分区控制爆破技术在复杂地质条件公路隧道改造中的应用  

Application of Divisional Controlled Blasting Technology in Reconstruction of Highway Tunnel under Complex Geological Conditions

作　　者：王刚 WANG Gang(Anhui Jiangnan Blasting Engineering Co.,Ltd.)

机构地区：[1]安徽江南爆破工程有限公司,安徽省宁国市242300

出　　处：《现代矿业》2022年第9期264-269,共6页Modern Mining

摘　　要：针对围岩松散、岩溶裂隙发育、溶洞内部泥水填充等复杂地质条件下隧道改造加固工程,对原隧道支护进行预先拆除,并对待拓宽区域进行爆破扩挖,通过精心设计爆破掘进过程中的掏槽方式、装药结构,合理布置孔位,采用理论公式计算各项爆破参数并结合现场实际优化调整,分区块进行爆破施工作业,校核爆破振动、冲击波、飞石等有害效应阈值。最终确定:对于紧急停车带稳定围岩处,采用1.5 m及以上孔深开挖施工,全断面一次爆破;对于软岩及断层破碎带,酌情采用减弱松动爆破,或分台阶、分步骤地进行“多循环、短进尺”的爆破施工,循环进尺不大于1.0 m。对于行车、行人横洞围岩条件较好区域,设计炮孔深度为1.5 m,循环进尺为0.95~1.35 m;围岩软弱区域炮孔深度为1.0~1.5 m,循环进尺为0.8~1.2 m,周边孔均采用光面爆破法进行施工。现场爆破效果表明:爆破后岩石块度均匀,爆破进尺达到设计值,围岩稳定,爆破有害效应得到有效控制,为类似隧道爆破扩挖工程提供了参考。In view of the tunnel reconstruction and reinforcement works under complex geological conditions such as loose surrounding rock,karst fissure development and mud filling in the karst cave,the original tunnel support shall be demolished in advance,and the area to be widened shall be expanded by blasting.Through careful design of the cutting mode and charging structure in the process of blasting exca⁃vation,reasonable arrangement of hole positions,calculation of various blasting parameters by theoretical formulas and optimization and adjustment in combination with the actual situation on site,The blasting con⁃struction shall be carried out in blocks,and the threshold of harmful effects such as blasting vibration,shock wave and flying stone shall be checked.Finally,it is determined that for the stable surrounding rock of the emergency parking zone,the hole depth of 1.5 m and above shall be used for excavation and con⁃struction,and the whole section shall be blasted once;For the soft rock and fault fracture zone,it is appro⁃priate to adopt weakening loosening blasting,or carry out the blasting construction of"multi cycle and short footage"step by step,with the cyclic footage not more than 1.0 m.For the area with good surrounding rock conditions for traffic and pedestrian cross tunnels,the designed blast hole depth is 1.5 m,and the cy⁃clic footage is 0.95~1.35 m;The depth of blast holes in the surrounding rock soft area is 1.0~1.5 m,the cyclic footage is 0.8~1.2 m,and the surrounding holes are constructed by smooth blasting.The field blast⁃ing results show that the rock fragmentation after blasting is uniform,the blasting footage reaches the de⁃sign value,the surrounding rock is stable,and the harmful effects of blasting are effectively controlled,which provides a reference for similar tunnel blasting expansion projects.

关 键 词：复杂地质 隧道改造 控制爆破 爆破振动 

分 类 号：U457.6[建筑科学—桥梁与隧道工程]