辽北地区地下洞室爆破参数研究与应用

Research and Application of Underground Cavities Blasting Parameters in Northern Liaoning

文章对辽宁北部地区大型跨流域地下引水隧洞钻爆法施工的优缺点进行了分析研究,从工程实践角度提出由于钻爆法施工本身的特殊性造成的超欠挖问题,以及由于超挖所带来的初期支护喷射混凝土厚度增加,导致的原材料浪费严重,施工成本增加、工期延长、回弹率增大、2期衬砌混凝土厚度增加导致的浇筑时不容易振捣与质量不易受控,水泥水化热增大,温控难度增加,混凝土容易出现裂缝、以及顶拱回填灌浆不易密实容易留有空隙、后期运行易出现水力劈裂等诸多问题,通过凝灰质砂岩1751m洞段爆破参数的优化设计研究,将径向平均超挖22.5cm降低至14.3cm,为同类地质条件施工提供参考。

The advantages and disadvantages of large-scale cross-basin diversion tunnels in northern Liaoning with the borehole blasting construction method are analyzed in this paper,from the perspective of engineering practice,the problem about over-under-excavation caused by the speciality of drilling and blasting construction itself and the over-excavation are put forward,including the initial support of increased thickness of shotcrete,which results in serious waste in raw materials,causing the increase of construction costs,extension of the construction period,increase of rebound rate,increase of the lining concrete thickness in second-stage,vibration is not easy to vibrate and the quality is not easy to control. Cement hydration heat increases,the temperature control difficulty increases,the concrete is prone to cracks,and the top arch backfill grouting is not easy to be dense and easy to leave voids,and the hydraulic runoff is prone to occur in later operation. Through optimization of the blasting parameters of the 1751 m section of the tuffaceous sandstone,the radial average over-excavation of 22. 5 cm was reduced to 14. 3 cm,which provides reference for the construction under similar geological conditions.