of opencast mining , and increase the stripping speed of high-temperature zone , the cooling rules of liquid carbon dioxide on high-temperature blasting borehole were studied by using the method of field test , and the feasibility of using liquid carbon dioxide for borehole cooling of high -temperature blasting was verified .In the tests, liquid carbon dioxide were poured into eight boreholes simultaneously , the pouring time was 8 minutes, and the average pouring amount of borehole was 0.32 m3 .The borehole depth was 12 m, the borehole diameter was 140 mm, and the initial temperatures were between 50℃and 120℃.The test results showed that liq-uid carbon dioxide had an obvious rapid cooling effect on single borehole , and the time that the borehole temperature rose a-gain from 0℃to 50℃after cooling was above 15 minutes, which could meet the time requirement of safe blasting .When conducting cooling on multiple boreholes at the same time , the time periods of safe blasting that the borehole temperature rose again from 0℃to 50℃for each borehole were not coincident due to the influence by initial temperature of borehole and the formation of dry ice in the borehole , which was difficult to meet the requirements of charging and blasting si -multaneously . The borehole cooling technology by liquid carbon dioxide should be further improved according to different conditions of bore -hole .
展开▼
