液态CO_2相变破岩桩井开挖技术  

Liquid CO_2 phase-transforming rock fracturing technology in pile-well excavation

作　　者：谢晓锋[1] 李夕兵[1] 李启月[1] 马海鹏 刘小雄 XIE Xiaofeng;LI Xibing;LI Qiyue;MA Haipeng;LIU Xiaoxiong(School of Resources and Safety Engineering,Central South University,Changsha 410083,China;Hunan Junkai Static Blasting Technology Co.Ltd.,Changsha 410008,China)

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083 [2]湖南军凯静爆科技有限公司,湖南长沙410008

出　　处：《中南大学学报（自然科学版）》2018年第8期2031-2038,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41630642);国家重点研发计划项目(2016YFC0600706)~~

摘　　要：为研究液态CO_2相变破岩技术在硬岩桩井开挖中的可应用性,分析CO_2破岩原理,得出泄爆压力与释放能量、TNT当量的关系,进行CO_2破岩成井现场试验和振动监测。研究结果表明:适量的空孔可创造临空面,明显降低质点振动速度,增强破岩效果,但空孔过多会增加泄爆能量的耗散通道,弱化破岩效果或导致破岩失败;CO_2破岩振动波的持续时间短、衰减快、高频成分少,各分速度的主频带一般在100 Hz以下,主振频率集中在20 Hz左右;在半无限岩体中,CO_2破岩区域可分为压碎区和破裂区,压碎区直径为管径的3~4倍,破裂区直径为管径的10~15倍;CO_2破岩技术克服了传统炸药爆破的缺点,是一种高效的台阶破岩方法,还可有效应用于硬岩桩井开挖中,为类似工程岩体开挖提供了新思路。To study the applicability of rock fracturing technology of liquid CO2 phase-transforming in pile-well excavation,the principle of CO2 rock-breaking was analyzed,the relationship between impact pressure and energy as well as TNT equivalent was obtained,and a field experiment and vibration monitoring of CO2 rock fracturing excavation was conducted.The results show that appropriate empty holes can create free face and obviously decrease the particle vibration velocity,which enhances the rock fracturing quality.However,too many empty holes will increase the dissipative channel of explosion venting energy and weaken the rock breaking effect,or cause the failure of rock fragmentation.In addition,the vibration wave of CO2 rock fragmentation has a short duration,fast attenuation and little high frequency components.The main frequency band of each velocity component is usually within 100 Hz and concentrates about 20 Hz.Furthermore,in semi-infinite rock mass,the CO2 rock fracturing zone can be divided into cracked zone and fracture zone,the cracked zone diameter is 3-4 times of the tube diameter,and the fracture zone diameter is 10-15 times of the tube diameter.In conclusion,the liquid CO2 phase-transforming rock fracturing technology can overcome the shortcomings of traditional explosive blast,and it can not only break rock effectively with bench method,but also be valid in hard rock pile-well excavation,which provides a new thought for similar engineering rock mass excavation.

关 键 词：液态CO2 相变破岩 桩井开挖 爆破振动 

分 类 号：TU473[建筑科学—结构工程]