摘要
合理的开挖程序和轮廓爆破方式是深埋地下厂房施工中的关键技术之一。首先总结并综合分析我国已建和在建的主要大型水电工程地下厂房的岩体开挖程序与轮廓爆破方式。在考虑岩体初始应力场和邻近炮孔的联合影响基础上,基于爆炸气体驱动的轮廓爆破裂缝扩展过程分析,论证了高地应力区强约束条件下预裂爆破形成裂缝的可能性。研究表明,地应力是影响预裂爆破形成裂缝的主要因素,当垂直于厂房轴线的水平向岩体应力超过10～12 MPa时,一般不应采用先预裂、再扩挖的开挖程序,而宜选用先拉槽、再预裂或光面爆破的开挖程序。
A reasonable excavation procedure and contour blasting method is one of the key techniques for construction of deep underground powerhouse.Firstly,the excavation procedures and contour blasting methods adopted for the underground powerhouses of large-scale hydropower stations under building or completed are summarized and analyzed.Secondly,based on the analysis of the propagation of cracks driven by explosion gases during contour blasting,and taking into account the combined effects of initial in-situ stress of surrounding rock mass and the adjacent blast holes,the possibility of stable propagation of pre-split cracks under confinement of high lateral in situ stress is demonstrated.The results show that the in-situ stress of surrounding rock mass is a main factor to control the crack propagation for contour blasting.And when the lateral in-situ stress vertical to the axis of underground powerhouse is larger than 10–12 MPa,it is not feasible to employ a excavation procedure of pre-split first followed by the main rock excavation.Alternatively,an excavation procedure of middle cut blasting carried out first,followed by pre-split or smoothing blasting is recommended.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2011年第8期1531-1539,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点基础研究发展计划(973)项目(2010CB732003)
"十一五"国家科技支撑计划项目(2008BAB29B01)
国家自然科学基金资助项目(50909077)
关键词
岩石力学
地下厂房
开挖程序
预裂爆破
光面爆破
地应力
rock mechanics
underground powerhouse
excavation procedure
contour blasting
crack propagation
in-situ stress
