摘要
渝怀铁路新张坝隧道为喀斯特地质条件下邻近既有线单线铁路隧道。为降低新建隧道爆破开挖对邻近既有隧道的振动影响,针对Ⅲ级及以上围岩,提出一种新形式台阶开挖工法——“倒”台阶开挖工法,即先下台阶爆破,再上台阶起爆。上台阶爆破时可充分利用下台阶爆破的临空面,减少单孔装药量,较好控制了施工过程中爆破振动速度,减少隧道施工对既有线运营的影响。上台阶炮孔不受下台阶爆破和出渣影响,施工时可以实现1次钻孔、2次起爆的效果,避免了多次钻孔和从上断面翻渣,减少了工序循环时间,从而加快了施工进度。
The new Zhangba Tunnel on the railway from Chongqing to Huaihua is adjacent to the existing line tunnel under karst geological conditions.In order to reduce the vibration influence of new tunnel blasting on adjacent existing tunnel,in view of the surrounding rock of grade Ⅲ and above,a new form of step excavation method,namely,the backward step blasting method,is put forward,that is,the lower bench blasting is first followed by the upper bench blasting.When the upper step blasting can make full use of the face after the lower step blasting,reduce the charge quantity,better control the blasting vibration speed in the construction process,and reduce the influence of tunnel construction on the operation of the existing line.The blast hole of the upper step is not affected by the blasting and slag of the lower step,and the effect of one time drilling and two times initiation can be realized during the construction.It avoids multiple drilling and slag turning from the upper section,reduces the process cycle time,and thus improves the construction progress.
作者
王连华
WANG Lianhua(China Railway 23rd Bureau Group Co.Ltd.,Chengdu Sichuan 610072,China)
出处
《铁道建筑技术》
2022年第6期161-164,共4页
Railway Construction Technology
基金
中铁二十三局集团有限公司科技研究开发计划项目(2016-12)。
关键词
倒台阶法
近接隧道
爆破施工
振速控制
backward step method
adjacent tunnel
blast construction
vibration control
作者简介
王连华(1977-),男,山东临朐人,高级工程师,主要从事施工管理方面的工作,E-mail:731794091@qq.com。
