铁路隧道下穿既有高速公路隧道施工控制技术研究

研究目的:解决新建隧道近距离穿越既有隧道时,既保证新建隧道施工安全,又能使既有线正常运营的问题。研究方法:针对温福铁路头岭隧道下穿既有高速公路隧道工程的实际情况,结合国内外研究成果和国家现有规程,在分析既有隧道健全度及施工对策的基础上,对交叉点附近新建隧道的施工方案及既有高速公路隧道的监控量测措施进行了分析研究。研究结果:得出了几种施工技术和相应的参数、控制标准。研究结论:(1)近距离爆破振动施工可能会产生严重危害,必须引起高度重视,因此,头岭隧道穿越段施工之前,应对既有隧道衬砌强度、衬砌背后空洞分布、衬砌抗震性等进行必要的评估,制定爆破振动控制基准,进行合理的爆破参数研究。(2)在新建隧道掌子面推进到离交叉点3~4倍洞径时,应开始做好既有隧道内的监控量测,通过监测分析结果,合理调整开挖方法、爆破参数及起爆方式,确保既有隧道安全。(3)交叉段施工完成之后,对既有隧道交叉点附近隧道衬砌结构应重新进行安全性评价,确保既有隧道不会因时间推移而产生破坏。

Research on Construction Control Technology for Railway Tunnel Underneath Passing Existing Expressway Tunnel

Research purposes: The purposes are to ensure the construction safety of newly-built tunnel and make(existing) road open to traffic usually while the newly-built tunnel underneath passes existing(tunnel) nearby.Research methods: According to the real construction situation of Guantouling Tunnel underneath passing existing(expressway) tunnel on Wenzhou-Fuzhou Railway Line and in combination with the research achievements at home and(abroad),and current state codes,the analysis and research have be made on construction scheme for newly building a tunnel around cross point and on measures for monitoring and measuring the existing expressway tunnel based on the (analysis) of integrity level of existing tunnel and construction countermeasures.Research results: Several construction techniques and their relative parameters and control standard are presented.Research conclusions:(1) More attention should be paid to the serious harm probably caused by blast vibration(nearby).Therefore,it is necessary to evaluate the lining strength of existing tunnel,cavity distribution behind lining and(earthquake) resistant behaviour of lining,to work out the basic control standard for blast vibration and make research on rational blast parameters before construction of intersection of Guantouling Tunnel.(2) When the working face of newly-built tunnel approaches to hole diameter of 3-4 times from cross point,the monitoring and measurement in the(existing) tunnel should be done well.With the analysis result of monitoring,the adjustments should be made rationally of(excavation) way,blast parameters and method of ignition in order to ensure the safety of the tunnel.(3) After finishing the construction of intersection,the safety should be re-evaluated to tunnel lining structure(near) the cross point of(existing) tunnel in order that the tunnel will not be damaged with time passing by.